Final Report Summary - SURFUNCELL (Surface functionalisation of cellulose matrices using cellulose embedded nano-particles)
Executive Summary:
1.1 Executive summary
Polysaccharides produced by plants and microorganism are the most abundant biopolymers on earth. They are used by manly as low complex and low value products and their exceptional properties are mostly neglected. These biopolymers are multifunctional and stereoregular by nature, show a large variety of complex structures based on small chemical variations. This projects vision was to contribute knowledge how these specific properties can be utilized more effectively in order to transfer these biopolymers into high value products.
The projects main RTD objective was to create new, smart and bio-based surface nanostructured polymer composites providing high value surface functionalities (mechanical, chemical, selective interaction properties). These new materials should be composed of nano-scaled polysaccharide layers with embedded nano-particles, for the coating of different cellulose matrices. The compounding is restricted to the biopolymers surface and outer layers, providing the 'filler' to the domain where it is required and avoiding the deterioration of the matrix materials mechanical properties.
A multidisciplinary team provided the needed complimentary know how. The integrative work program defined strategic routes towards new materials followed by up-scaling of some results into industrial pilot production. Experimental investigations of the basic principles together with extended modelling have provided the necessary understanding to develop the technologically best candidates towards production. LCA has provided decision making support to choose process routs environmentally acceptable for manufacturer and the society.
Finally 4 from the industrial partner envisaged products and two scientific hot topic were developed towards pilot production stages.
The basic research provided new cellulose derivatives with specific functionalities, new synthetic routs for the save production of different kinds of nanoparticles and allowed to build up an extended know how to produce biobased nanostructured surface compounds.
These innovative products comprise:
- Water purification membranes providing reduced fouling (elongated operating life time) and degradation of hormone residues present in drinking water via immobilized enzymes.
- Cellulose fibres with integrated and stable immobilized silver nanoparticles providing desired antimicrobial properties. These fibres will be integrated into fabrics used in hygienic, public and sports application.
- Cellulose based packaging material with improved water vapour barrier properties. Cellulose packaging material replacing synthetic polymer packaging materials has low resistance against humidity permeation. Non-renewable materials providing these barrier properties can be substituted by a barrier coating using natural compounds.
- High-yield pulp office paper with same aging resistance and mechanical strength as conventional wood free office paper.
- The scientific hot topics develop to demonstrator stages are both high tech cellulose based coatings; one amino cellulose coating for the immobilization of protein receptors and one cellulose coating for the structuring of micro-scaled channels for microfluidic devices and 3 dimensional structures using digital printing.
Project Context and Objectives:
1.2 Summary description of project context and objectives
1.2.1 Project concept and objectives
Polysaccharides produced by plants and microorganism are the most abundant biopolymers on earth. They are used by humans for many purposes beside nutrition. Partially as they are provided by nature and partially derivatized and processed for different purposes as textile or technical fibers, membranes, packaging material and ingredients in food, cosmetics, toilet articles and pharmaceuticals. These biopolymers are multifunctional and stereoregular by nature, show a large variety of complex structures based on small variations of their chemical primary structure. Beside all development made during decades we still make in general no use of their specific and often extraordinary properties. The projects vision was to contribute knowledge how these specific properties can be utilized more effectively in order to transfer these biopolymers into high value products.
The projects main RTD objective was to create new, smart and bio-based surface nanostructured polymer composites providing high value surface functionalities (mechanical, chemical, selective interaction properties). These new materials should be composed of nano-scaled polysaccharide layers with embedded nano-particles, for the coating of different cellulose matrices. The compounding is restricted to the biopolymers surface and outer layers, providing the 'filler' to the domain where it is required and avoiding the deterioration of the matrix materials mechanical properties.
This has several major advantages: the filler is not compounded into the bulk material, the technical process of cellulose matrix production (films, membranes, fibers) can stay unchanged, the deterioration of the matrix materials mechanical properties is avoided and only small quantities of nano-particles are needed to gain the expected / desired effects.
The project is based on new knowledge about the feasibility of coating a solid cellulose surface with soluble polysaccharides (PS) in an irreversible manner due to their chemical similarity offering the interaction by H-bridges and hydrophobic interactions. This is even the case with oppositely charged and derivatized PS as long as they do not have a significant amount of side chains. A further feasibility step proved that the incorporation of nano-particles into this layer is possible if certain conditions are obeyed. The projects target is the development of this strategic route into new materials and the up-scaling of some results into an industrial pilot production state. This comprised the study of these new effects (cellulose/polysaccharides dissolution, structuring with nano-particles and irreversible coating of cellulose matrices) with the aims of understanding and mastering them, the exploration of their properties and applicability and development of the most promising ones of the new materials a pilot scale production process. This concept opens several routes, each with many different applications, to prepare a completely new class of materials:
Nanostructured biopolymer surface composites made of
polysaccharide - coated cellulose with embedded nano-particles
The development of new, innovative biomass-based materials is of strategic importance. Decreasing oil resources, the increase of the global warming and the awareness of European citizens of the need of more eco-friendly products are the major driving forces. The tremendous development of bio-based products, mainly materials and polymers in the Third Counties (Asian, Brazil) and in the USA, is driven by the wide, mainly unexplored or unknown, opportunities of developing new products by chemical manipulation of bio-based materials. If Europe wishes to be competitive and develop its industry, creating wealth and jobs, it has to boost research that can be transformed into new products. This was the aim of our project which is fully in line with EU directives like the Renewable Energy Roadmap, the Biomass Action Plan or the Environmental Technology action Plan.
Accordingly, this project aimed at the development of a new class of sustainable materials with substantially improved technological properties. Several research and technology transfer tasks were defined comprising:
- Derivatize the coating polysaccharides to gain expected functionalities and to dissolve them at the molecular / nano level;
- Prepare and characterize stable dispersions of different kinds of nano-particles;
- Coat the solid cellulose matrix materials with nano-scaled polysaccharide layers;
- Integrate different kinds of nano-particles into this coating;
- Tune the interaction forces to achieve irreversible adsorption or controlled release;
- Generate a deep understanding for the involved physical and chemical processes using different modelling approaches;
- Characterize the properties of the new materials and compared to existing material;
- Scale up the most promising new materials and transfer into a pilot production stage;
- Prove the sustainability of the new materials by life cycle and economic analysis.
The project brought together a multidisciplinary team In order to achieve this, each partner providing different and complimentary know how. It combined the team with the help of an integrated work program starting with fundamental research in order to prove the technological concept, and extend this from laboratory scale via a primary up-scaling into industrial demonstrator systems. Experimental investigations of the basic principles together with extended modelling have provided the necessary understanding to extend it towards production. LCA has provided decision making support to choose process routs environmentally acceptable for manufacturer and the society.
1.2.2 Formation of functionalised biobased polymer compounds using interface processes
Non-soluble polysaccharides, especially oriented moieties like cellulose, exhibit huge surface areas. This creates conditions for strong physical interactions (Lewis acid based interactions and van der Waals forces) with chemically similar compounds. As a consequence, many naturally occurring polysaccharides (PS) adsorb more or less irreversibly on cellulose surfaces. It is also possible to dissolve chemically modified/functionalised PS and to adsorb them from solution irreversibly on a cellulose matrix, providing surface functionalized materials with new mechanical properties. In an additional step a wide variety of nanoparticles can be embedded into this coating layer.
First step is the functionalization of dissolved PS, followed by deposition of a cellulose surface and embedding of nano-particles into this film. In an alternative process rout the nano-particles interact first with the functionalized PS and this assembly is afterwards adsorbed on the cellulose surface. The strong interaction between the adsorbed PS coating and the cellulose matrix is responsible for the irreversible surface treatment.
One key feature of the developed method is, that a wide range of materials can be prepared, opening the way to new functionalized composite materials in an area where so far only a small range of possibilities have been envisaged. Examples of property enhancement are:
- Selective interaction possibilities;
- Improved mechanical, chemical and thermal stability, barrier properties;
- Surfaces providing a controlled release of active substances;
- Surfaces showing tunable properties;
- Catalytic properties based on renewable materials;
- Selective sensor surface;
- Biocompatible medical devices.
The second key feature is that many desired surfaces properties are achievable using sustainable and environmental friendly processing routes turning renewable materials into high-value goods.
The final processing happens exclusively in heterogeneous reaction systems where surface area and interfacial processes play a dominant role. The understanding of physical interactions acting in this heterogeneous systems consisting of functional compounds (soluble polysaccharides, polyelectrolytes, surfactants, pigments and nano-particles) and the macroscopic cellulosic matrix material was improved and the processes finally utilized technologically. The reasons for the processes complexity are the diversity and limited and inherent micro-heterogeneity of natural polysaccharides. Therefor the derivatisation, modification and processing of PS is often difficult and nano-scale structuring is especially complicated. This is to a large extent the reason why more advanced polymer technology is almost exclusively based on petrochemistry.
The transformation of natural polymers, presently used mainly in low-cost, low-added value commodities, into economically and ecologically sustainable high-tech, high added value products is a challenge. Our project provided several ways to achieve this (Figure 1):
- Deposition of chemically modified/ specifically functionalized polysaccharides in (structured) nano-layers on the surface of cellulose matrices (foils, membranes, fibres). The irreversible adsorption of these layers on cellulose is due to their chemical similarity, resulting in the possibility of hydrogen bonding and hydrophobic interactions.
- Incorporation of nano-particles into this surface layer in two ways:
- Dispersion of the nano-particles into polysaccharide solutions and deposition of the formed aggregates onto the cellulose matrix.
- Deposition into the already formed polysaccharide surface layer.
These processing routes are finishing treatments of already shaped renewable polymers rendering them into high-value goods. Preferably aqueous solvents and environmentally friendly processes are employed. Modifications of the matrix materials production conditions are not be necessary. This strategy opened several ways to create new classes of bio materials with tailored functions and properties applicable in the following fields:
- Separation technology: Materials with selective interaction properties (with organic, inorganic and biological compounds), tunable by environmental conditions.
- Technical fibres and foils: Specific surface modification (strength, abrasion resistance, thermal and chemical stability, hydrophilicity/hydrophobicity '¦).
- Improved material properties: Flame resistance, conductivity, antimicrobial activity, barrier properties.
- Medical and hygienic devices: Controlled release of drugs, antimicrobial compounds.
- Biosensors, displays, electronic devices: Devices that change structurally under the influence of an external field, and visionary but not impossible, preparation of semiconducting devices on fibre surfaces.
Project Results:
1.3.1 Targets/demonstrators defined by industrial partners
Innovia's demonstrators:
- Moisture barrier of <30 g/m2/day measured at 38°C and 90% RH.
- Heat seal strength of >200g/25mm which are maintained under moist conditions.
Litija's demonstrators:
Surface modification of viscose fibres applying nano-particles in a wet finishing process. The new high-value viscose fibres have to be mechanically and chemically resistant to all mechanical and chemical textile processing and should possess the following properties:
- Anti-microbial treatment (bacterial reduction of more than 95%).
- Protection against UV irradiation.
Mondi's demonstrators:
Office papers with enhanced optical properties, which are defined as following:
- High-yield pulp office paper with same aging resistance and mechanical strength as conventional wood free office paper.
- 20% reduction of yellowing after 500 W irradiation by xenon lamp.
- 75 g/m2 office paper with same opacity as conventional 80 g/m2 office paper.
- Increase of mechanical strength significantly (tear resistance and stiffness) by 10%.
X-Flow's demonstrators:
Ultra filtration membranes for surface water treatment to reject:
- Selective removal of endocrine materials from urine (hormones from anti baby pill, DNA, RNA, protein fractions). Concentrations of endocrine disruptors and other micropollutants are demanded by regulations to be at 5 ppb or even 1 ppb.
- NOM (Natural Organic Matter) ranging from molecular weights of roughly 100-1000 Da and from hydrophilic to hydrophobic nature.
Scientific hot topic demonstrators:
Partner 4 (University Jena) has developed amino cellulose surface coatings building self-assembled monolayers with excellent properties for enzyme immobilization.
The project has generated ways to create new, nano-structured materials with specific functionalities based on renewable polymers. The envisioned surface modifications were achieved applying interaction processes without heavy chemistry:
- Incorporation of specific anionic or cationic groups (for selective interactions);
- Introduction of antimicrobial groups;
- Introduction of specific adsorption sites or groups (DNA fragments, protein receptors);
- Introduction of specific surface properties such as hydrophobicity, low surface energy, barrier properties via layer by layer structures (water vapor, oxygen barriers);
- The possibility to create cationic, non-charged and anionic membrane surfaces depositing likely charged polysaccharides on a cellulose membrane surface.
Specific nano particles were embedded into the polysaccharide coating to achieve:
- Antimicrobial activity (Ag, Cu, ZnO, Ag, Pt particles) ;
- Optical properties (TiO2, ZnO, silica nanoparticles);
- Flame retardency (layered silicates, clay nanocomposites);
- Catalytic devices.
In order to improve the understanding and enlarge the material basic for the demonstrators a variety of PS derivatives and stabilized nanoparticle were synthesized and combinations of both, the PS functionalities and nano ' particles was prepared. These combinations had all together the common ground of similar chemical and physical basic processes and technologies.
Together with the industrial partners the technologically promising combinations were defined at the project stage 'final selection of topics', focused on the 4 main targets (demonstrators), see Figure 3. Due to the fact that numerous approaches were possible, a very restrictive selection process was needed to focus on the defined targets. The selection criteria were defined in accordance with the industrial partners. Criteria were a combination of the propability to reach the technological goals (risk of technology failure and unexpected problems), market size, commercial benefits and estimated time to market as well as environmental aspects defined by LCA. The target was to bring these demonstrators towards a pilot scale production and application.
In addition, beside these technologically very demanding but realistically achievable targets we defined that additional visionary target(s) not in the industries primary focus but of demanding scientific and technological properties with future industrial applications might also be developed.
1.3.2 Project organization
The research and development activities were organized (Figure 4) in the following work packages:
- WP1: Chemical functionalisation of PS.
- WP2: Nano-paticle systems: Creation, dispersion, characterisation and interaction with dissolved polysaccharides.
- WP3: Interaction of functionalised PS with cellulose matrix and embedding of nano-particles into/onto PS coated cellulose matrices.
- WP4: Development of surface functionalisation of films and membranes.
- WP5: Development of surface functionalised fibres and non wovens.
- WP6: Life cycle assessment.
- WP7: Management.
- WP8: Dissemination.
1.3.3 S&T results
1.3.3.1 WP1: Chemical functionalization of PS
Objectives
1. Dissolution of cellulose and other polysaccharides in different solvents as well as characterisation of the solutions obtained.
2. Chemical and physical functionalization of cellulose and other polysaccharides.
3. Transfer into the pilot scale.
Tasks
1. Dissolution of cellulose and other polysaccharides in different solvents, solution characterization and properties. Goal was to prepare, to characterize and to understand cellulose-starch mixtures in ionic liquid in the fluid and solid state.
2. Synthesis of polysaccharide derivatives with different functional groups, degree of substitution and partially region-selective derivatisation.
3. Synthesis of cationically charged cellulose moieties and coating on polysaccharide to improving the binding properties of antibody-proteins on surfaces (e.g. glass).
4. Scale up of new functionalized cellulose moieties.
Significant results
- Cellulose and starch coexist without any phase separation in EMIMAc as far as total polymer concentration used is far from their dissolution limit. Cellulose- and cellulose/starch hybrid-films were prepared using ionic liquids as solvent. The starch was found to be inhomogeneously distributed in the hybrid-films. Their permeability dropped with pressure increase.
- Several new cellulose derivatives providing different functionalities were synthesized with degree of substitution and regio-selectivity.
- Cellulose-i?-lipoate sulphate was found to stabilize gold nanoparticles. Single hollow fiber modules provided by X-Flow have been coated with 6-deoxy-6-azido/aminopropargyl-carboxymethyl cellulose ' evaluation at X-Flow revealed significant loss of permeability.
- The binding of proteins on glass and polymer surfaces was improved using cationically charged cellulose moieties. After the successful antibody immobilization on the amino cellulose modified layer, these layers were used for a real-time CRP (antigen) detector system.
- Scaled up products of specific polysaccharide compounds are available.
1.3.3.2 WP2: Nano-paticle systems: Creation, dispersion, characterisation and interaction with dissolved polysaccharides
Objectives:
1. Synthesis of metal, metal oxide and semiconductor nanoparticles.
2. Adjustment of the nanoparticle chemical composition, size, shape and dispersity.
3. Optimisation of nanoparticle physical properties for individual demonstrators.
4. Preparation of stable nanoparticle dispersions in dissolved PS and derivatised PS.
5. Optimisation of nanoparticle porosity in terms of nanopores and pore size dispersity.
6. Study of dispersed nanoparticles interactions with cellulose and PS (modified/raw).
7. Development of robust models of real nanoparticle-polysaccharide interactions.
Tasks and participating partners
1. In-situ preparation of stable TiO2 (TiO2/SiO2) ' cellulose derivatives colloidal solutions and preparation procedure optimisation for in-situ deposition on cellulose surfaces (P5).
2. Synthesis of Ag-cellulose derivative nanocomposites for antimicrobial fibres (P1, P2).
3. Nobel nanoparticles for hormone removal (P5, P8, P9).
4. Preparation of aqueous nanoparticle suspensions in larger scale (P8).
5. Enhancement of understanding of the nanoparticles dispersion process in cellulose solutions and preparation of cellulose acetate nanoparticles (P1, P3).
Significant results
- The process to stabilise aqueous dispersions of TiO2, Ag and metal nanoparticles using water-soluble polysaccharides was optimised. Polysaccharides can be used as reducing agents as well as stabilisers at low temperatures in cost-effective, environmentally friendly reactions. These dispersions of porous nanoparticle/PS nanocomposites are stable at room temperature for many months and sometimes for more than one and a half years.
- New synthetic methods to prepare colourless Ag nanoparticles and in situ Ag nanoparticles using microwave irradiation were developed and used for Litija's demonstrators to produce fibres with significant antibacterial properties against resistant bacteria, such as MRSA, found in hospital environments, for example. The size and shape of the nanoparticles could be controlled from very small (app. 10 nm) to very large (app. 600 nm).
- Microporous Pentair X-Flow membrane WP4 demonstrators coated with PS-stabilised Ag nanoparticles from aqueous colloidal solutions showed significant antibacterial activity for water remediation.
- An environmentally friendly microwave synthesis of Ag nanoparticles in aqueous solution was developed, whereby the synthesis reaction time was reduced by factor of 60.
- A route to synthesize cellulose acetate nanoparticles with different surface functionalities was developed
- An environmentally friendly ZnO nanoparticle method of preparation in aqueous solvents was successfully up scaled. These platelets have been used for Litija's demonstrators to produce fibres with significant antibacterial properties.
- Reduction of the undesired TiO2 photocatalytic activity was achieved by coating the nanoparticle with APTES.
- Core/shell titania/silica nanoparticles were prepared and deposited using a layer-by-layer approach on Mondi's demonstrator paper that became whiter, brighter and more stable to degradation by sunlight.
- Preparation of carbon black sub-micro particles in aqueous cellulose solutions. Microporous membranes (X-Flow demonstrator) coated with Pd-stabilised Ag nanoparticles from aqueous colloidal solutions showed significant heterogeneous catalytic activity for continuous-flow reactions in water.
1.3.3.3 WP3: Interaction of functionalised PS with cellulose matrix and embedding of nano-particles into/onto PS coated cellulose matrices
Objectives
1. Preparation, characterization and activation of reference matrix materials (cellulose, films, fibres, membranes).
2. Adsorption-desorption of dissolved derivatised Cell and PS (modified and raw) on cellulose matrices.
3. Embedding/immobilisation of nano-particles on original and coated Cell surfaces.
4. Characterisation of Cell ' nano-particles compounds.
5. Modelling of the adsorption-desorption process.
6. Transfer into small scale pilot scale.
7. Scientific hot topic ' Microfluidic protein detection system.
Tasks
1. Study of adsorption of polysaccharide stabilised nanoparticles on cellulose model films and real surfaces.
2. Antifouling / antimicrobial coatings on membrane substrates.
3. Model coating development to improve barrier properties.
4. Scientific hot topic ' Microfluidic protein detection system.
5. Cellulose matrix pre-treatment and in situ formation of Ag nanoparticles.
6. Modelling of adsorption process in molecular and micrometer scale.
Significant results
- General know-how according the NP adsorption process, its dependence on ionic strength, pH and NP stabilisation agents.
- Coating formulation of inorganic oxide particles (i.e. TiO2), prepared in a solution of a polysaccharide (i.e. CMC), can serve as an efficient modifying agent, with which new properties and functionalities can be imparted to different cellulose matrices.
- It is the dispersing and stabilizing ability of a cellulose derivative solution that ensures the maximum effect provided from active particles ' insufficient stabilization would inhibit their activity. In addition to that, stable polysaccharide-based particles' dispersions act as a carrier and adsorbing driver for homogenous deposition of inorganic particulate matter on surface of various cellulose substrates.
- Activation of cellulose fibres for enhanced particle synthesis and formation of firmly-attached coatings.
- In situ preparation of Ag nanoparticles on fibre surfaces causes strong deposition withstanding several washing procedures.
- Molecular modelling of the cellulose surface, their interaction with water molecules and oligosaccharides using semi-empirical and ab initio methods.
1.3.3.4 WP4: Development of surface functionalisation of films and membranes
The demonstrator deliverables in WP4 are twofold and are partner specific. The deliverables for X-FLOW BV have been achieved and not only substantially surpassed are somewhat in advance of that expected at this point in time.
The deliverables for Innovia Films were finally also achieved. More effort was needed due to the need to produce model films with consistent properties that enables the transfer of the laboratory work achieved in WP2 and WP3. A pilot plant production of Cellophane films with increased hydrophobicity and decreased water vapour transmission was obtained.
Cellulose acetate hollow fibre membranes with antimicrobial coating and enzymatic hormone degradation
X-Flow hollow fibre standard membranes were coated with hydrophilic silver containing sol-gel material. The permeability of clean water was investigated with flow tests. The morphology and elemental composition of the coated membranes was investigated with scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDX).
The chemical stability of the coated membranes against sodium hypochlorite cleaning was investigated. In addition long term filtration experiments with surface water were performed. EDX and SEM measurements revealed a successful immobilisation of silver in the membrane structure (Figure 23). Long term filtration tests showed that low amounts of Ag have no negative effect on the life time of the membrane.
Up-scaling on fibre modules (RX300 modules) of the in situ coatings with silver was performed (Figure 24). Again SEM, EDX and flow tests were performed; the chemical resistance was investigated by a sodium hypochlorite treatment.
It could be shown that in situ coating with silver reduces the clean water permeability of fibre modules. Also the chemical stability is reduced when silver is present in the membrane. Nevertheless silver was successfully immobilised inside the membrane structure. Therefore the silver has a potential application as antimicrobial coating.
Cellulose acetate hollow fibre membranes were successfully coated with SiO2. EDX studies revealed the presence of silicon over the entire membrane structure. Flow tests with clean water showed a reduction of the permeability even though no changes in the pores size of the membrane could be observed.
Cellulose acetate hollow fibre membranes were successfully coated with SiO2. EDX studies revealed the presence of silicon over the entire membrane structure. Flow tests with clean water showed a reduction of the permeability even though no changes in the pores size of the membrane could be observed.
For the increase in hydrophilicity and improvement of anti-fouling properties, model surfaces of cellulose acetate and single hollow fibre membranes were coated with multi-layers of Chitosan and carboxymethyl cellulose. The controlled release of the multi-layers for a cleaning of membranes was investigated. Multi-layer growth and controlled release were evaluated by optical thickness; contact angle measurements atomic force microscopy and scanning electron microscopy.
The polysaccharide multi-layer built up could be controlled with the pH value of the coating solutions. In general, thicker layers are produced at lower pH values. Layers with a thickness of several hundred nanometres can be obtained. A successful removal of these coatings can be performed under defined washing conditions. This opens the way to generate anti-fouling coatings which can be regenerated.
Further investigations on the coating conditions of membranes are necessary. The long term anti-fouling properties of the membranes with surface water are under investigation. For testing the antimicrobial activity of surfaces, a combination of methods was developed. Electron microscopy, fluorescence microscopy and real time PCR were successfully combined to investigate bacterial growth on surfaces. Chitosan/CMC coatings on cellulose acetate surfaces turned out to be very efficient in inhibiting bacterial growth. These coatings are therefore used to create anti-fouling layers on cellulose acetate surfaces.
For the enzymatic digestion of endocrine compounds horse radish peroxidase enzymes were successfully isolated from pichia pastoris fermentation cultures. Purification was performed with anion exchange and size exclusion chromatography. Pure enzymes with high activities and the ability to digest estrogens were obtained. Those enzymes are covalently immobilized on layer coated CA membranes and are tested using medium sized pilot membrane modules.
Figure 25 shows the resistance of the membrane versus the filtration time of real surface water at the Twente canal in the area of Enschede. The surface water is still standing canal water, which has a high organic load. The high organic load mostly fouls the membrane dramatically and is therefore a good indication if a low fouling membrane is present or not.
The graph shows that our standard membrane (blue line) starts similar to the in-situ Ag coated membranes. This also indicates that the permeability (resistance) did not change after coating the Ag on the membrane. During filtration time, fouling is built up on top of the membrane and with that the resistance of the membrane increases. The standard membrane lies slightly higher than the coated membrane, which indicates that the coated membrane fouls slightly less than the standard membrane. This trend can also be seen after a first chemical backwash, where all the fouling material is removed from the membrane and the resistance is going back to zero. Also after all other chemical backwashes, the coated membrane stays below the resistance of the standard type of membrane.
The production of large cellulose acetate and cellulose acetate butyrate flow modules was performed (Figure 26). The influence of the wall thickness of the membranes on the formation on voids was studied and process optimisation led to void free fibres. Fibre bundles of 300 mm length were assembled to a final filtration unit in PVC housing tubes.
Performed pilot plant production and testing:
- Up-scaling of membranes and modules
A new type of more chemically stable cellulose acetate derivative (cellulose acetate butyrate) is used to produce new type of ecological friendly membranes for the surface functionalization of these membranes using embedded nano-particles. The problem by up-scaling this production process is the formation of perfect sponge like-macrovoid free structures. Thus it is now possible to produce for X-Flow membranes from renewable sources. Intermediate pilot plant modules are produced with a 300 mm long tubular housing. After spinning of sufficient amounts of hollow fibre membranes from cellulose tri-acetate (CTA) and cellulose acetate butyrate (CAB) under good circumstances to prevent macrovoid formation, production of the first large pilot module could be started
- Coating of layers and the influence on membrane properties
The enzyme or nanomaterial has to be coated on top of the membrane sub structure to get fixed on the membrane. Therefore a layer by layer coating technique was developed with X-Flow and the University of Graz.
The industrial coating procedure consists of five different steps (Activation of the membrane surface, Carbomethoxycellulose (CMC) coating, chitosan coating, 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide) (EDC) step, enzyme step). The influence of this coating on the membrane performance should be limited as much as possible to maintain the full filtration performance of the membrane. Parameters for this performance are mainly water permeability and mean flow pore size (MFP). The influence of the coating layer on these parameters
- Testing of new materials
- Low fouling membranes (Demonstrator 1)
- Immobilization of HRPO enzyme for hormone degradation (Demonstrator 2)
- Transfer into larger pilot scale and field test
- Recent field tests on low fouling behavior membranes (Demonstrator 1)
- Field tests on endocrine disrupter removal membranes (Demonstrator 2)
Improvement of barrier properties of Innovia regenerated cellulose films
Two different systems were applied in the pilot production trials:
- 100% pre-condensed water borne SolGel was a solution supplied by CHT and was place in the final Additive bath of the casting process before the heated cylinders. A new coating smoothing arrangement as well as coating return was designed to enable even lay down of the coating. Laboratory tests implied that the results should be in the order of 20g/m2/day for water vapour.
- Ionically stabilised polyelectrolyte bi-layer with exfoliated Montmorillonite from Graz University used the final three baths having a wash bath in between the two application baths. Unlike the laboratory experiments multiple dipping was undertaken in each bath, in part due to the residence time required for mono-layer coverage. To simulate the pilot plant conditions some lab experiments regarding dipping time and concentrations of the single components were performed. An overview of these experiments is shown in Figure 27.
The higher the concentration of the clay suspension the higher are the barrier properties, the reduced dipping time of 10 seconds gained even better barrier properties. These results represented the final proof that this coating system can be transferred to the pilot plant.
In order to condense the multiple coating steps of the LbL technique, another approach was used. Here the clay suspension and the polymer solution (polyvinyl alcohol) were blended prior the coating procedure. A threefold application of these coatings lead to similar results regarding the barrier properties like a 20 bilayer coating using the LbL approach. Here too, a drastic reduction of the dipping time (10s) did not lead to worse barrier properties.
Therefore both approaches were used to perform pilot plant trials.
The pilot plant itself (Figure 28), consist, like the production line, of a spinning bath, several bathes to functionalize and purify the film and of a dryer at the end of the line. The dryer consist of hot rollers (90 ?°C) which are heated by hot steam. The film is drawn through the line by rollers, which feature a certain surface structure to prevent creasing of the film. In the pilot plant usually films with a width of around 30 cm are used and the film runs with a speed of 5 m/sec through the line. Since we also applied multiple coating steps, the film was winded up after the dryer and run through the line again. So in total 3 pilot plant trials were performed: one with LBL technique (5 bilayers); one with condensed LbL technique (3 layers) and one with the CHT coating (1layer). From a technical point of view the transfer of the coating to pilot scale worked out fine. The results of the trials are shown in Table 3.
All coating approaches lead to very similar results concerning their barrier properties to water vapor. They are all in the range of 400 g/m2/day. Even though the goal of 30 g/m2/day was not achieved, the developed coatings have a lot of potential, since there is further room for improvements from the pilot production to large scale production. As stated before, the transfer of the coating systems from the lab scale to the pilot plant scale worked fine. Furthermore it has to be noted, that each of the applied coating systems uses water as solvent.
Significant results:
- The X-Flow demonstrator 1 (ant-fouling) is 100% completed. Up-scaling is done, new materials have been tested and further developed with the universities and the best results were transferred into pilot scale and field testing.
- Results from the field tests look promising, and the development for demonstrator 1 is close to the market introduction.
- Although the results on endocrine degradation look very promising (Demonstrator 2), the market introduction will need more detailed research to evaluate the potential of this promising technique.
- A patent application is under preparation together with the University of Graz.
- Work for the Innovia Films demonstrator 3 has shown promising results with barriers being achieved advanced to the barrier products produced by Innovia.
- The developed barrier coatings are biobased and applicable in aqueous systems.
1.3.3.5 WP5 - Development of surface functionalised fibres and non wovens
Litija's demonstrator
Fibre modification to achieve anti-bacterial (AB) properties
Standard modal fibres were selected for the surface modification according to innovative procedures developed in WP1, WP2 and WP3 of in-situ synthesis of nano silver particles immobilized on the fibre surface. The basis of this new procedure is optimized swelling of the fibre, which works as a reduction agent.
For the exhausting process for fibre finishing standard equipment was used to deposit the AgNP in and on the fibre. The in situ procedure does not require any additional thermal fixing procedure.
The developed procedure of the in situ Ag-particle synthesis gains antimicrobial fibres ensuring the presence of active Ag particles in the interior and exterior of the fibrous substrates. The surplus Ag particles that are formed in the treatment bath are stabilized by dissolved surface-located amorphous fibre fractions. Left-over treatment solution is therefore not regarded as a waste product to be discarded, but can be used as useful side-product.
Two types of yarn were produced in different blends:
- 100% CMD Modal AB (C-2011)
- 50% CMD Modal std / 50% CMD Modal AB (ML-2031)
During the spinning process an even distribution of the AgNP was achieved, the concentration depends on the yarn type. The quality parameters of the yarns show, that the modified modal fibres have completely adequate processing properties for spinning, which also results in sufficient physical parameters of the yarns with no regard to whether used in 100% or as blend with other fibres. Additionally, the yarn was twisted to determine if the AB modified modal fibres are suitable for blending with other chemical fibres from synthetic polymers. The results are positive.
Finally the fibres were knitted and T-shirts were produced. The results on the final product confirm that the 25% share of AB modified modal fibre assures sufficient antibacterial activity. The practical utility of the final products in domestic maintenance was also test with produced T-shirts. The final product did not show any negative aspects compared with the standard material.
Mondi's demonstrators
- Successful production of high-quality lab demonstrators containing 50 % chemo-thermo mechanical pulp CTMP and a slight mineral coating.
- Efficient colour shielding of commercially produced dyed paper upon exposure to UV light with application of polysaccharide based coatings (lignin) and implementation of lignin-calcium carbonate complex-powder into a starch slurry.
After exposure of reference and coated paper samples to sun (5 days), we see a clearly the effect of UV radiation on not protected samples. Colour appearance and lightness increased significantly with simultaneous pronounced decrease in chroma (Figure 30).
The Mondi demonstrator was not produced on large scale due to no clear competitive cost advantage due to actual pulp prices (shortage of CTMP).
Significant results
- In-situ modified modal fibre: for the efficient antibacterial activity (which is set at higher than 98% reduction of bacteria on textile, which undergone 10 washing cycles) the minimal share of AB modified modal fibres is 25%.
- The AB modified fibres can be blended with all natural and synthetic staple fibres.
- The process was implemented under industrial conditions (100 kg of AB modified modal fibres or more than 200 T-shirts).
- Successful production of high-quality lab demonstrators containing 50 % CTMP and a slight mineral coating.
- Efficient colour shielding of commercially produced dyed paper upon exposure to UV light with application of polysaccharide based coatings (lignin) and implementation of lignin-calcium carbonate complex-powder into a starch slurry.
- Patent application ('Antimicrobial Cellulose Material and Process of its Production').
1.3.3.6 WP6: Life cycle assessment
Objectives
1. To conduct Life cycle assessment (LCA) of P13 (Mondi) demonstrator, high yield pulp printing and writing paper, and P9 (X-Flow BV) demonstrator, hormone removal membrane. This is conducted by analyzing all synthesis routes of the NP of P13 (Mondi) and P9 (X-Flow BV).
2. To conduct an assessment of waste management of Surfuncell demonstrators (P9, P11 and P13) and report the findings in the form of a deliverable report.
Tasks
1. Collection of life cycle data of existing conventional product processes of P13 and P9.
2. Collection of data of all planned synthesis routes of P13 and P9 demonstrators from research partners.
3. Screening study of all planned synthesis routes of P13 and P9 demonstrators.
4. Detailed analysis of final synthesis routes of P13 and P9 demonstrators already chosen for up-scaling.
5. Collection of scale up data for analysis.
6. Collection of life cycle data of existing conventional processes P11.
7. Collection of data of all new synthesis routes of P9 and P11 demonstrators from research partners.
8. Screening study of all new synthesis routes of P9 and P11 demonstrators.
9. Detailed analysis of final synthesis routes of P9 and P11 demonstrators already chosen for up-scaling.
Waste management report
A waste management report was established to help the producers to devise better product life cycles and end of life strategies by integrating life cycle waste management aspects during product design and development stage. This report can also help producers to avoid business risks from potential EU legislations due to awareness and, consequently, better prepares these companies to create competitive advantage in the market place with early mover advantage. It is presented in the extended project documents.
Hormone removal membrane demonstrator by X-flow
Figure 35 shows that NREU (non-renewable energy use) of membrane and wood based GAC process are comparable but GHG emissions of membrane processes are lower than GAC. These are also membrane system's design boundaries to be fulfilled in order to ensure lower environmental impacts than GAC processes operating anywhere in the world.
Cost analysis of Surfuncell demonstrators
In the absence of commercial scale production and for confidentiality reasons, cost indices are presented here. These cost indices were estimated by our industrial partners. In two cases the cost of Surfuncell demonstrator is somewhat higher than the reference. However, as pointed out by one partner, Surfuncell products offer new functionalities, hence justifying the cost increase.
Significant results
- Improve resource efficiency: The resource efficiency of silver during T-shirt manufacturing is 60% which can be greatly improved by increasing the fastness of Ag NP on fiber surface.
- The process waste generated during different processes should be reduced and especially downstream processes should be given more priority.
- Limit the concentration of NP in the product: define the exact concentration required to meet the intended functionality during the product's useful life time.
- Design products that emit large particles or aggregates which will be easy to filter and reuse: Every NP is functionalized to meet its function.
- For silver NP containing products, it is important that excessive or unwanted silver ion release should be avoided throughout product life cycles since silver ions pose a 10,000-fold higher risk than silver NPs.
- Clearly label the products with NP characterization.
- Design products with end of life in mind: In order to avoid regulatory risks related to future REACH legislation or end of life legislations such as WEEE, it is recommended to Surfuncell companies to carefully consider the end of life (disposal, recovery/recycling) of their products before market entry of the products.
- Opportunity to invent new products to avoid waste management problems: The challenges posed by NPs during different product life cycles stages provide various business opportunities. Methods could be developed to recover aggregated NPs from activated sludge of WWTP.
Potential Impact:
1.4 Potential impact and main dissemination activities and exploitation of results
The socio-economic impact and the wider societal implications of the project Surfuncell are mainly reflected by the commercial demonstrators, which are clearly the most important outputs of the Surfuncell programme. These demonstrators should have a very real socio-economic and societal impact in many areas of the world as they will be brought to market and commercialised on a major scale.
Due to the fact that biobased materials are transferred into high value products impacts in terms of energy and non-renewable resources reduction can be clearly foreseen. The biobased materials are available in almost all regions. The developed high value products are partially connected with high tech instrumentation or large scale production devices but a good part can be produced with standard equipment. Both offers the possibility that these products will create or maintain jobs in even less developed regions. The research and development resulted also in high tech and high value products which will have some impact to the job situation in Europe.
1.4.1 Direct project related impacts
1.4.1.1 Basic research
The science in the field macromolecular chemistry, organic chemistry, nano-particle synthesis, material science, biotechnology was clearly promoted by the cooperation in this interdisciplinary project. New insight was created in these fields leading to a deeper understanding of basic processes in terms of functionalization of polysaccharides, the synthesis, formation and stabilization of nano-particles, the interaction at the liquid solid interface and of molecular aspects of the adsorption process and the involved driving forces.
The know-how development went far ahead of the focused direct application. Basic know how for further development project was gained mainly applicable for high value products.
Outcome
- Papers in peer-reviewed journals: 20 published, 1 in press, 4 under review, 5 in preparation.
- Lectures / posters at conferences: 80.
- Thesis/ Diploma: 13 finished, 5 under preparation.
1.4.1.2 Applied research
Multidisciplinary projects also integrating companies contribute always to the enlargement of all persons involved. The academic partner gain insight and understanding of the problems and limits in production process, the industrial partner develop a deeper understanding of the physical and chemical process background fostering further developments.
The intensive cooperation allowed the process development to be very focused on the industrial partners demand. Combined with life cycle assessments of the standard products and comparison with the new development decisions were made about development routs. The well defined R&D activities with clear targets and time lines necessary in such cooperation enforce a well organized work style from all partners. This is a great opportunity especially for young researcher to become used to the demands of an international development proposal.
Outcome
Workshops/trainings: 5 trainings were held during the project life-time.
1.4.1.3 Pilot plant production of demonstrators
The development reached the target of pilot products for all planed applications. Different levels of technology transfer were reached.
The industrial partner Litija, producing yarns achieved a product and a process almost transferable to large scale production.
The industrial partner Innovia, producing packaging material, achieved a new coating device able to replace synthetic polymer coatings connected with heavy chemical processes. The innovative product was already produced at pilot plant scale and shows interesting property improvements. Further improvements will extend the application range.
Drinking water purification membranes were developed together with the industrial partner X-flow. The company itself developed new membrane materials, the research partner processes to avoid biofouling and to degrade enzymatically hormone and hormone degradation products in drinking water. Pilot scaled devices were produced and are under test.
The paper producer Mondi could also develop in this cooperation a new paper coating with the possibility to create office paper with reduced demand on basic material, process chemicals and energy. This product was developed to a large laboratory scale and shows all demanded properties.
Beside the targets (demonstrators) defined at the project start several technologically 'Hot topics' were recognized.
Outcome
Products almost ready for production: 2 demonstrators (i.e. antimicrobial fibres and cellulose acetate hollow fibre membranes) are already produced in several 100 kg scale and transferred to potentially final products (new membranes, mixed yarns and T-shirts).
Products in pilot scale trial: 3 demonstrators are in this stage. The antimicrobial coating and the hormone degrading enzyme layer for water purification membranes, and the high barrier cellulose based packaging material.
Product in small scale trial: Paper sheet were already produced from high-quality chemo-thermo mechanical pulp. The demanded UV shielding and paper strength was demonstrated.
1.4.1.4 Industrial partners
The Surfuncell programme has provided financial stability and sustainability to NanoMePS, which is now on a sound financial footing and has employed a further chemist to boost its research and manufacturing capability. The Surfuncell programme has expanded the product portfolio of NanoMePS and provided it with know-how and expertise in the water-based synthesis of stable solutions of nanoparticles rather than using VOC based manufacturing of nanoparticle powders, which are much more difficult to process and which are much more of a concern from a health perspective.
1.4.1.5 Individual work packages
WP1, WP2, WP3 and also WP6 are essential pre-cursor steps to and facilitator of the later work packages 4 and 5 without which the demonstrators could not be realized.
Work package 1
The research work in WP1 was directed towards the use of polysaccharides from the pool of renewable resources to design highly engineered chemical compounds based on polysaccharides. Moreover, environmentally friendly solvents, in particular ionic liquids were applied as solvent for shaping and functionalization of the biopolymers. The polysaccharide-based products may impact the material properties at a low amount, i.e. as thin films. e.g. and thus they are used in the context of nano- and microtechnology.
Work package 2
The development of a portfolio of simple and scalable 'green synthetic methods' to produce stable colloidal dispersions of cellulose-stabilised organic, metallic and semiconductor nanoparticles using water as the solvent and cheap, available reducing agents, sometimes the cellulose derivatives used to stabilise the nanoparticles in solution, and cellulose derivatives as the capping and stabilising agents is of clear economic and societal relevance and commercial importance. The development of generally applicable environmentally friendly methods to prepare stable aqueous dispersions of a very wide range of metallic and semiconductor nanoparticles, which can be used in a very simple way to coat the outer surface of cellulose fibres, membranes, filters, etc, to produce a whole series of products based on renewable resources is of general importance to the development of nanotechnology and its uptake as a major manufacturing process. These methods should improve the efficacy and efficiency of the nanoparticles by their being concentrated on the surface in a thin film of cellulose-stabilised nanoparticles of the cellulose-based supports, while at the same time significantly reducing the amounts of nanoparticles required to achieve a given effect.
Work package 3
Integrating the basic materials and know-how provided by WP1 and WP2 towards compounds in laboratory scale. The portfolio of new polysaccharide derivatives providing a variety of functionalities, new cellulose dissolution processes and a large number of stabilized nanoparticles were the basement for the successful development of a variety of surface modification processes and coatings. Based on LCA data environmentally friendly process routs were developed for these surface modification / surface compounding processes. Processes as well as coating formulations are applicable in a far wider area as approached during this research program. The modelling processes performed provided deeper insight into the structural and energetic processes on molecular level.
Work package 4 and 5
The impact of these work packages is self-evident. Several demonstrator products were produced in pilot scale or pre-pilot scale proving the correctness of the basic strategy, of the developed new materials and process routs.
Work package 6
The life cycle assessment performed during the project on classical and new materials gave important advice for the definition of proper process routs with a low environmental footprint.
1.4.1.6 Commercial and societal impact
The commercial and societal benefits of this new approach are self-evident. The ability to tailor the size, shape and polydispersity of the nanoparticles, for example large nanoparticles with a diameter above 100 nm, and the ability to firmly fix these to the surface of naturally occurring and renewable cellulose derivatives using a new developed tool box of functional polysaccharide derivatives offers numerous applications and a wide field for new business opportunities far beyond the frame of Surfuncell.
The gained know how will also clearly provide tools to control and limit the toxicity, take up and proliferation of these nanoparticles in the environment and provide very significant the overall life-cycle benefits. Such considerations are important limiting factors in the general uptake of nanotechnology as a mainstream area of manufacturing.
The importance of all work packages is reflected in the economic and societal relevance and commercial importance of the demonstrators emanating from WP4 and WP5.
1.4.1.7 Gender aspects
Research, development and organization work was carried out from both female and male persons employed at industrial partners, researcher, PhD students and students.
1.4.2 Not directly project related impacts
1.4.2.1 Creation of research and technology transfer network
The essential task creating a European research area is the formation of networks performing multidisciplinary research and providing the transfer of research results into innovation. These networks are speeding up this very crucial transfer steps and provide so technological leader ship and new business, partially performed by SME founded by persons out of the research community.
1.4.2.2 Education of young scientists involved into the project
The exchange provided during the project with the industrial partners and other research groups is an essential extension of young persons education and reparation for the demands of their future jobs.
1.4.2.3 Education cooperation
Beside exchange also fruitful education cooperation was fostered. This included mutual lectures, lessons, courses with contribution of experienced lecturer and also the young persons involved including the definition and development of new research projects. Integrated into this cooperation was the network of excellence EPNOE, the Marie Curie project STREAM and the European master program TONI.
1.4.2.4 Exchange of R&D persons
The exchange of R&D persons between research groups an especially between research groups and industrial partner enlarged their degree of understanding and their possibility to understand the other sides needs and limits. This is an important experience and prerequisite for further technology transfer projects.
1.4.2.5 Impact on hosting universities and research organisations
The Surfuncell project has allowed the universities to expand their interests and expertise in synthesis, purification and characterisation of high-value added, functional polysaccharide derivatives, nanoparticels and organic/inorganic hybrid composite materials. Base on this they have excellent chances to further develop new materials in the frame of national and international projects. The project groups will continue to work on Surfuncell related research projects. The financial support allowed the purchasing of new research equipment partially financed by project money. The programme had als an impact on teaching because of the teachers' exposure to applied and industrial problems. The gained experience will be integrated into their teaching topics.
1.4.2.6 Centre of excellent PS research & technology transfer
All person involved build a temporary centre of excellence in this R&D area. In this case this will be prolonged and integrated into the European Polysaccharide Network of Excellence (EPNOE). The gained know how and networking will be further utilized in this frame.
1.4.2.7 Recognition in scientific and industrial world
The successful performance in such an international research project provides to all partner a positive recognition in the scientific as well as in the industrial community. Especially young person successfully active in such a network are able to use this for further promotion of their career.
1.4.3 The socio-economic impact and the wider societal implications
- High value products were developed and brought toward a pilot scale production. The future entering into the market will have positive impact on the employment situation of the companies.
- The early market penetration by the companies is fostered by the dissemination activities performed during the project.
- Improvement of life quality: The product developed by X-flow, Innovia and Litija will have direct influence the quality of life of many persons. The water purification membranes reducing the hormone pollution of drinking water, the biobased packaging material because of its absolute non toxicity and the antimicrobial finished textiles in aspects of person hygiene and hygiene in public areas.
- Improvement of environmental conditions: The biobased high-value materials will be produced following process routs which were selected via LCA in order to provide less deposition of synthetics materials, less consummation basic materials, energy and land.
1.4.4 Main dissemination activities and exploitation of results
The research carried out in Surfuncell generated considerable output which was put forward to industry groups. As already foreseen at the start of the project, industrial partners will produce new equipment and as such exploit the project's results.
Part of the research and development work performed in Surfuncell was incorporated directly in prototypes for future commercial production. Despite the fact that in some cases additional development and validation work will still have to be done, some of the new technologies and products may already be implemented by the industrial partners within the near future after the termination of the project.
Finally, it is foreseen that universities and research institutes will exploit the results by integrating them into their educational and training programmes, allowing more and better qualified engineers completing their master and PhD programmes. The Surfuncell project members University of Graz, University of Maribor, ARMINES, University of Jena, University of Hull and University of Utrecht are such an example which makes use of results in their master and PhD programmes.
As documented above, the focus of Surfuncell was predominantly on research, development, validation, verification, and implementation of technology and products which can be produced and deployed at a European and global level. The technologies and concepts developed were published rather than patented. Consequently, there is one patent application at the moment, and the other one is under preparation. There are, however, quite some several examples of concretely exploitable foreground, the most relevant ones being listed in table below.
List of Websites:
Project Coordinator:
Prof. Dr. Volker Ribitsch
University of Graz
Institute of Chemistry
Heinrichstrassse 28
A ' 8010 Graz
Austria
Telephone:
0043 316 380 5418
E-mail address:
volker.ribitsch@uni-graz.at
Website address:
http://www.surfuncell.eu
1.1 Executive summary
Polysaccharides produced by plants and microorganism are the most abundant biopolymers on earth. They are used by manly as low complex and low value products and their exceptional properties are mostly neglected. These biopolymers are multifunctional and stereoregular by nature, show a large variety of complex structures based on small chemical variations. This projects vision was to contribute knowledge how these specific properties can be utilized more effectively in order to transfer these biopolymers into high value products.
The projects main RTD objective was to create new, smart and bio-based surface nanostructured polymer composites providing high value surface functionalities (mechanical, chemical, selective interaction properties). These new materials should be composed of nano-scaled polysaccharide layers with embedded nano-particles, for the coating of different cellulose matrices. The compounding is restricted to the biopolymers surface and outer layers, providing the 'filler' to the domain where it is required and avoiding the deterioration of the matrix materials mechanical properties.
A multidisciplinary team provided the needed complimentary know how. The integrative work program defined strategic routes towards new materials followed by up-scaling of some results into industrial pilot production. Experimental investigations of the basic principles together with extended modelling have provided the necessary understanding to develop the technologically best candidates towards production. LCA has provided decision making support to choose process routs environmentally acceptable for manufacturer and the society.
Finally 4 from the industrial partner envisaged products and two scientific hot topic were developed towards pilot production stages.
The basic research provided new cellulose derivatives with specific functionalities, new synthetic routs for the save production of different kinds of nanoparticles and allowed to build up an extended know how to produce biobased nanostructured surface compounds.
These innovative products comprise:
- Water purification membranes providing reduced fouling (elongated operating life time) and degradation of hormone residues present in drinking water via immobilized enzymes.
- Cellulose fibres with integrated and stable immobilized silver nanoparticles providing desired antimicrobial properties. These fibres will be integrated into fabrics used in hygienic, public and sports application.
- Cellulose based packaging material with improved water vapour barrier properties. Cellulose packaging material replacing synthetic polymer packaging materials has low resistance against humidity permeation. Non-renewable materials providing these barrier properties can be substituted by a barrier coating using natural compounds.
- High-yield pulp office paper with same aging resistance and mechanical strength as conventional wood free office paper.
- The scientific hot topics develop to demonstrator stages are both high tech cellulose based coatings; one amino cellulose coating for the immobilization of protein receptors and one cellulose coating for the structuring of micro-scaled channels for microfluidic devices and 3 dimensional structures using digital printing.
Project Context and Objectives:
1.2 Summary description of project context and objectives
1.2.1 Project concept and objectives
Polysaccharides produced by plants and microorganism are the most abundant biopolymers on earth. They are used by humans for many purposes beside nutrition. Partially as they are provided by nature and partially derivatized and processed for different purposes as textile or technical fibers, membranes, packaging material and ingredients in food, cosmetics, toilet articles and pharmaceuticals. These biopolymers are multifunctional and stereoregular by nature, show a large variety of complex structures based on small variations of their chemical primary structure. Beside all development made during decades we still make in general no use of their specific and often extraordinary properties. The projects vision was to contribute knowledge how these specific properties can be utilized more effectively in order to transfer these biopolymers into high value products.
The projects main RTD objective was to create new, smart and bio-based surface nanostructured polymer composites providing high value surface functionalities (mechanical, chemical, selective interaction properties). These new materials should be composed of nano-scaled polysaccharide layers with embedded nano-particles, for the coating of different cellulose matrices. The compounding is restricted to the biopolymers surface and outer layers, providing the 'filler' to the domain where it is required and avoiding the deterioration of the matrix materials mechanical properties.
This has several major advantages: the filler is not compounded into the bulk material, the technical process of cellulose matrix production (films, membranes, fibers) can stay unchanged, the deterioration of the matrix materials mechanical properties is avoided and only small quantities of nano-particles are needed to gain the expected / desired effects.
The project is based on new knowledge about the feasibility of coating a solid cellulose surface with soluble polysaccharides (PS) in an irreversible manner due to their chemical similarity offering the interaction by H-bridges and hydrophobic interactions. This is even the case with oppositely charged and derivatized PS as long as they do not have a significant amount of side chains. A further feasibility step proved that the incorporation of nano-particles into this layer is possible if certain conditions are obeyed. The projects target is the development of this strategic route into new materials and the up-scaling of some results into an industrial pilot production state. This comprised the study of these new effects (cellulose/polysaccharides dissolution, structuring with nano-particles and irreversible coating of cellulose matrices) with the aims of understanding and mastering them, the exploration of their properties and applicability and development of the most promising ones of the new materials a pilot scale production process. This concept opens several routes, each with many different applications, to prepare a completely new class of materials:
Nanostructured biopolymer surface composites made of
polysaccharide - coated cellulose with embedded nano-particles
The development of new, innovative biomass-based materials is of strategic importance. Decreasing oil resources, the increase of the global warming and the awareness of European citizens of the need of more eco-friendly products are the major driving forces. The tremendous development of bio-based products, mainly materials and polymers in the Third Counties (Asian, Brazil) and in the USA, is driven by the wide, mainly unexplored or unknown, opportunities of developing new products by chemical manipulation of bio-based materials. If Europe wishes to be competitive and develop its industry, creating wealth and jobs, it has to boost research that can be transformed into new products. This was the aim of our project which is fully in line with EU directives like the Renewable Energy Roadmap, the Biomass Action Plan or the Environmental Technology action Plan.
Accordingly, this project aimed at the development of a new class of sustainable materials with substantially improved technological properties. Several research and technology transfer tasks were defined comprising:
- Derivatize the coating polysaccharides to gain expected functionalities and to dissolve them at the molecular / nano level;
- Prepare and characterize stable dispersions of different kinds of nano-particles;
- Coat the solid cellulose matrix materials with nano-scaled polysaccharide layers;
- Integrate different kinds of nano-particles into this coating;
- Tune the interaction forces to achieve irreversible adsorption or controlled release;
- Generate a deep understanding for the involved physical and chemical processes using different modelling approaches;
- Characterize the properties of the new materials and compared to existing material;
- Scale up the most promising new materials and transfer into a pilot production stage;
- Prove the sustainability of the new materials by life cycle and economic analysis.
The project brought together a multidisciplinary team In order to achieve this, each partner providing different and complimentary know how. It combined the team with the help of an integrated work program starting with fundamental research in order to prove the technological concept, and extend this from laboratory scale via a primary up-scaling into industrial demonstrator systems. Experimental investigations of the basic principles together with extended modelling have provided the necessary understanding to extend it towards production. LCA has provided decision making support to choose process routs environmentally acceptable for manufacturer and the society.
1.2.2 Formation of functionalised biobased polymer compounds using interface processes
Non-soluble polysaccharides, especially oriented moieties like cellulose, exhibit huge surface areas. This creates conditions for strong physical interactions (Lewis acid based interactions and van der Waals forces) with chemically similar compounds. As a consequence, many naturally occurring polysaccharides (PS) adsorb more or less irreversibly on cellulose surfaces. It is also possible to dissolve chemically modified/functionalised PS and to adsorb them from solution irreversibly on a cellulose matrix, providing surface functionalized materials with new mechanical properties. In an additional step a wide variety of nanoparticles can be embedded into this coating layer.
First step is the functionalization of dissolved PS, followed by deposition of a cellulose surface and embedding of nano-particles into this film. In an alternative process rout the nano-particles interact first with the functionalized PS and this assembly is afterwards adsorbed on the cellulose surface. The strong interaction between the adsorbed PS coating and the cellulose matrix is responsible for the irreversible surface treatment.
One key feature of the developed method is, that a wide range of materials can be prepared, opening the way to new functionalized composite materials in an area where so far only a small range of possibilities have been envisaged. Examples of property enhancement are:
- Selective interaction possibilities;
- Improved mechanical, chemical and thermal stability, barrier properties;
- Surfaces providing a controlled release of active substances;
- Surfaces showing tunable properties;
- Catalytic properties based on renewable materials;
- Selective sensor surface;
- Biocompatible medical devices.
The second key feature is that many desired surfaces properties are achievable using sustainable and environmental friendly processing routes turning renewable materials into high-value goods.
The final processing happens exclusively in heterogeneous reaction systems where surface area and interfacial processes play a dominant role. The understanding of physical interactions acting in this heterogeneous systems consisting of functional compounds (soluble polysaccharides, polyelectrolytes, surfactants, pigments and nano-particles) and the macroscopic cellulosic matrix material was improved and the processes finally utilized technologically. The reasons for the processes complexity are the diversity and limited and inherent micro-heterogeneity of natural polysaccharides. Therefor the derivatisation, modification and processing of PS is often difficult and nano-scale structuring is especially complicated. This is to a large extent the reason why more advanced polymer technology is almost exclusively based on petrochemistry.
The transformation of natural polymers, presently used mainly in low-cost, low-added value commodities, into economically and ecologically sustainable high-tech, high added value products is a challenge. Our project provided several ways to achieve this (Figure 1):
- Deposition of chemically modified/ specifically functionalized polysaccharides in (structured) nano-layers on the surface of cellulose matrices (foils, membranes, fibres). The irreversible adsorption of these layers on cellulose is due to their chemical similarity, resulting in the possibility of hydrogen bonding and hydrophobic interactions.
- Incorporation of nano-particles into this surface layer in two ways:
- Dispersion of the nano-particles into polysaccharide solutions and deposition of the formed aggregates onto the cellulose matrix.
- Deposition into the already formed polysaccharide surface layer.
These processing routes are finishing treatments of already shaped renewable polymers rendering them into high-value goods. Preferably aqueous solvents and environmentally friendly processes are employed. Modifications of the matrix materials production conditions are not be necessary. This strategy opened several ways to create new classes of bio materials with tailored functions and properties applicable in the following fields:
- Separation technology: Materials with selective interaction properties (with organic, inorganic and biological compounds), tunable by environmental conditions.
- Technical fibres and foils: Specific surface modification (strength, abrasion resistance, thermal and chemical stability, hydrophilicity/hydrophobicity '¦).
- Improved material properties: Flame resistance, conductivity, antimicrobial activity, barrier properties.
- Medical and hygienic devices: Controlled release of drugs, antimicrobial compounds.
- Biosensors, displays, electronic devices: Devices that change structurally under the influence of an external field, and visionary but not impossible, preparation of semiconducting devices on fibre surfaces.
Project Results:
1.3.1 Targets/demonstrators defined by industrial partners
Innovia's demonstrators:
- Moisture barrier of <30 g/m2/day measured at 38°C and 90% RH.
- Heat seal strength of >200g/25mm which are maintained under moist conditions.
Litija's demonstrators:
Surface modification of viscose fibres applying nano-particles in a wet finishing process. The new high-value viscose fibres have to be mechanically and chemically resistant to all mechanical and chemical textile processing and should possess the following properties:
- Anti-microbial treatment (bacterial reduction of more than 95%).
- Protection against UV irradiation.
Mondi's demonstrators:
Office papers with enhanced optical properties, which are defined as following:
- High-yield pulp office paper with same aging resistance and mechanical strength as conventional wood free office paper.
- 20% reduction of yellowing after 500 W irradiation by xenon lamp.
- 75 g/m2 office paper with same opacity as conventional 80 g/m2 office paper.
- Increase of mechanical strength significantly (tear resistance and stiffness) by 10%.
X-Flow's demonstrators:
Ultra filtration membranes for surface water treatment to reject:
- Selective removal of endocrine materials from urine (hormones from anti baby pill, DNA, RNA, protein fractions). Concentrations of endocrine disruptors and other micropollutants are demanded by regulations to be at 5 ppb or even 1 ppb.
- NOM (Natural Organic Matter) ranging from molecular weights of roughly 100-1000 Da and from hydrophilic to hydrophobic nature.
Scientific hot topic demonstrators:
Partner 4 (University Jena) has developed amino cellulose surface coatings building self-assembled monolayers with excellent properties for enzyme immobilization.
The project has generated ways to create new, nano-structured materials with specific functionalities based on renewable polymers. The envisioned surface modifications were achieved applying interaction processes without heavy chemistry:
- Incorporation of specific anionic or cationic groups (for selective interactions);
- Introduction of antimicrobial groups;
- Introduction of specific adsorption sites or groups (DNA fragments, protein receptors);
- Introduction of specific surface properties such as hydrophobicity, low surface energy, barrier properties via layer by layer structures (water vapor, oxygen barriers);
- The possibility to create cationic, non-charged and anionic membrane surfaces depositing likely charged polysaccharides on a cellulose membrane surface.
Specific nano particles were embedded into the polysaccharide coating to achieve:
- Antimicrobial activity (Ag, Cu, ZnO, Ag, Pt particles) ;
- Optical properties (TiO2, ZnO, silica nanoparticles);
- Flame retardency (layered silicates, clay nanocomposites);
- Catalytic devices.
In order to improve the understanding and enlarge the material basic for the demonstrators a variety of PS derivatives and stabilized nanoparticle were synthesized and combinations of both, the PS functionalities and nano ' particles was prepared. These combinations had all together the common ground of similar chemical and physical basic processes and technologies.
Together with the industrial partners the technologically promising combinations were defined at the project stage 'final selection of topics', focused on the 4 main targets (demonstrators), see Figure 3. Due to the fact that numerous approaches were possible, a very restrictive selection process was needed to focus on the defined targets. The selection criteria were defined in accordance with the industrial partners. Criteria were a combination of the propability to reach the technological goals (risk of technology failure and unexpected problems), market size, commercial benefits and estimated time to market as well as environmental aspects defined by LCA. The target was to bring these demonstrators towards a pilot scale production and application.
In addition, beside these technologically very demanding but realistically achievable targets we defined that additional visionary target(s) not in the industries primary focus but of demanding scientific and technological properties with future industrial applications might also be developed.
1.3.2 Project organization
The research and development activities were organized (Figure 4) in the following work packages:
- WP1: Chemical functionalisation of PS.
- WP2: Nano-paticle systems: Creation, dispersion, characterisation and interaction with dissolved polysaccharides.
- WP3: Interaction of functionalised PS with cellulose matrix and embedding of nano-particles into/onto PS coated cellulose matrices.
- WP4: Development of surface functionalisation of films and membranes.
- WP5: Development of surface functionalised fibres and non wovens.
- WP6: Life cycle assessment.
- WP7: Management.
- WP8: Dissemination.
1.3.3 S&T results
1.3.3.1 WP1: Chemical functionalization of PS
Objectives
1. Dissolution of cellulose and other polysaccharides in different solvents as well as characterisation of the solutions obtained.
2. Chemical and physical functionalization of cellulose and other polysaccharides.
3. Transfer into the pilot scale.
Tasks
1. Dissolution of cellulose and other polysaccharides in different solvents, solution characterization and properties. Goal was to prepare, to characterize and to understand cellulose-starch mixtures in ionic liquid in the fluid and solid state.
2. Synthesis of polysaccharide derivatives with different functional groups, degree of substitution and partially region-selective derivatisation.
3. Synthesis of cationically charged cellulose moieties and coating on polysaccharide to improving the binding properties of antibody-proteins on surfaces (e.g. glass).
4. Scale up of new functionalized cellulose moieties.
Significant results
- Cellulose and starch coexist without any phase separation in EMIMAc as far as total polymer concentration used is far from their dissolution limit. Cellulose- and cellulose/starch hybrid-films were prepared using ionic liquids as solvent. The starch was found to be inhomogeneously distributed in the hybrid-films. Their permeability dropped with pressure increase.
- Several new cellulose derivatives providing different functionalities were synthesized with degree of substitution and regio-selectivity.
- Cellulose-i?-lipoate sulphate was found to stabilize gold nanoparticles. Single hollow fiber modules provided by X-Flow have been coated with 6-deoxy-6-azido/aminopropargyl-carboxymethyl cellulose ' evaluation at X-Flow revealed significant loss of permeability.
- The binding of proteins on glass and polymer surfaces was improved using cationically charged cellulose moieties. After the successful antibody immobilization on the amino cellulose modified layer, these layers were used for a real-time CRP (antigen) detector system.
- Scaled up products of specific polysaccharide compounds are available.
1.3.3.2 WP2: Nano-paticle systems: Creation, dispersion, characterisation and interaction with dissolved polysaccharides
Objectives:
1. Synthesis of metal, metal oxide and semiconductor nanoparticles.
2. Adjustment of the nanoparticle chemical composition, size, shape and dispersity.
3. Optimisation of nanoparticle physical properties for individual demonstrators.
4. Preparation of stable nanoparticle dispersions in dissolved PS and derivatised PS.
5. Optimisation of nanoparticle porosity in terms of nanopores and pore size dispersity.
6. Study of dispersed nanoparticles interactions with cellulose and PS (modified/raw).
7. Development of robust models of real nanoparticle-polysaccharide interactions.
Tasks and participating partners
1. In-situ preparation of stable TiO2 (TiO2/SiO2) ' cellulose derivatives colloidal solutions and preparation procedure optimisation for in-situ deposition on cellulose surfaces (P5).
2. Synthesis of Ag-cellulose derivative nanocomposites for antimicrobial fibres (P1, P2).
3. Nobel nanoparticles for hormone removal (P5, P8, P9).
4. Preparation of aqueous nanoparticle suspensions in larger scale (P8).
5. Enhancement of understanding of the nanoparticles dispersion process in cellulose solutions and preparation of cellulose acetate nanoparticles (P1, P3).
Significant results
- The process to stabilise aqueous dispersions of TiO2, Ag and metal nanoparticles using water-soluble polysaccharides was optimised. Polysaccharides can be used as reducing agents as well as stabilisers at low temperatures in cost-effective, environmentally friendly reactions. These dispersions of porous nanoparticle/PS nanocomposites are stable at room temperature for many months and sometimes for more than one and a half years.
- New synthetic methods to prepare colourless Ag nanoparticles and in situ Ag nanoparticles using microwave irradiation were developed and used for Litija's demonstrators to produce fibres with significant antibacterial properties against resistant bacteria, such as MRSA, found in hospital environments, for example. The size and shape of the nanoparticles could be controlled from very small (app. 10 nm) to very large (app. 600 nm).
- Microporous Pentair X-Flow membrane WP4 demonstrators coated with PS-stabilised Ag nanoparticles from aqueous colloidal solutions showed significant antibacterial activity for water remediation.
- An environmentally friendly microwave synthesis of Ag nanoparticles in aqueous solution was developed, whereby the synthesis reaction time was reduced by factor of 60.
- A route to synthesize cellulose acetate nanoparticles with different surface functionalities was developed
- An environmentally friendly ZnO nanoparticle method of preparation in aqueous solvents was successfully up scaled. These platelets have been used for Litija's demonstrators to produce fibres with significant antibacterial properties.
- Reduction of the undesired TiO2 photocatalytic activity was achieved by coating the nanoparticle with APTES.
- Core/shell titania/silica nanoparticles were prepared and deposited using a layer-by-layer approach on Mondi's demonstrator paper that became whiter, brighter and more stable to degradation by sunlight.
- Preparation of carbon black sub-micro particles in aqueous cellulose solutions. Microporous membranes (X-Flow demonstrator) coated with Pd-stabilised Ag nanoparticles from aqueous colloidal solutions showed significant heterogeneous catalytic activity for continuous-flow reactions in water.
1.3.3.3 WP3: Interaction of functionalised PS with cellulose matrix and embedding of nano-particles into/onto PS coated cellulose matrices
Objectives
1. Preparation, characterization and activation of reference matrix materials (cellulose, films, fibres, membranes).
2. Adsorption-desorption of dissolved derivatised Cell and PS (modified and raw) on cellulose matrices.
3. Embedding/immobilisation of nano-particles on original and coated Cell surfaces.
4. Characterisation of Cell ' nano-particles compounds.
5. Modelling of the adsorption-desorption process.
6. Transfer into small scale pilot scale.
7. Scientific hot topic ' Microfluidic protein detection system.
Tasks
1. Study of adsorption of polysaccharide stabilised nanoparticles on cellulose model films and real surfaces.
2. Antifouling / antimicrobial coatings on membrane substrates.
3. Model coating development to improve barrier properties.
4. Scientific hot topic ' Microfluidic protein detection system.
5. Cellulose matrix pre-treatment and in situ formation of Ag nanoparticles.
6. Modelling of adsorption process in molecular and micrometer scale.
Significant results
- General know-how according the NP adsorption process, its dependence on ionic strength, pH and NP stabilisation agents.
- Coating formulation of inorganic oxide particles (i.e. TiO2), prepared in a solution of a polysaccharide (i.e. CMC), can serve as an efficient modifying agent, with which new properties and functionalities can be imparted to different cellulose matrices.
- It is the dispersing and stabilizing ability of a cellulose derivative solution that ensures the maximum effect provided from active particles ' insufficient stabilization would inhibit their activity. In addition to that, stable polysaccharide-based particles' dispersions act as a carrier and adsorbing driver for homogenous deposition of inorganic particulate matter on surface of various cellulose substrates.
- Activation of cellulose fibres for enhanced particle synthesis and formation of firmly-attached coatings.
- In situ preparation of Ag nanoparticles on fibre surfaces causes strong deposition withstanding several washing procedures.
- Molecular modelling of the cellulose surface, their interaction with water molecules and oligosaccharides using semi-empirical and ab initio methods.
1.3.3.4 WP4: Development of surface functionalisation of films and membranes
The demonstrator deliverables in WP4 are twofold and are partner specific. The deliverables for X-FLOW BV have been achieved and not only substantially surpassed are somewhat in advance of that expected at this point in time.
The deliverables for Innovia Films were finally also achieved. More effort was needed due to the need to produce model films with consistent properties that enables the transfer of the laboratory work achieved in WP2 and WP3. A pilot plant production of Cellophane films with increased hydrophobicity and decreased water vapour transmission was obtained.
Cellulose acetate hollow fibre membranes with antimicrobial coating and enzymatic hormone degradation
X-Flow hollow fibre standard membranes were coated with hydrophilic silver containing sol-gel material. The permeability of clean water was investigated with flow tests. The morphology and elemental composition of the coated membranes was investigated with scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDX).
The chemical stability of the coated membranes against sodium hypochlorite cleaning was investigated. In addition long term filtration experiments with surface water were performed. EDX and SEM measurements revealed a successful immobilisation of silver in the membrane structure (Figure 23). Long term filtration tests showed that low amounts of Ag have no negative effect on the life time of the membrane.
Up-scaling on fibre modules (RX300 modules) of the in situ coatings with silver was performed (Figure 24). Again SEM, EDX and flow tests were performed; the chemical resistance was investigated by a sodium hypochlorite treatment.
It could be shown that in situ coating with silver reduces the clean water permeability of fibre modules. Also the chemical stability is reduced when silver is present in the membrane. Nevertheless silver was successfully immobilised inside the membrane structure. Therefore the silver has a potential application as antimicrobial coating.
Cellulose acetate hollow fibre membranes were successfully coated with SiO2. EDX studies revealed the presence of silicon over the entire membrane structure. Flow tests with clean water showed a reduction of the permeability even though no changes in the pores size of the membrane could be observed.
Cellulose acetate hollow fibre membranes were successfully coated with SiO2. EDX studies revealed the presence of silicon over the entire membrane structure. Flow tests with clean water showed a reduction of the permeability even though no changes in the pores size of the membrane could be observed.
For the increase in hydrophilicity and improvement of anti-fouling properties, model surfaces of cellulose acetate and single hollow fibre membranes were coated with multi-layers of Chitosan and carboxymethyl cellulose. The controlled release of the multi-layers for a cleaning of membranes was investigated. Multi-layer growth and controlled release were evaluated by optical thickness; contact angle measurements atomic force microscopy and scanning electron microscopy.
The polysaccharide multi-layer built up could be controlled with the pH value of the coating solutions. In general, thicker layers are produced at lower pH values. Layers with a thickness of several hundred nanometres can be obtained. A successful removal of these coatings can be performed under defined washing conditions. This opens the way to generate anti-fouling coatings which can be regenerated.
Further investigations on the coating conditions of membranes are necessary. The long term anti-fouling properties of the membranes with surface water are under investigation. For testing the antimicrobial activity of surfaces, a combination of methods was developed. Electron microscopy, fluorescence microscopy and real time PCR were successfully combined to investigate bacterial growth on surfaces. Chitosan/CMC coatings on cellulose acetate surfaces turned out to be very efficient in inhibiting bacterial growth. These coatings are therefore used to create anti-fouling layers on cellulose acetate surfaces.
For the enzymatic digestion of endocrine compounds horse radish peroxidase enzymes were successfully isolated from pichia pastoris fermentation cultures. Purification was performed with anion exchange and size exclusion chromatography. Pure enzymes with high activities and the ability to digest estrogens were obtained. Those enzymes are covalently immobilized on layer coated CA membranes and are tested using medium sized pilot membrane modules.
Figure 25 shows the resistance of the membrane versus the filtration time of real surface water at the Twente canal in the area of Enschede. The surface water is still standing canal water, which has a high organic load. The high organic load mostly fouls the membrane dramatically and is therefore a good indication if a low fouling membrane is present or not.
The graph shows that our standard membrane (blue line) starts similar to the in-situ Ag coated membranes. This also indicates that the permeability (resistance) did not change after coating the Ag on the membrane. During filtration time, fouling is built up on top of the membrane and with that the resistance of the membrane increases. The standard membrane lies slightly higher than the coated membrane, which indicates that the coated membrane fouls slightly less than the standard membrane. This trend can also be seen after a first chemical backwash, where all the fouling material is removed from the membrane and the resistance is going back to zero. Also after all other chemical backwashes, the coated membrane stays below the resistance of the standard type of membrane.
The production of large cellulose acetate and cellulose acetate butyrate flow modules was performed (Figure 26). The influence of the wall thickness of the membranes on the formation on voids was studied and process optimisation led to void free fibres. Fibre bundles of 300 mm length were assembled to a final filtration unit in PVC housing tubes.
Performed pilot plant production and testing:
- Up-scaling of membranes and modules
A new type of more chemically stable cellulose acetate derivative (cellulose acetate butyrate) is used to produce new type of ecological friendly membranes for the surface functionalization of these membranes using embedded nano-particles. The problem by up-scaling this production process is the formation of perfect sponge like-macrovoid free structures. Thus it is now possible to produce for X-Flow membranes from renewable sources. Intermediate pilot plant modules are produced with a 300 mm long tubular housing. After spinning of sufficient amounts of hollow fibre membranes from cellulose tri-acetate (CTA) and cellulose acetate butyrate (CAB) under good circumstances to prevent macrovoid formation, production of the first large pilot module could be started
- Coating of layers and the influence on membrane properties
The enzyme or nanomaterial has to be coated on top of the membrane sub structure to get fixed on the membrane. Therefore a layer by layer coating technique was developed with X-Flow and the University of Graz.
The industrial coating procedure consists of five different steps (Activation of the membrane surface, Carbomethoxycellulose (CMC) coating, chitosan coating, 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide) (EDC) step, enzyme step). The influence of this coating on the membrane performance should be limited as much as possible to maintain the full filtration performance of the membrane. Parameters for this performance are mainly water permeability and mean flow pore size (MFP). The influence of the coating layer on these parameters
- Testing of new materials
- Low fouling membranes (Demonstrator 1)
- Immobilization of HRPO enzyme for hormone degradation (Demonstrator 2)
- Transfer into larger pilot scale and field test
- Recent field tests on low fouling behavior membranes (Demonstrator 1)
- Field tests on endocrine disrupter removal membranes (Demonstrator 2)
Improvement of barrier properties of Innovia regenerated cellulose films
Two different systems were applied in the pilot production trials:
- 100% pre-condensed water borne SolGel was a solution supplied by CHT and was place in the final Additive bath of the casting process before the heated cylinders. A new coating smoothing arrangement as well as coating return was designed to enable even lay down of the coating. Laboratory tests implied that the results should be in the order of 20g/m2/day for water vapour.
- Ionically stabilised polyelectrolyte bi-layer with exfoliated Montmorillonite from Graz University used the final three baths having a wash bath in between the two application baths. Unlike the laboratory experiments multiple dipping was undertaken in each bath, in part due to the residence time required for mono-layer coverage. To simulate the pilot plant conditions some lab experiments regarding dipping time and concentrations of the single components were performed. An overview of these experiments is shown in Figure 27.
The higher the concentration of the clay suspension the higher are the barrier properties, the reduced dipping time of 10 seconds gained even better barrier properties. These results represented the final proof that this coating system can be transferred to the pilot plant.
In order to condense the multiple coating steps of the LbL technique, another approach was used. Here the clay suspension and the polymer solution (polyvinyl alcohol) were blended prior the coating procedure. A threefold application of these coatings lead to similar results regarding the barrier properties like a 20 bilayer coating using the LbL approach. Here too, a drastic reduction of the dipping time (10s) did not lead to worse barrier properties.
Therefore both approaches were used to perform pilot plant trials.
The pilot plant itself (Figure 28), consist, like the production line, of a spinning bath, several bathes to functionalize and purify the film and of a dryer at the end of the line. The dryer consist of hot rollers (90 ?°C) which are heated by hot steam. The film is drawn through the line by rollers, which feature a certain surface structure to prevent creasing of the film. In the pilot plant usually films with a width of around 30 cm are used and the film runs with a speed of 5 m/sec through the line. Since we also applied multiple coating steps, the film was winded up after the dryer and run through the line again. So in total 3 pilot plant trials were performed: one with LBL technique (5 bilayers); one with condensed LbL technique (3 layers) and one with the CHT coating (1layer). From a technical point of view the transfer of the coating to pilot scale worked out fine. The results of the trials are shown in Table 3.
All coating approaches lead to very similar results concerning their barrier properties to water vapor. They are all in the range of 400 g/m2/day. Even though the goal of 30 g/m2/day was not achieved, the developed coatings have a lot of potential, since there is further room for improvements from the pilot production to large scale production. As stated before, the transfer of the coating systems from the lab scale to the pilot plant scale worked fine. Furthermore it has to be noted, that each of the applied coating systems uses water as solvent.
Significant results:
- The X-Flow demonstrator 1 (ant-fouling) is 100% completed. Up-scaling is done, new materials have been tested and further developed with the universities and the best results were transferred into pilot scale and field testing.
- Results from the field tests look promising, and the development for demonstrator 1 is close to the market introduction.
- Although the results on endocrine degradation look very promising (Demonstrator 2), the market introduction will need more detailed research to evaluate the potential of this promising technique.
- A patent application is under preparation together with the University of Graz.
- Work for the Innovia Films demonstrator 3 has shown promising results with barriers being achieved advanced to the barrier products produced by Innovia.
- The developed barrier coatings are biobased and applicable in aqueous systems.
1.3.3.5 WP5 - Development of surface functionalised fibres and non wovens
Litija's demonstrator
Fibre modification to achieve anti-bacterial (AB) properties
Standard modal fibres were selected for the surface modification according to innovative procedures developed in WP1, WP2 and WP3 of in-situ synthesis of nano silver particles immobilized on the fibre surface. The basis of this new procedure is optimized swelling of the fibre, which works as a reduction agent.
For the exhausting process for fibre finishing standard equipment was used to deposit the AgNP in and on the fibre. The in situ procedure does not require any additional thermal fixing procedure.
The developed procedure of the in situ Ag-particle synthesis gains antimicrobial fibres ensuring the presence of active Ag particles in the interior and exterior of the fibrous substrates. The surplus Ag particles that are formed in the treatment bath are stabilized by dissolved surface-located amorphous fibre fractions. Left-over treatment solution is therefore not regarded as a waste product to be discarded, but can be used as useful side-product.
Two types of yarn were produced in different blends:
- 100% CMD Modal AB (C-2011)
- 50% CMD Modal std / 50% CMD Modal AB (ML-2031)
During the spinning process an even distribution of the AgNP was achieved, the concentration depends on the yarn type. The quality parameters of the yarns show, that the modified modal fibres have completely adequate processing properties for spinning, which also results in sufficient physical parameters of the yarns with no regard to whether used in 100% or as blend with other fibres. Additionally, the yarn was twisted to determine if the AB modified modal fibres are suitable for blending with other chemical fibres from synthetic polymers. The results are positive.
Finally the fibres were knitted and T-shirts were produced. The results on the final product confirm that the 25% share of AB modified modal fibre assures sufficient antibacterial activity. The practical utility of the final products in domestic maintenance was also test with produced T-shirts. The final product did not show any negative aspects compared with the standard material.
Mondi's demonstrators
- Successful production of high-quality lab demonstrators containing 50 % chemo-thermo mechanical pulp CTMP and a slight mineral coating.
- Efficient colour shielding of commercially produced dyed paper upon exposure to UV light with application of polysaccharide based coatings (lignin) and implementation of lignin-calcium carbonate complex-powder into a starch slurry.
After exposure of reference and coated paper samples to sun (5 days), we see a clearly the effect of UV radiation on not protected samples. Colour appearance and lightness increased significantly with simultaneous pronounced decrease in chroma (Figure 30).
The Mondi demonstrator was not produced on large scale due to no clear competitive cost advantage due to actual pulp prices (shortage of CTMP).
Significant results
- In-situ modified modal fibre: for the efficient antibacterial activity (which is set at higher than 98% reduction of bacteria on textile, which undergone 10 washing cycles) the minimal share of AB modified modal fibres is 25%.
- The AB modified fibres can be blended with all natural and synthetic staple fibres.
- The process was implemented under industrial conditions (100 kg of AB modified modal fibres or more than 200 T-shirts).
- Successful production of high-quality lab demonstrators containing 50 % CTMP and a slight mineral coating.
- Efficient colour shielding of commercially produced dyed paper upon exposure to UV light with application of polysaccharide based coatings (lignin) and implementation of lignin-calcium carbonate complex-powder into a starch slurry.
- Patent application ('Antimicrobial Cellulose Material and Process of its Production').
1.3.3.6 WP6: Life cycle assessment
Objectives
1. To conduct Life cycle assessment (LCA) of P13 (Mondi) demonstrator, high yield pulp printing and writing paper, and P9 (X-Flow BV) demonstrator, hormone removal membrane. This is conducted by analyzing all synthesis routes of the NP of P13 (Mondi) and P9 (X-Flow BV).
2. To conduct an assessment of waste management of Surfuncell demonstrators (P9, P11 and P13) and report the findings in the form of a deliverable report.
Tasks
1. Collection of life cycle data of existing conventional product processes of P13 and P9.
2. Collection of data of all planned synthesis routes of P13 and P9 demonstrators from research partners.
3. Screening study of all planned synthesis routes of P13 and P9 demonstrators.
4. Detailed analysis of final synthesis routes of P13 and P9 demonstrators already chosen for up-scaling.
5. Collection of scale up data for analysis.
6. Collection of life cycle data of existing conventional processes P11.
7. Collection of data of all new synthesis routes of P9 and P11 demonstrators from research partners.
8. Screening study of all new synthesis routes of P9 and P11 demonstrators.
9. Detailed analysis of final synthesis routes of P9 and P11 demonstrators already chosen for up-scaling.
Waste management report
A waste management report was established to help the producers to devise better product life cycles and end of life strategies by integrating life cycle waste management aspects during product design and development stage. This report can also help producers to avoid business risks from potential EU legislations due to awareness and, consequently, better prepares these companies to create competitive advantage in the market place with early mover advantage. It is presented in the extended project documents.
Hormone removal membrane demonstrator by X-flow
Figure 35 shows that NREU (non-renewable energy use) of membrane and wood based GAC process are comparable but GHG emissions of membrane processes are lower than GAC. These are also membrane system's design boundaries to be fulfilled in order to ensure lower environmental impacts than GAC processes operating anywhere in the world.
Cost analysis of Surfuncell demonstrators
In the absence of commercial scale production and for confidentiality reasons, cost indices are presented here. These cost indices were estimated by our industrial partners. In two cases the cost of Surfuncell demonstrator is somewhat higher than the reference. However, as pointed out by one partner, Surfuncell products offer new functionalities, hence justifying the cost increase.
Significant results
- Improve resource efficiency: The resource efficiency of silver during T-shirt manufacturing is 60% which can be greatly improved by increasing the fastness of Ag NP on fiber surface.
- The process waste generated during different processes should be reduced and especially downstream processes should be given more priority.
- Limit the concentration of NP in the product: define the exact concentration required to meet the intended functionality during the product's useful life time.
- Design products that emit large particles or aggregates which will be easy to filter and reuse: Every NP is functionalized to meet its function.
- For silver NP containing products, it is important that excessive or unwanted silver ion release should be avoided throughout product life cycles since silver ions pose a 10,000-fold higher risk than silver NPs.
- Clearly label the products with NP characterization.
- Design products with end of life in mind: In order to avoid regulatory risks related to future REACH legislation or end of life legislations such as WEEE, it is recommended to Surfuncell companies to carefully consider the end of life (disposal, recovery/recycling) of their products before market entry of the products.
- Opportunity to invent new products to avoid waste management problems: The challenges posed by NPs during different product life cycles stages provide various business opportunities. Methods could be developed to recover aggregated NPs from activated sludge of WWTP.
Potential Impact:
1.4 Potential impact and main dissemination activities and exploitation of results
The socio-economic impact and the wider societal implications of the project Surfuncell are mainly reflected by the commercial demonstrators, which are clearly the most important outputs of the Surfuncell programme. These demonstrators should have a very real socio-economic and societal impact in many areas of the world as they will be brought to market and commercialised on a major scale.
Due to the fact that biobased materials are transferred into high value products impacts in terms of energy and non-renewable resources reduction can be clearly foreseen. The biobased materials are available in almost all regions. The developed high value products are partially connected with high tech instrumentation or large scale production devices but a good part can be produced with standard equipment. Both offers the possibility that these products will create or maintain jobs in even less developed regions. The research and development resulted also in high tech and high value products which will have some impact to the job situation in Europe.
1.4.1 Direct project related impacts
1.4.1.1 Basic research
The science in the field macromolecular chemistry, organic chemistry, nano-particle synthesis, material science, biotechnology was clearly promoted by the cooperation in this interdisciplinary project. New insight was created in these fields leading to a deeper understanding of basic processes in terms of functionalization of polysaccharides, the synthesis, formation and stabilization of nano-particles, the interaction at the liquid solid interface and of molecular aspects of the adsorption process and the involved driving forces.
The know-how development went far ahead of the focused direct application. Basic know how for further development project was gained mainly applicable for high value products.
Outcome
- Papers in peer-reviewed journals: 20 published, 1 in press, 4 under review, 5 in preparation.
- Lectures / posters at conferences: 80.
- Thesis/ Diploma: 13 finished, 5 under preparation.
1.4.1.2 Applied research
Multidisciplinary projects also integrating companies contribute always to the enlargement of all persons involved. The academic partner gain insight and understanding of the problems and limits in production process, the industrial partner develop a deeper understanding of the physical and chemical process background fostering further developments.
The intensive cooperation allowed the process development to be very focused on the industrial partners demand. Combined with life cycle assessments of the standard products and comparison with the new development decisions were made about development routs. The well defined R&D activities with clear targets and time lines necessary in such cooperation enforce a well organized work style from all partners. This is a great opportunity especially for young researcher to become used to the demands of an international development proposal.
Outcome
Workshops/trainings: 5 trainings were held during the project life-time.
1.4.1.3 Pilot plant production of demonstrators
The development reached the target of pilot products for all planed applications. Different levels of technology transfer were reached.
The industrial partner Litija, producing yarns achieved a product and a process almost transferable to large scale production.
The industrial partner Innovia, producing packaging material, achieved a new coating device able to replace synthetic polymer coatings connected with heavy chemical processes. The innovative product was already produced at pilot plant scale and shows interesting property improvements. Further improvements will extend the application range.
Drinking water purification membranes were developed together with the industrial partner X-flow. The company itself developed new membrane materials, the research partner processes to avoid biofouling and to degrade enzymatically hormone and hormone degradation products in drinking water. Pilot scaled devices were produced and are under test.
The paper producer Mondi could also develop in this cooperation a new paper coating with the possibility to create office paper with reduced demand on basic material, process chemicals and energy. This product was developed to a large laboratory scale and shows all demanded properties.
Beside the targets (demonstrators) defined at the project start several technologically 'Hot topics' were recognized.
Outcome
Products almost ready for production: 2 demonstrators (i.e. antimicrobial fibres and cellulose acetate hollow fibre membranes) are already produced in several 100 kg scale and transferred to potentially final products (new membranes, mixed yarns and T-shirts).
Products in pilot scale trial: 3 demonstrators are in this stage. The antimicrobial coating and the hormone degrading enzyme layer for water purification membranes, and the high barrier cellulose based packaging material.
Product in small scale trial: Paper sheet were already produced from high-quality chemo-thermo mechanical pulp. The demanded UV shielding and paper strength was demonstrated.
1.4.1.4 Industrial partners
The Surfuncell programme has provided financial stability and sustainability to NanoMePS, which is now on a sound financial footing and has employed a further chemist to boost its research and manufacturing capability. The Surfuncell programme has expanded the product portfolio of NanoMePS and provided it with know-how and expertise in the water-based synthesis of stable solutions of nanoparticles rather than using VOC based manufacturing of nanoparticle powders, which are much more difficult to process and which are much more of a concern from a health perspective.
1.4.1.5 Individual work packages
WP1, WP2, WP3 and also WP6 are essential pre-cursor steps to and facilitator of the later work packages 4 and 5 without which the demonstrators could not be realized.
Work package 1
The research work in WP1 was directed towards the use of polysaccharides from the pool of renewable resources to design highly engineered chemical compounds based on polysaccharides. Moreover, environmentally friendly solvents, in particular ionic liquids were applied as solvent for shaping and functionalization of the biopolymers. The polysaccharide-based products may impact the material properties at a low amount, i.e. as thin films. e.g. and thus they are used in the context of nano- and microtechnology.
Work package 2
The development of a portfolio of simple and scalable 'green synthetic methods' to produce stable colloidal dispersions of cellulose-stabilised organic, metallic and semiconductor nanoparticles using water as the solvent and cheap, available reducing agents, sometimes the cellulose derivatives used to stabilise the nanoparticles in solution, and cellulose derivatives as the capping and stabilising agents is of clear economic and societal relevance and commercial importance. The development of generally applicable environmentally friendly methods to prepare stable aqueous dispersions of a very wide range of metallic and semiconductor nanoparticles, which can be used in a very simple way to coat the outer surface of cellulose fibres, membranes, filters, etc, to produce a whole series of products based on renewable resources is of general importance to the development of nanotechnology and its uptake as a major manufacturing process. These methods should improve the efficacy and efficiency of the nanoparticles by their being concentrated on the surface in a thin film of cellulose-stabilised nanoparticles of the cellulose-based supports, while at the same time significantly reducing the amounts of nanoparticles required to achieve a given effect.
Work package 3
Integrating the basic materials and know-how provided by WP1 and WP2 towards compounds in laboratory scale. The portfolio of new polysaccharide derivatives providing a variety of functionalities, new cellulose dissolution processes and a large number of stabilized nanoparticles were the basement for the successful development of a variety of surface modification processes and coatings. Based on LCA data environmentally friendly process routs were developed for these surface modification / surface compounding processes. Processes as well as coating formulations are applicable in a far wider area as approached during this research program. The modelling processes performed provided deeper insight into the structural and energetic processes on molecular level.
Work package 4 and 5
The impact of these work packages is self-evident. Several demonstrator products were produced in pilot scale or pre-pilot scale proving the correctness of the basic strategy, of the developed new materials and process routs.
Work package 6
The life cycle assessment performed during the project on classical and new materials gave important advice for the definition of proper process routs with a low environmental footprint.
1.4.1.6 Commercial and societal impact
The commercial and societal benefits of this new approach are self-evident. The ability to tailor the size, shape and polydispersity of the nanoparticles, for example large nanoparticles with a diameter above 100 nm, and the ability to firmly fix these to the surface of naturally occurring and renewable cellulose derivatives using a new developed tool box of functional polysaccharide derivatives offers numerous applications and a wide field for new business opportunities far beyond the frame of Surfuncell.
The gained know how will also clearly provide tools to control and limit the toxicity, take up and proliferation of these nanoparticles in the environment and provide very significant the overall life-cycle benefits. Such considerations are important limiting factors in the general uptake of nanotechnology as a mainstream area of manufacturing.
The importance of all work packages is reflected in the economic and societal relevance and commercial importance of the demonstrators emanating from WP4 and WP5.
1.4.1.7 Gender aspects
Research, development and organization work was carried out from both female and male persons employed at industrial partners, researcher, PhD students and students.
1.4.2 Not directly project related impacts
1.4.2.1 Creation of research and technology transfer network
The essential task creating a European research area is the formation of networks performing multidisciplinary research and providing the transfer of research results into innovation. These networks are speeding up this very crucial transfer steps and provide so technological leader ship and new business, partially performed by SME founded by persons out of the research community.
1.4.2.2 Education of young scientists involved into the project
The exchange provided during the project with the industrial partners and other research groups is an essential extension of young persons education and reparation for the demands of their future jobs.
1.4.2.3 Education cooperation
Beside exchange also fruitful education cooperation was fostered. This included mutual lectures, lessons, courses with contribution of experienced lecturer and also the young persons involved including the definition and development of new research projects. Integrated into this cooperation was the network of excellence EPNOE, the Marie Curie project STREAM and the European master program TONI.
1.4.2.4 Exchange of R&D persons
The exchange of R&D persons between research groups an especially between research groups and industrial partner enlarged their degree of understanding and their possibility to understand the other sides needs and limits. This is an important experience and prerequisite for further technology transfer projects.
1.4.2.5 Impact on hosting universities and research organisations
The Surfuncell project has allowed the universities to expand their interests and expertise in synthesis, purification and characterisation of high-value added, functional polysaccharide derivatives, nanoparticels and organic/inorganic hybrid composite materials. Base on this they have excellent chances to further develop new materials in the frame of national and international projects. The project groups will continue to work on Surfuncell related research projects. The financial support allowed the purchasing of new research equipment partially financed by project money. The programme had als an impact on teaching because of the teachers' exposure to applied and industrial problems. The gained experience will be integrated into their teaching topics.
1.4.2.6 Centre of excellent PS research & technology transfer
All person involved build a temporary centre of excellence in this R&D area. In this case this will be prolonged and integrated into the European Polysaccharide Network of Excellence (EPNOE). The gained know how and networking will be further utilized in this frame.
1.4.2.7 Recognition in scientific and industrial world
The successful performance in such an international research project provides to all partner a positive recognition in the scientific as well as in the industrial community. Especially young person successfully active in such a network are able to use this for further promotion of their career.
1.4.3 The socio-economic impact and the wider societal implications
- High value products were developed and brought toward a pilot scale production. The future entering into the market will have positive impact on the employment situation of the companies.
- The early market penetration by the companies is fostered by the dissemination activities performed during the project.
- Improvement of life quality: The product developed by X-flow, Innovia and Litija will have direct influence the quality of life of many persons. The water purification membranes reducing the hormone pollution of drinking water, the biobased packaging material because of its absolute non toxicity and the antimicrobial finished textiles in aspects of person hygiene and hygiene in public areas.
- Improvement of environmental conditions: The biobased high-value materials will be produced following process routs which were selected via LCA in order to provide less deposition of synthetics materials, less consummation basic materials, energy and land.
1.4.4 Main dissemination activities and exploitation of results
The research carried out in Surfuncell generated considerable output which was put forward to industry groups. As already foreseen at the start of the project, industrial partners will produce new equipment and as such exploit the project's results.
Part of the research and development work performed in Surfuncell was incorporated directly in prototypes for future commercial production. Despite the fact that in some cases additional development and validation work will still have to be done, some of the new technologies and products may already be implemented by the industrial partners within the near future after the termination of the project.
Finally, it is foreseen that universities and research institutes will exploit the results by integrating them into their educational and training programmes, allowing more and better qualified engineers completing their master and PhD programmes. The Surfuncell project members University of Graz, University of Maribor, ARMINES, University of Jena, University of Hull and University of Utrecht are such an example which makes use of results in their master and PhD programmes.
As documented above, the focus of Surfuncell was predominantly on research, development, validation, verification, and implementation of technology and products which can be produced and deployed at a European and global level. The technologies and concepts developed were published rather than patented. Consequently, there is one patent application at the moment, and the other one is under preparation. There are, however, quite some several examples of concretely exploitable foreground, the most relevant ones being listed in table below.
List of Websites:
Project Coordinator:
Prof. Dr. Volker Ribitsch
University of Graz
Institute of Chemistry
Heinrichstrassse 28
A ' 8010 Graz
Austria
Telephone:
0043 316 380 5418
E-mail address:
volker.ribitsch@uni-graz.at
Website address:
http://www.surfuncell.eu