Graphene-reinforced polymers ready for commercialisation
To this day, graphene remains expensive enough to discourage its large-scale incorporation into commercial products. But this hasn’t been preventing researchers across Europe from moving forward with the development of materials and production techniques that can pique industry interest as larger batches of graphene become available at a lower cost. The POLYGRAPH (Up-Scaled Production of Graphene Reinforced Thermosetting Polymers for Composite, Coating and Adhesive Applications) project is one of these pioneering ventures. By bringing together 14 partners, including small and medium-sized enterprises (SMEs), companies, universities and a research centre, the project aimed to deliver industrial-scale quantities of graphene-reinforced thermosetting polymers. “We tried to look at different ways to improve the thermomechanical and electrical properties of coatings, additives and composites,” explains Maria Konstantakopoulou, Development Engineer at project coordinating company Coventive Composites. Once the target performances were defined, the team picked suitable polymers, outlined a range of graphite and graphene grades, and identified suitable exfoliation and dispersion techniques that would eventually allow them to scale up production whilst ensuring that graphene remained well-distributed in the final product. As Ben Hargreaves, coordinator of POLYGRAPH, explains, the idea was to produce “on a scale that would be viable for other companies, enabling them to consider integrating our solution in their current or future products”. Large-scale conversion of composite materials indeed remains an obstacle to market adoption. Once project partners became able to produce as much as 100 kg of graphite and 25 kg of graphene per batch, new horizons opened up. Many different composite materials were produced by the project consortium, and were then evaluated for their electrical conductivity and mechanical properties. The most promising coatings, adhesives and composites were used in demonstrator parts, respectively an aerospace structural element, a coated aerospace radome/fairing element, and a rear seat back panel for automotives. Benefits include better structural behaviour, weight reduction, aesthetics, electrical properties and fire retardation. “One of the main advantages of the graphene-reinforced composites resulting from this research and development process lies in their electrical properties, making them suitable for electromagnetic (EMI) shielding or for the de-icing of wind turbines,” Konstantakopoulou points out. Waiting for the right opportunity Gary Foster, who acted as project manager on POLYGRAPH, explains that commercial perspectives vary strongly for each of the three materials. “On the coating side, project partner HMG Paints can pretty much go straight to production because what we developed is not too far away from the products that they currently sell. Adhesives, on the other hand, are a bit more price-sensitive. It doesn’t mean our partners won’t be using those materials, but they just wait for the right moment in time where people will want that product.” The third product, a pre-impregnated composite fibre or pre-preg, was particularly important for Coventive Composites, as Hargreaves highlights: “Pre-preg development wasn’t originally programmed into the project as heavily as what we ultimately ended up doing. We also looked at other production techniques like infusion, but early work made it clear that pre-preg was going to be the optimum technique.” Both he and Foster agree that the company should now focus on finding the right niche market for this composite, and that future efforts should focus on finding out what potential customers need and how the product can be refined to meet their expectations. Until then, the team will be looking at the evolution of graphene. “There is a need for a certain level of generalisation,” Foster explains. “For example, if we want to use our product in the aerospace sector, customers will need certain fundamental data from graphene producers that currently they are not able to provide. These are obstacles that we cannot overcome on our end.” With this in mind, the POLYGRAPH consortium has been working closely with the Graphene Flagship, creating a link between academics and industry so that the former’s research better matches the needs of the latter. Eventually, this would allow Coventive Composites to bring to market innovative solutions for the likes of EMI shields or the de-icing of wind turbine blades.
Keywords
POLYGRAPH, graphene, coatings, adhesives, pre-preg, composites, thermosetting polymers
