Prodrive Composites has been a leader in the development of sustainable composites, through its own technology P2T (primary to tertiary), which reuses carbon fibre multiple times.  Here John McQuilliam FIMM, director of engineering at Prodrive Composites and board member of the British Composites Society, looks at how natural fibres can be used to replace carbon.

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“We have parallel developments using two approaches to sustainability, based on recycled fibres and natural fibres. Though our conventional composite manufacturing will continue, we expect the major growth in the business to be from recycled products, including the recycling of our own products to make new parts.

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NATURAL FIBRES

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Natural fibres such as flax are not just carbon neutral, they can be carbon negative because they capture carbon as the plant grows and lock it into the finished part. The largest sustainable composite component we’ve designed and manufactured was the rear wing for the Aston Martin Vantage GT4 race cars. The regulations for this category require any non-standard aerodynamic surfaces to be manufactured using completely natural fibres and natural cores, so it was an ideal application for us.

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Though flax-based composites do not match the mechanical strength of carbon composites, they inherently provide superior vibration damping so we carried out extensive engineering analysis to ensure we met all the requirements. These included strict aerodynamic, weight and deflection targets as well as cost and manufacturing volume constraints. We developed an optimum combination of weaves, laminates and manufacturing processes to minimise labour requirements and material costs.

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With Formula 1 recently announcing its plan to become carbon neutral by 2030, we expect to see considerable growth in demand from across the motorsport sector for sustainable natural composites in future.

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We are making our whole business more sustainable through measures such as: improved process energy efficiency from shorter cycle times and lower temps; replacing wooden pallets with cardboard ones which are easier to recycle and lighter to transport; and exploring the switch to re-usable films and vacuum bags. We are also upgrading our PLM/engineering control system to a paperless configuration; we are already paperless in our external supply chain controls and will add our internal processes to the system.

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BIO RESINS

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Besides recyclable composites and natural fibres, we are also looking at the resins used. Bio-resins made from plant-based stock sacrifice some of the ultimate composite performance but offer a big advantage in sustainability. As a commercial company, we generally need a customer enquiry to justify onward development. There is a ‘sweet spot’ for manufacturing volume, not one-offs or thousands-off but made in quantities of a dozen to a few hundred; this is typical of niche automotive applications and is always our immediate target when we are developing a new process.”