From aerospace to the automotive sector, Carbon Fibre Reinforced Polymer (CFRP) is a highly valuable engineering material used across industry. CFRP offers greater strength and energy absorption at a fraction of the density of steel equivalents.

While the use of CFRP provides more sustainable transportation solutions and reduced carbon emissions through vehicle and aircraft light-weighting, Carbon Fibre (CF) production and end-of-life disposal can have a far greater environmental impact than any metal; with up to 40% of CFRP going to landfill.

To look at how the environmental impact of CFRP could be reduced, researchers at WMG led by Professor Kerry Kirwan worked closely with industrial collaborators to create recycled CF composites with comparable valuable properties of virgin CF composites but, with significantly reduced environmental impact.

Reducing the environmental impact

Recycling carbon fibre (rCF) offers three distinct advantages over using new (‘virgin’) carbon fibre: lower cost (approximately 40% cheaper); security of supply (mitigating shortages of virgin fibre); and improved environmental sustainability (reducing waste bound for landfill and boosting re-use levels). However, rCFs are not a straightforward substitution for virgin fibres and converting them into a useable product is a lengthy and technically complex process.

To create a recycled CF system for use in high-performance manufacturing industries, including automotive and aerospace, the team at WMG undertook extensive fabrication and analysis of materials and production methods. Testing included fibre material, length and arrangement; timing and temperature of the matrix agent; optimising moulding processes and assessing the associated environmental footprints. This produced a comparison of properties for different types of carbon fibre, which allowed for a full assessment of cost against quality.

The team worked closely with engineering designers in industry to ensure the materials were sufficiently robust and could be successfully utilised within the product development process. A collaboration with local employer and industrial partner Gen 2 Carbon (formerly ELG Carbon Fibre Ltd), one of the largest carbon fibre recycling plants in the world, led to development of the innovative lightweight G-Tex TM– a thermoplastic rCF product range of materials, achieving £2,000,000 sales annually and now in use by companies across 26 countries.

Research at WMG has enabled mass production of G-Tex TM which has driven the innate environmental benefits of using recycled materials. Gen 2 Carbon’s 1,700t capacity plant has a concomitant saving of 52,700tCO₂eq in global warming potential vs. virgin carbon fibre production each year which is the equivalent to the greenhouse gas emissions from 11,385 passenger vehicles driven for a year, or the carbon sequestered from 68,824 acres of forest.

Professor Kerry Kirwan, WMG commented: “Our research and collaboration with Gen 2 Carbon is a prime example of an important industrial-facing research which is solving specific production challenges and driving circular economic innovation.

Not only is our research contributing to a more sustainable future and helping to significantly lower costs to use recycled carbon, but it’s also benefiting the economy too. Improved production is helping to increase the growth of our industrial partners sales and it’s further supporting the local economy by protecting and creating jobs in the Midlands region.”

Frazer Barnes, Chairman and CTO of Gen 2 Carbon, concluded: “The research undertaken by Professor Kerry Kirwan and his team has enabled Gen 2 Carbon to become pioneers of sustainable CFRP recycling; without this research we would not have been able to achieve this success.

Growth and inward investment on such a rapid timescale between 2016 and 2020 would have been impossible without input from the University of Warwick, accelerating Gen 2 Carbon to world-leader status for carbon fibre recycling far sooner than would have occurred without this greatly valued collaboration”

For more information about this research visit: https://warwick.ac.uk/fac/sci/wmg/research/materials/smam