Fastening Points

Sustainability for composite materials

07 Dec 2023

Composite materials are playing a significant role in the continued push for lightweight design and in the drive to meet net-zero targets. Sustainability for composite material production, processing and waste management is now an urgent area of research and development.

This was evident at Advanced Engineering 2023, where much of the exhibition space was dedicated to showcasing composite materials and innovations in processing techniques.  The event served as a platform for the UK composites industry and representatives from the automotive, aerospace, and marine sectors to converge, share insights, and discuss latest developments, challenges, and future requirements.

These are our key takeaways from the event.

Processing of composite materials needs to be more sustainable

Poster for net zero 2050

The shift to alternative vehicle powertrains and the ongoing pursuit of lightweight structures has significantly reduced carbon emissions associated with day-to-day vehicle usage. However, recent life cycle assessments reveal a new challenge: as emissions associated with vehicle usage continue to decrease, those associated with material production and processing become the primary contributors to a vehicles overall carbon footprint. To reach net-zero targets set by many automotive OEMs, there’s a pressing need to reduce the carbon emissions associated with the materials and processing methods used for vehicle production. This emphasizes the need to reduce the carbon footprint of composite materials and processing. Sustainability for composite materials is a pressing requirement.

One approach for reducing the carbon footprint of composite prepreg is eliminating the requirement for frozen storage, hence reducing the associated energy requirement. SHD Composites showcased this approach by introducing a new prepreg series that can be stored and transported at 5°C instead of -18°C (with a shelf-life of 1 year). Additionally, this range of prepreg can be snap cured in 5 minutes at 160°C, reducing the energy consumption associated with material processing.

Natural fibre composites are finding applications, but further development is required for widespread adoption

Sustainability for composite materials through natural fibres

Natural fibre composites are a continued focus, with many recent exhibitions showcasing these materials. However, reports indicate that the mechanical properties of natural fibre composites can be inconsistent and challenging to predict. This uncertainty has resulted in some hesitation, particularly in the automotive industry, to fully embrace these materials. While there are instances of using natural fibre composites for specific vehicle interior components, such as seat liners or interior door panels, further work and development is needed for widespread adoption.

Composite waste needs to be seen as a valuable resource

Reclaiming fibre reinforcement from end-of-life components or manufacturing waste remains a significant focus. Various recycling strategies have been developed and are well documented, yet questions persist on the optimal use of reclaimed fibres. Since reclaimed fibres are typically discontinuous due to shredding prior to recycling, one potential method involves using these reclaimed fibres in place of chopped virgin fibres for discontinuous composite materials, such as sheet moulding compound (SMC). However, this depends on establishing a reliable and robust supply of reclaimed fibre reinforcement.

PRF Composite Materials presented an alternative approach to using recycled/ reclaimed fibre reinforcement. They adopt a fibre alignment strategy to produce an aligned, discontinuous fibre prepreg with 90% retention of mechanical properties compared to a virgin unidirectional prepreg.

The challenge ahead

The advantages associated with composite materials are now well understood, and composite materials have huge potential for a vast array of applications. The challenge now lies in making composite material manufacturing, transportation, storage, processing, and disposal more sustainable. This involves using less energy, reducing waste, and introducing circular practices throughout the materials’ lifecycle.