Increasing carbon fibre use in cars

In addition to being lightweight for fuel efficiency, high-performance composite materials for the transport sector should have the potential to be used in fast production processes. Currently, production volumes tend to be limited to a few hundred or a few thousand units per year for aerospace or sports car applications.

The project HIVOCOMP (Advanced materials enabling high-volume road transport applications of lightweight structural composite parts) changed that by developing two new high-volume materials for carbon fibre-reinforced plastic (CFRP) parts for cars and suitcases.

The first developed system was advanced polyurethane (PU) thermoset matrix materials that showed improved mechanical performance and reduced cycle times when compared with the most often used epoxy matrix. Replacing this conventional matrix system with PU also enabled combining fast curing with high toughness and a high glass transition temperature. Addition of nanoparticles in PU allowed further improvements in processing – reduced resin viscosity and reaction kinetics – as well as in thermal and electrical properties.

Consortium partners built demonstrators using this new material in structural parts of a car. These included the inner bonnet, rear seat back panel, and the B-pillar between the front door and the back door.

Another HIVOCOMP breakthrough was to hybridise self-reinforced composites (SRCs) – polypropylene (PP) and polyamide – with carbon fibres. HIVOCOMP followed several strategies to develop two SRC versions. In the first case, a small amount of carbon fibres allowed SRC stiffness to increase without reducing toughness. In the second case, larger amounts resulted in increased toughness, with stiffness remaining high. Reduced production times were achieved through the thermoforming process.

Project partners successfully produced a hybrid SRC suitcase that was found to be 10 % lighter than current PP suitcases.

The advanced materials produced in HIVOCOMP result in short cycle times, showing unique promise for cost-effective, higher-volume production of high-performance CFRP parts.