Manufacturing of thermoformable hybrid carbon fiber laminates

The manufacturing of carbon fiber (CF) laminates with hybrid thermoset/thermoplastic matrix has been investigated following different routes. Hybridization has been carried out during lamination, by alternating epoxy matrix prepreg plies and polyamide (PA6) films. Compression molding has been performed for laminate agglomeration. Epoxy-matrix carbon-fiber prepregs have been cured before compression molding of the hybrid laminate (namely “pre-cured”) or simultaneously (namely “co-cured”). Pre-cured plies have been processed by hot pressing or in open air, i.e. in oven without applying any pressure. Pre-cured plies in oven showed a higher level of adhesion in the final hybrid composite. Neat laminates have been manufactured for comparison and both thermal and mechanical characterization have been carried out on hybrid and virgin composites. High mechanical performances have been achieved by the hybrid matrix composites with the one obtained by co-cured prepregs having a bending strength of about 430 MPa. Composites multi-functionality has been explored in terms of thermoformability; the hybrid laminates have been manufactured in flat configuration and have been thermoformed into a U-shape with a bending angle of 90°. This aspect represents an additional property of hybrid laminates since thermoset CF composites cannot change their shape after curing.