Recycling of APC-2 offcuts

Abstract

A method for reclaiming waste APC-2 offcuts from pattern cutting of prepregs is reported. The method entails cutting the scrap prepreg into small flakes and compounding them with additional poly(ether ether ketone) (PEEK) resin in a twin-screw extruder to produce a short fibre-reinforced injection moulding grade material. The tensile and flexural properties of mouldings made from the reclaimed material were measured and compared with those of mouldings made from a commercially available injection moulding grade short carbon fibre/PEEK. The molecular weight, degree of crystallinity and fibre length distribution of the various samples of PEEK and carbon fibre/PEEK at different stages of processing are reported. Specimens made of the recycled material were stiffer and stronger in tensile loading than the ones made from the commercial moulding compound. This was due to the presence of fibres with a longer average length and better interfacial adhesion between the fibres and matrix in the recycled material. The PEEK matrix in the recycled material had a higher crystallinity than that in the commercial material. A simple economic assessment has been performed showing that, in principle, the recycling route is viable.