Recovery of carbon fibers from cured and uncured carbon fiber reinforced composites wastes and their use as feedstock for a new composite production

Abstract

Cured and uncured scraps from manufacturing of epoxy based carbon fiber reinforced composites were treated with a pyrolytic process to provide, as solid residue, carbon fibers to be re‐used in new composites production. The industrial scraps were pyrolyzed at different temperatures in a 70 kg batch pilot plant and the pyrolysis products (gas, oil, and solid) were fully characterized. The solid residue (carbon fibers covered by a carbonaceous layer) was subjected to a further oxidative step at 500 and 600°C for different residence times to provide fibers devoid of any organic residue that did not volatilize during pyrolysis. The effects of both pyrolysis and oxidative process on the recovered fibers were evaluated by scanning electron microscopy and Raman Spectroscopy. The reinforcement behavior of pyrolyzed and pyrolyzed/oxidized chopped fibers, compared to virgin fibers, was tested in the production of new Chopped Carbon Fiber Reinforced Composites. The optimized double pyrolysis/oxidation process was found to provide fibers whose performance in the composites were comparable to the virgin ones. POLYM. COMPOS., 36:1084–1095, 2015. © 2015 Society of Plastics Engineers