Recycling of wet carbon fiber-reinforced plastic laminates by thermal decomposition coupled with electrical treatment

Abstract

The use of carbon fiber-reinforced plastics (CFRPs) produces moisture-absorbing CFRP waste, which is usually recycled via thermal decomposition treatment (TDT). However, the oxygen gas generated during heating can hardly penetrate dense CFRPs, resulting in nonuniform damage to the recovered carbon fibers (rCFs) collected from the outer (oCFs) and inner (iCFs) parts of CFRP waste. Herein, TDT was coupled with electrical treatment (ET) to improve the recycling performance of CFRP laminates waste. The tensile strength of the rCFs measured via the single-fiber tensile tests was analyzed using a two-parameter Weibull distribution. Absorbed water was preferentially evaporated from the laminates by Joule heating during ET, resulting in extensive pore formation. Following TDT, the oCFs and iCFs showed nearly identical average tensile strengths because the pores formed by ET served as efficient diffusion pathways for oxygen gas. The proposed recycling technology may potentially be applied to other types of moisture-absorption waste.