Application of supercritical water for green recycling of epoxy-based carbon fiber reinforced plastic

• Published in: Composites science and technology 2019-03, Vol.173, p.66-72
• Main Authors: Kim, Young Nam, Kim, Young-O., Kim, Seong Yun, Park, Min, Yang, Beomjoo, Kim, Jaewoo, Jung, Yong Chae
• Format: Article
• Language: English
• Subjects: Carbon fiber reinforced plastic; Carbon fiber reinforced plastics; Carbon fibers; Carbon-epoxy composites; Catalysts; Decomposition; Electrical properties; Electrical resistivity; Epoxy; Epoxy resins; Fiber composites; Fiber reinforced plastics; Fiber reinforced polymers; Polymerization; Polymers; Pyrolysis; Recycle; Recycling; Reinforced plastics; Supercritical fluid; Supercritical fluids; Terephthalate; Thermal conductivity; Thermoplastic resins; Water reuse
• ISSN: 0266-3538; 1879-1050
• DOI: 10.1016/j.compscitech.2019.01.026

The objective of this study is to fabricate conductive carbon fiber composites with thermal and electrical properties by degradation carbon-fiber-reinforced plastics (CFRPs) and recycled carbon fibers using only supercritical water without any catalyst or oxidant. We focused on a recycling method that is harmless to the human body and environment-friendly, by using supercritical fluid water rather than recycling CFRP by physical or pyrolysis methods. In particular, we recycled carbon fibers (R-CFs) in which up to 99.5% of epoxy resin was removed, by optimizing the conditions of supercritical fluid water (SCF-W) treatment, and we fabricated conductive R-CFs composites with thermal and electrical properties by combining the R-CFs with cyclic butylene terephthalate (CBT), which is a polymerizable low-viscosity thermoplastic resin. The fabricated composites had a thermal conductivity of 1.35 ± 0.05 (W/mK) and an electrical conductivity of 11.23 × 10−6 (S/cm) when the added amount of recycled carbon fibers was 5 wt%. [Display omitted]