Recovery of carbon fibers from carbon fiber / epoxy composites by epoxy degradation with concentrated zinc chloride in ethanol

Concentrated zinc chloride in ethanol was used to decompose the epoxy in carbon fiber / epoxy (CF / EP) composites to recover carbon fibers. Factors affecting the degradation rate such as reaction temperature and zinc chloride concentration were investigated. The properties of the products decomposed by epoxy and the recovered carbon fibers were characterized. Results indicated that the molecular weight of the decomposed epoxy decreased and its solubility in ethanol increased with the reaction time. A significant fraction of the C—O bonds in epoxy is broken down by the degradation. The strength of the recovered fibers is 97. 1% of the original ones and their microstructure was only slightly changed, but the amount of the oxygen-containing functional groups on the surface of the recovered fibers decreased.