Degradation of Carbon Fiber-reinforced Polymer Using Supercritical Fluids

The degradation capability of the different supercritical fluids on carbon fiber-reinforced polymer (CFRP) was analyzed based on the impact of reaction temperature and time on degradation rate; the chain scission reaction of cross-linked network in CFRP occurred in supercritical fluid was investigated based on the analysis of liquid phase products; and the recycled carbon fiber under supercritical n-butanol and n-propanol were characterized. The results indicated that supercritical n-butanol had the excellent degradation capability on CFRP, followed by supercritical acetone. The degradation capability of supercritical ethanol and n-propanol on CFRP had little difference in temperature ranged from 280 degrees C to 340 degrees C, while supercritical n-propanol was superior to ethanol under the temperature ranged from 340 degrees C to 360 degrees C. The supercritical methanol and isopropanol were disadvantageous to CFRP degradation. The liquid phase products were main the benzene derivatives and phenol derivatives by the scission of C-C, C-O and -O- bond in linear chain segment, as well as that of C-N bond in cross-linked segment of epoxy resin cure system. In comparison with the original carbon fiber, the content of N, O and Si from the recycled carbon fiber surface decreased, while the content of C increased, and the tension strength can retain above 98 % of that of the original carbon fiber.