Research On Re-resource Of Recycling Carbon Fiber Composites Under Supercritical Water And N-Butanol Mixture

Recycling and reusing of carbon fiber reinforced polymer(CFRP)is the key measure to sustainable application of advanced composites,and recycling of high performance carbon fibers from waste CFRP has great economic and environmental significance.This article proposed and investigated recycling method,process and re-resource of waste CFRP based on experimental research,and analysed environmental impact of recycling waste CFRP process based on theoretical research.The main research contents include the following four aspects:(1)Degradation experiments of epoxy resin were designed and carried out under supercritical water,supercritical alcohols,supercritical water/alcohol mixture.Degradation ability of supercritical alcohols and supercritical water/alcohol mixture was compared by degradation rate of epoxy resin,its results are as follows: supercritical water/n-butanol mixture > supercritical Water/n-propanol mixture > supercritical water/ethanol mixture > supercritical water/methanol mixture.(2)The effects of process parameters on degradation of epoxy resin were analyzed by using supercritical water/n-butanol mixture,and general rule of degradating epoxy resin was revealed.The process parameters,including temperature,time,catalyst concentration,volume ratio,have little effect on mechanical properties of recycled CF,the tensile strength and modulus retention rates of recycled CF are above 93% and 91%,respectively.The optimum recovery process is as follows: temperature is about 340 ~ 350?,time is about 30 ~ 40 min,catalyst concentration is about 0.010 ~ 0.020mol/L,volume ratio of water/alcohol is about 30%~50%,and degradation rate of epoxy resin is over 92% under this process parameters.(3)The effects of CF length and content on mechanical properties of recycled CF reinforced thermoplastic products were analyzed.Interfacial properties between recycled CF and matrix materials were investigated by means of SEM and testing of tensile strength.When CF length is 6mm and CF content is 10%,comparing with pp,the tensile strength,bending strength and impact strength of original CF and recycled CF reinforced thermoplastic products are increased by 74.40% and 29.96%,88.12% and 53.94%,and 269.10% and 125.69%,respectively.(4)The environmental impact of recycling process of waste CFRP was investigated by LCA.CF manufacturing and waste CFRP recycling phase are main phase of environmental impacts,and the key factor of main phase is power consumption.There are mainly three types of environmental impacts: GWP 100 years,Abiotic depletion fossil,Marine aquatic ecotoxicity pot.The environment impact assessment provides a theoretical basis for large-scale industrial recycling waste CFRP,greenly and efficiently.