The Research Of T700 Carbon Fiber/Epoxy Resin Composites By Catalytic Pyrolysis

With the development and progress of science and technology,carbon fiber reinforced resin composite (CFRP) has been applied in the fields of aerospace, automobile production, sports equipment and other fields due to its high strength and high modulus, light weight, corrosion resistance and other excellent properties. At the same time, in the process of manufacture and use, the generation of CFRP waste can grow rapidly.Because the high value of carbon fiber in CFRP, if the waste was treated simply, it will not only cause an enormous waste of resources, but also have an adverse effect on the environment. Therefore, the recycling of carbon fiber in CFRP waste has become an urgent research topic.In this paper, based on the analysis of the current domestic and foreign CFRP waste recycling methods, the research of pyrolysis that is the current most likely to achieve the industrial production method was carried out. Firstly, the thermal degradation kinetics, thermal degradation products and mechanism of T700 carbon fiber / epoxy resin composites were studied. The results show that the existence of carbon fibers and the different degradation atmosphere and temperature had an effect on the degradation kinetics of epoxy resin matrix and lead to different degradation products. The effects of temperature, time and atmosphere on the pyrolysis and the properties of carbon fibers were studied by pyrolyzing CFRP in a thermal reactor. The analysis showed that the surface of recycled carbon fiber that was pyrolyzed at 500℃ for 30min in air or two-step pyrolysis of at 450 °C for 30min in air after 600℃ for 10min in nitrogen almost did not exist residual resin. With under different thermal degradation process, the characterization of XPS and Raman indicated that the oxygen functional groups on the surface of carbon fibers had some change and the structures of the lattice of carbon atoms were not obviously affected. About the mechanical properties of carbon fiber, retention rate of tensile strength of single fiber was 90% which was two steps pyrolyzed, which was much higher than that of disposable pyrolysis, and the retention rate was 80%. The interlaminar shear strength of recycled fibers was only 75%, which indicated that the interfacial bonding between fiber and resin was reduced to a great extent.Based on the above research work, in order to reduce the epoxy matrix degradation temperature or time, this paper selected several kinds of room temperature solid catalyst. The research of the kinetics of catalytic pyrolysis and the difference of pyrolysis products, and the improvement effect of catalyst on the degradation temperature and time were studied. The results indicated that the zinc chloride as catalyst could promote the chemical bond scission between nitrogen and benzene ring in the resin matrix, which results in the decrease of the activation energy and the great differences of degradation products. When the thermal degradation temperature was reduced to 400 ℃ and the time was 3 Omin,there were no residual resin on the surface of the fibers. The characterization of XPS and Raman indicated that the oxygen functional groups on the surface of carbon fibers had some change and the structures of the lattice of carbon atoms were not obviously affected. The tensile strength of catalytic pyrolysis recycled carbon fibers retention rate reached 94%. The interlaminar shear strength retention rate of unidirectional composites materials were prepared with epoxy resin and recycled carbon fibers was 81%.