Modification And UV-resistant Properties Researching Of PBO Fibers With ?-TDMACuPc

Poly-p-phenylene benzobisoxazole(PBO)fiber is widely used in various fields of social production and life for its excellent mechanical properties,chemical stability,and flame retardant and thermal insulation properties.These include reinforced parts of composite materials in the military field,heat-resistant materials under high-temperature conditions,and thermal insulation materials on engines.However,the problem of UV degradation and degradation of PBO fiber severely limits its application in outdoor or space environments.In this paper,PBO-?-TDMACu Pc fibers were prepared by in-situ copolymerization of ?-TDMACu Pc with PBO polymer for the purpose of improving the UV degradation resistance of PBO fibers.To ensure that the added ?-TDMACu Pc does not affect the bulk properties of the PBO fiber,it can improve the UV degradation and degradation of the PBO fiber.First,the optimal copolymerization temperature of ?-TDMACu Pc and PBO polymer was determined to be 140?.PBO fibers and a series of modified fibers with different contents of ?-TDMACu Pc were prepared.In order to study the effect of ?-TDMACu Pc addition on the bulk properties of PBO fibers,the intrinsic viscosity and tensile strength of the fibers were characterized.The results showed that the viscosity and strength of the modified fibers increased first and then decreased with increasing ?-TDMACu Pc content.In order to study the effect of ?-TDMACu Pc on the molecular structure and surface elements of PBO,using FT-IR and UV-Vis analysis,it was proved that ?-TDMACu Pc was polymerized into the PBO molecular chain.Through XPS analysis of the fiber surface elements,it was found that the content of C and N in the modified fiber was higher than that of PBO fiber.Second,in order to study the effect of ?-TDMACu Pc on the UV aging resistance of PBO fiber,the intrinsic viscosity and strength of the aged fiber were analyzed.The results showed that the intrinsic viscosity of PBO-2.0wt% ?-TDMACu Pc fiber was increased by 130% and the tensile strength increased by 55% compared with PBO fiber after 480 h UV aging.The surface morphology analysis and crystal surface structure analysis of the aged fiber shows that the more ?-TDMACu Pc content,the weaker the surface damage of the fiber after aging,the addition of ?-TDMACu Pc protects the fiber crystal structure from ultraviolet light damage..The TG and DTG tests were performed on the aged fibers.The results showed that the initial decomposition temperature of the modified fibers increased by 40? after 480 hours of UV aging,and the maximum decomposition temperature increased by 55?.Finally,the aging degradation kinetics behavior of PBO was studied and its aging degradation kinetics equation of composite first-order reaction was found.The degradation degradation rate k at 30?,50?,70? and 90? was obtained.The results show that the aging degradation rate of PBO fiber accelerates with the increase of temperature,and the aging activation energy Ea of the fiber is obtained by the Arrhenius formula.Through experimental analysis,it was found that ?-TDMACu Pc absorbs and releases UV energy using a high-efficiency energy-dissipation mechanism without radiation(proton transfer in intramolecular hydrogen bonding).