Research On Structure Design And Properties Of Uv Resistant PBO Fiber

Poly(p-phenylene benzobisoxazole)(PBO)fiber has excellent strength,heat resistance and flame resistance.It is known as ‘the 21 Century Super Fiber'.It has potential and broad application prospects in aerospace,military and so on.However,PBO fiber is sensitive to UV radiation,which limits and reduces the application and value of PBO fiber.A kind of MOFs(UiO-66)was introduced on the surface of PBO fiber for improving UV resistance by sizing treatment.In this paper,the structure and properties of UiO-66 were characterized by optimizing the synthesis conditions and using SEM,TEM,FT-IR,PXRD,TGA and other tests.The results showed that the good eight-hedral morphology and crystalline UiO-66 nanocrystals could be obtained by microwave method.Secondly,the effect of different mass fraction of UiO-66 on the stability and heat resistance of sizing agent system were studied.Finally,using the sizing process,the composite UiO-66/epoxy sizing agent was coated to the surface of PBO fiber,and the modified PBO fibers with different mass fraction of UiO-66 were prepared.The influence of the surface properties of PBO fibers and the bonding properties of the epoxy resin matrix was analyzed.UV aging test was used to evaluate the UV resistance of PBO fibers modification.PBO fibers were characterized and analyzed by SEM,PXRD,TGA and other tests.The results show that UiO-66 nanocrystals have been introduced into the surface of PBO fibers by the sizing process,and there is no obvious aggregation phenomenon.Compared with the unmodified PBO fibers,the addition of UiO-66 improves the surface energy of the fiber and its interface with the epoxy resin matrix.In addition,the UV accelerated aging test and related tests showed that the tensile strength retention,surface morphology and structural integrity of the unmodified fibers in the same aging conditions.The results showed that UiO-66 nanocrystals were used in sizing with solid UV visible light diffuse reflectance test results.The treatment process can firmly adhere to the surface of PBO fiber and form a natural barrier,based on its own good UV absorption a nd shield ability,thus obviously improving the UV aging resistance of PBO fibers.