Surface modification of PBO fiber by grafting nanoporous SiO2 coating with improved interfacial properties

PBO fiber has been valued for its excellent mechanical properties and is generally used as a reinforcement for resin-based fiber. However, as a result of its surface inertness, the degree of bonding of the PBO fiber between the resin is very low. The fibers in composites are easily pulled out, and their performance often falls short of expectations. Therefore, researching on the surface improvement of PBO fiber is essential. In this paper, silica coating with a nano-porous structure was grafted on the surface of PBO fiber by sol-gel method, using 3-glycidoxypropyltrimethoxysilane (GPTMS) as a silane coupling agent, and ethyl orthosilicate (TEOS) as silicon source. The PBO and modified PBO were characterized by Fourier transform infrared spectrum (FTIR), scanning electron microscopy(SEM), Energy dispersive spectrometer (EDS), Single-fiber microdroplet pull-out testing, Brunauer-Emmett-Teller (BET) characterization, tensile test and wettability test. The result showed that PBO/SiO2 fiber not only had good mechanical properties, but also owned superhydrophobic property. And it also revealed that the IFSS value of PBO/SiO2 fiber between epoxy resin was enhanced by 114.8% in the interfacial shear strength test. The importance and originality of this study is that it explores an efficient way to improve the adhesiveness between PBO fiber with resin.