Study On CNTs Irradiation Grafting PBO Fiber And Composite Interfacial Properties

Poly(p-phenylene benzobisoxazole) (PBO) fiber surface was modified by CNTs irradiation grafting using 60Coγ-ray irradiation grafting technology. The surface roughness and the chemical activeness of PBO fiber were modified, and the interface adhesion properties between the fiber and the resin matrix were improved, too. It is realized that fiber surface is modified without losing fiber strength by means of optimum design of irradiation processing parameters and grafting monomer. All these factors result in the the increasing of integrated properties of PBO fiber composites.Established irradiation technology parameters: radiation dose 60kGy, dos-e rate 4.8kGy/h; irradiation grafting monomer CNTs, 1% of the CNTs/epichl-orohydrin hybrid graft system.The comprehensive evaluation of modification effect ofγ-ray irradiated PBO fiber has been done by X–ray photoelectron spectroscopy (XPS), capillary method, atomic force microscopy (AFM), Microbond method, scanning electron microscopy (SEM), and tensile strength test, respectively. The results indicate that the chlorine content and carbon of CNTs on the surface of the irradiated PBO fiber increase, and the wettability of CNTs irradiated PBO fiber have greatly increased compared to the untreated fiber. The surface morphology of the irradiated PBO fiber becomes rougher than the untreated fiber. The interfacial shear strength (IFSS) between PBO fiber and epoxy resin at 60kGy is 133% higher than the untreated PBO fiber composite, and the improved interfacial adhesion resulted in a change in the failure mode of the composite from an adhesive-type interfacial failure to a cohesive-like matrix failure. The effects of irradiation at 60kGy on the tensile strength and the structure of PBO fiber are not significant. In fact, there is only 3% decrease of the tensile strength of PBO fiber at 60kGy irradiation compared with the untreated fiber.