Tensile property of surface-treated poly-p-phenylenebenzobisoxazole (PBO) fiber-reinforced thermoplastic polyimide composite

Abstract

The current study examined the effect of rare earth (RE) solution surface modification of poly- p-phenylenebenzobisoxazole (PBO) fibers on the tensile property of PBO fiber-reinforced thermoplastic polyimide (PBO/PI) composites. Experimental results revealed that RE surface treatment could effectively improve the interfacial adhesion between PBO fibers and PI matrix. Compared with the untreated and coupling agent-treated PBO/PI composite, the RE-treated composite had better interfacial adhesion. For RE-treated PBO/PI composites, the tensile strength and tensile modulus varied with RE concentrations, and the optimum value was obtained at 0.6 wt% of RE concentration. The fracture surface morphologies of the samples were investigated by scanning electron microscopy (SEM) to analyze the effect of various surface treatments. X-ray photoelectron spectroscopy (XPS) study of PBO fibers surface showed that the ratio of oxygen/carbon on the surface of PBO fibers was obviously increased after RE treatment, which indicated the content of polar groups on the surface of PBO fibers increased compared with the others. The increase in the amount of polar groups strengthened the interfacial adhesion between PBO fibers and PI matrix and accordingly enhanced the tensile properties.