Study on the Mechanical Properties of PEPA Grafted TiO ₂ /CNT/Carbon Fiber/Polyimide Composites

ABSTRACT Pentaerythritol phosphate (PEPA) grafted TiO 2 and CNT were coated layer by layer onto the surface of carbon fibers to reinforce polyimide (PI) composites. The effect of PEPA grafted TiO 2 and CNT on the mechanical properties of CF/PI composites was studied by scanning electron microscope, contact angle measurement and X‐ray photoelectron spectroscopy. The results show that PEPA grafted TiO 2 and CNT can significantly increase the surface activity and specific surface area of carbon fiber, and improve the wettability, reactivity and mechanical meshing between resin and carbon fiber. The interfacial properties and mechanical strength of the composites are improved. The interlaminar shear strength (ILSS) and flexural strength of PEPA grafted TiO 2 /CNT composite grafted carbon fiber composites were increased by 96.2% and 89.7%, respectively.