Effect of modified graphene on thermal, mechanical and tribological performance of polyimide based composites

The graphene oxide sheets (GO) were modified by silane coupling before incorporation into the aromatic polyimide (PI) matrix via in situ polymerization. The successful grafting of silane coupling onto the surface of the graphene was confirmed by FTIR, x-ray diffraction, and Raman spectroscopy. The incorporation of modified graphene oxide(K-GO) sheets significantly enhanced the thermal stability and tensile properties of PI. It was found that the tensile stress and the Young's modulus of 0.5 wt% K-GO/PI were increased by 27.2% and 28.0% from pure PI, respectively. The T-5% values of 0.5% K-GO/PI (507 degrees C) were obviously higher than that of pure PI (491 degrees C). Compared to pure PI, the PI composites with the K-GO addition of 0.5 wt% exhibits much lower friction coefficient (0.361) and wear rate (1.247 x 10(-5) mm(3) N(-1)m(-1)). This can be attributed to the enhanced effect of K-GO addition on the properties of the composites. This study aims to expand the range of applications of graphene and to solve wear-related mechanical failures for polymer parts.