Improvement of mechanical, thermal and tribological properties of (3-aminopropyl) triethoxysilane-modified graphene/polyimide nanocomposites by in situ polymerisation

To elucidate the improvement and the principle of graphene modification on the polyimide (PI), (3-aminopropyl) triethoxysilane-modified graphene (PMG), was designed and prepared by anchoring the (3-aminopropyl) triethoxysilane (APTS) chain on the graphene sheet surface, and used to synthesise PI composites by in situ polymerisation. The unique surface modification significantly improved the compatibility and dispersion of graphene in the PI matrix. Tensile strength and Young’s modulus of 1.0PMG/PI was 109.45 MPa and 1.73 GPa, which increased by 54.26 and 86.02% from neat PI, respectively. The tribological properties and mechanism were also discussed. The friction coefficient and wear rate of 1.0PMG/PI (0.287, 2.291×10−5mm3 Nm−1) decreased by 47.53% and 35.06%, respectively. This improvement of the tribological properties was mainly caused by the cooperative interaction of the improved mechanical and thermal properties of the composites and the high self-lubricity of modified graphene.