Synthesis, characterization and properties of graphene-reinforced polyimide coatings

Abstract

In this study, in order to achieve good dispersion of graphene in polyimide, graphene nanosheets were edge-aminated with L-phenylalanine (PheG). Then siloxane-capped polyamic acid (PAA-Si) was prepared by condensation of PMDA and ODA as well as subsequent modification with KH-550 to improve the adhesion between the material and the substrate surface. Polyimide/graphene (0.3–2.0 wt%) nanocomposites were prepared by solution blending of PAA-Si with PheG followed by thermal imidization. The structures of PheG and PAA-Si were verified by infrared spectroscopy, Raman spectroscopy and XPS. The microstructure analysis was performed by SEM and TEM to investigate the morphology of graphene in the polyimide matrix. The thermal, thermomechanical, and tribological properties of polyimide/graphene nanocomposites were investigated by TGA, DMA, and friction and wear tests. Because of their ease of preparation and superior physical properties over neat polyimide, the prepared polyimide/graphene nanocomposites showed promising applications as wear-resistant and self-lubricating materials.