Crosslinked POSS-decorated graphene oxide for improving the friction and wear properties of polyimide composite

Designing nanoflakes with advantageous three-dimensional cross-linked structures is one of the effective measures to improve reinforcement performance. Herein, crosslinked “fish-net” shaped octaglycidylether polyhedral oligomeric silsesquioxane-functionalized graphene oxide (OGPOSS-GO) was prepared to obtain polyimide (PI) composites coatings with both wear-resistant and corrosion resistance. GO/PI and uncrosslinked monoaminopropylisobutyl POSS (MAPOSS) were obtained using the same methods for comparative explorations. The results show that incorporating OGPOSS-GO into PI resin improve the hardness, wear resistance and corrosion resistance of PI, with enhancement effects far superior to those of the uncrosslinked MAPOSS-GO. MD simulations corroborate the experimental observations and further elucidate the mechanism behind the superior reinforcing properties of OGPOSS-GO by analyzing changes in energy, structure, density, stress, and diffusion rate during friction and corrosion processes. The study found that OGPOSS-GO, with its three-dimensional cross-linking structure, can bind more PI chains through a “fish-net” structure, achieving self-binding effects that increase coating density, thereby improving the hardness, tribological properties and corrosion resistance of the coating. Our study provides new insights into the molecular structure design of nanoflakes.