Molecular dynamics simulation of epoxy resin modified by polyimide grafted graphene oxide

To improve the adhesive performance of epoxy, some modification was conducted for pure epoxy. First, the models of physical blending of polyimide (PI) and graphene sheet (GNS), as well as polyimide (PI) grafted graphene oxide (GO) modified epoxy resin, were established using molecular dynamics (MD) simulations, along with pure epoxy resin, aiming to thoroughly investigate the effects of these two types of modification on the mechanical, thermal properties and adhesive properties of the epoxy resin. Importantly, three-layer adhesive models of Cu-epoxy-Cu were constructed, and the tensile simulation was carried out to explore the influence of the two modifications on the adhesion strength. The dynamic evolution process and micro information in the tensile process was observed and extracted to reveal the strengthening mechanism of PI grafted GO modified epoxy resin from nano-scale. The study showed that the epoxy resin modified with PI grafted GO has better mechanical and adhesive properties compared with PI-GNS blending. The glass transition temperature (Tg) of PI grafted GO was increased by 40 K and the thermal conductivity was increased by 0.16 W/(m center dot K). This study provided the theoretical guidance for enhancing adhesive strength of epoxy resin. Highlights center dot Three-dimensional crosslinked model of epoxy resin was constructed. center dot Mechanisms of polyimide grafted graphene oxide on epoxy resin revealed. center dot Three-layer models study modified epoxy resiny adhesion properties. center dot Adhesion mechanism of epoxy resin revealed from energy perspective.