Flexible graphene polyimide nanocomposites (0.1鈥? wt %) with superior mechanical properties over those of neat polyimide resin have been prepared by solution blending. Imide moieties were grafted to amine-functionalized graphene using a step-by-step condensation and thermal imidization method. The imide-functionalized graphene exhibited excellent compatibility with
N-methyl-2-pyrrolidone. The dynamic storage moduli of the graphene polyimide nanocomposites increased linearly with increasing graphene content for both unmodified graphene and imidized graphene. Moduli of the imidized graphene nanocomposites were 25鈥?0% higher than those of unmodified graphene nanocomposites. Both neat polyimide and polyimide nanocomposites exhibited shape memory effects with a triggering temperature of 230 掳C. where addition of graphene improved the recovery rate. Addition of graphene improved thermal stability of the polyimide nanocomposites for both graphene and modified graphene.
Keywords:
graphene; polyimide nanocomposites; shape memory polymers; mechanical properties; thermal stability; exfoliation