Promoting compatibilization effect of graphene oxide on immiscible PS/PVDF blend via water-assisted mixing extrusion

Polystyrene/poly(vinylidene fluoride)-graphene oxide (PS/PVDF-GO) blend nanocomposites are prepared via injecting GO suspension into the blend melt during one-step water-assisted mixing extrusion (WAME). The fined PVDF domains and increased elongations at break for the PS/PVDF-GO blend nanocomposites demonstrate that the GO acts as a compatibilizer for the blend. The compatibilization effect of the GO is promoted by the injected water because it facilitates the migration of the GO layers in the PS phase to the interfaces between the PS and PVDF phases during melt mixing. The compatibilization effect of the GO on the PS/PVDF blend can be explained by good interfacial interactions between the oxygen-containing groups at the GO surface and the >CF2 groups in the PVDF and between the basal planes of GO layers and the phenyl rings of PS, and the coalescence suppression effect of the PVDF domains due to the steric hindrance. The compatibilization and reinforcement effects of the GO layers increase the tensile strength, Young's modulus, elastic modulus and complex viscosity of the PS/PVDF blends.