Effects of selective distribution of poly(methyl methacrylate)-grafted graphene oxide on the phase behavior and conductivity of poly(methyl methacrylate)/poly(vinyl acetate) blends

The effect of selective distribution of two kinds of poly (methyl methacrylate)-grafted graphene oxide (PMMA-g-GO) nanosheets (NSs) on the phase behavior and conductivity of PMMA/poly (vinyl acetate) (PVAc) blends is investigated. The grafting density and length of two modified GO NSs are different, resulting in their thermodynamic equilibrium location in the blend matrix, but their initial locations are both in the PVAc-rich phase with low viscosity. The PMMA-g-GO(6 k) NSs with the sparse mushroom-like grafted PMMA chains gradually migrate to the interface of blend matrix and aggregate to form the conductive network, resulting in the suppression of domain coarsening and long-term maintenance of co-continuous morphology. The grafted chains on the surface of PMMA-g-GO(58 k) NSs exhibit the screened wet brush and the PMMA matrix chains can penetrate with the grafted chains, resulting in the location in the PMMA-rich phase. Two modified GO NSs filled PMMA/PVAc nanocomposites can occur the conductive percolation and such activation energies are higher than those of flow for PMMA and PVAc, indicating that the interactions between modified GO and polymer components may restrict the aggregation of conductive modified GO NSs at the interface or in the PMMA-rich phase.