Preparation and properties of poly(propylene-g-maleic anhydride) filled with expanded graphite oxide

Poly(propylene-g-maleic anhydride) (PPMA) layered expanded graphite oxide (EGO) (PPMA–EGO) composites were prepared by melt dispersion in an internal shear mixer. EGO influenced crystalline structure, thermal and dynamic thermomechanical properties of PPMA–EGO composites. Wide-angle X-ray diffraction revealed no change in d spacing of EGO. Crystallization temperature increased, due to heterogeneous nucleation by EGO. Thermogravimetry demonstrated enhanced thermal stability, due to thermal insulation, adsorption of PPMA degradation products and a tortuous path for escaping vapors. Dynamic mechanical analysis showed that the EGO in PPMA matrix provided modulus reinforcement and increased glass transition temperature. These enhancements were attributed to interactions and potentially bond formation between EGO and the maleic anhydride of PPMA. Electrical conductivity of PPMA–EGO increased at 3%·W/W of EGO indicating a percolation threshold that can lead to semi-conductor application.