Preparation and Properties of Polypropylene Nanocomposites Reinforced with Exfoliated Graphene

Abstract

We have prepared a series of polypropylene/exfoliated graphene (PP/EG) nanocomposite films via efficient melt-compounding and compression, and investigated their morphology, structures, thermal transition behavior, thermal stability, electrical and mechanical properties as a function of EG content. For the purpose, EG, which is composed of disordered graphene platelets as reinforcing nanoscale fillers, is prepared by the oxidation/exfoliation process of natural graphite flakes. SEM images and X-ray diffraction data confirm that the graphene platelets of EG are well dispersed in PP matrix for the nanocomposites with EG contents less than 1.0 wt%. It is found that thermo-oxidative degradation of PP/EG nanocomposites is noticeably retarded with the increasing of EG content. Electrical resistivity of the nanocomposite films was dramatically changed from similar to 10(16) to similar to 10(6) Omega.cm by forming electrical percolation threshold at an certain EG content between 1 and 3 wt%. Tensile drawing experiments demonstrate that yielding strength and initial modulus of PP/EG nanocomposite films are highly improved with the increment of EG content.