Fabrication of polyethylene/graphite nanocomposite from modified expanded graphite

A novel process was employed to fabricate a polymer/expanded graphite nanocomposite by modifying the conducting filler expanded graphite (EG) with unsaturated polyester resin (UPR). The modified expanded graphite (MEG) was prepared from EG in which the graphite nanosheets, already present in EG, were wrapped and isolated by the UPR during processing. The as-prepared MEG was reduced to powder form to improve its dispersion in the matrix. MEG powders were embedded into a high-density polyethylene (HDPE) matrix via melt-extrusion in a single-screw extruder to prepare the conducting composite. The as-prepared HDPE/EG conducting composite exhibited a low percolation threshold of similar to 5.7 wt% due to the high aspect ratio of graphite nanosheets. Mechanical properties such as the tensile and impact strength were also studied. Scanning electron microscopy was used to characterize the microstructure of EG, MEG powder and the resulting nanocomposites. (C) 2006 Society of Chemical Industry.