Abstract: Expandable graphite was prepared from natural flake graphite via chemical oxidation and high temperature processing. Via situ polymerization of styrene in presence of expanded graphite polystyrene-expanded graphite (PS-EG) composites were obtained. Melt blending PS-EG with neat polystyrene leading to polystyrene/polystyrene-expanded (PS/PS-EG) composites. The mechanical properties, thermal stability, and the microstructure of the composites were studied. The impact strength，thermal stability were improved with the adding of PS-EG. Compared with the neat polystyrene, the impact strength of PS/PS-EG composites was improved 63.4 %, when the content of PS-EG was 9 %, however the tensile strength showed a large decreasing. Micro-analysis showed that expanded graphite dispersed homogeneously in the form of vermiculate in the composites, and the existence of PS-EG increased the interface effect of the PS/PS-EG composite, the cross section of composites displayed a pinhole structure.

Key words: expanded graphite, polystyrene, in situ polymerization, intercalation, composite