THE STUDY ON GRAPHENE OXIDE AS A HETEROGENEOUS NUCLEATION AGENT IN SUPERCRITIAL CARBON DIOXIDE FOAMING

摘要

Graphene oxide (GO) was prepared by oxidation of graphite using the Hummers method, and was modified by isocyanate to obtain dispersed GO sheets in dimethylformamide. Polystyrene (PS)/GO composites were prepared by solution blending, and their morphologies and properties were characterized. The addition of GO increased the glass transition temperature, storage modulus, and thermal stability of the composites compared with PS. Foams of PS and PS/GO composites were prepared by supercritical carbon dioxide foaming. The composite foams exhibited slightly higher cell density and smaller cell size compared with the PS foam, indicating the GO sheets can act as heterogeneous nucleation agents.