Abstract: In this paper, microcellular polyphenylene sulfide (PPS) foam was prepared via injection molding using supercritical N2 (SCN2) as a foaming agent. Effects of mould runner, content of SCN2, and shot size on cell properties, relative density, mechanical properties, and dielectric properties of microcellular PPS foams were studied. It showed that the cell size was enlarged and the density was decreased with increasing mould runner. The content of SCN2 had little influence on the pore size, mechanical and dielectric properties, however, increased the density of the cells. Meanwhile, the shot size also played an important role in the properties of PPS foams. The lower shot size, the lower relative density, mechanical properties and dielectric constant of microcellular PPS foams were.

Key words: polyphenylene sulfide, injection molding, microcellular foaming, supercritical nitrogen