Foam processing and cellular structure of polycarbonate-based nanocomposites

Via a batch process in an autoclave, foam processing if intercalated PC/clay nanocomposites, having different amount of clay, has been conducted using supercritical CO2 as a foaming agent. The cellular structures obtained from various foaming temperature-CO2 pressure ranges were investigated by SEM. The incorporation with nanoclay-induced heterogenous nucleation occurs because of a lower activation energy barrier compared with homogenous nucleation as revealed by the characterization of the interfacial tension between bubble and matrix. The controlled structure of the PCCN foams changed from microcellular (d congruent to 20 mu m and N-c congruent to 1.0 x 10(9) cells (.) cm(-3)) to nanocellular (d congruent to 600 nm and Nc congruent to 3.0 x 10(13) cells (.) cm(-3)). The mechanical properties of PCCN foams under compression test were discussed.