Fabrication of polystyrene/nano‐<scp>C</scp>a<scp>CO</scp>₃ foams with unimodal or bimodal cell structure from extrusion foaming using supercritical carbon dioxide

Abstract

The article surveyed the fabrication of polystyrene (PS)/nano‐CaCO 3 foams with unimodal or bimodal cellular morphology from extrusion foaming using supercritical carbon dioxide (sc‐CO 2 ). In order to discover the factors influenced the cell structure of PS/nano‐CaCO 3 foams, the effects of die temperature, die pressure, and nano‐CaCO 3 content on cell size, density, and morphology were investigated detailed. The results showed that the nano‐CaCO 3 content affected the cell size and morphology of PS/nano‐CaCO 3 foams significantly. When the die temperature and pressure was 150°C and 18 MPa, respectively, the foams with 5 wt% nano‐CaCO 3 exhibited the unimodal cellular morphology. As the nano‐CaCO 3 content increased to 20 wt%, a bimodal cell structure of the foams could be obtained. Moreover, it was found that the bimodal structure correlated more strongly with the pressure drop than the foaming temperature. The article revealed that unimodal or bimodal cellular morphology of PS/nano‐CaCO 3 foams could be achieved by changing the extrusion foaming parameters and nano‐CaCO 3 content. POLYM. COMPOS., 37:1864–1873, 2016. © 2015 Society of Plastics Engineers