Plasticization of polymers with supercritical carbon dioxide: Experimental determination of glass-transition temperatures

High-pressure partition chromatography, a modification of the inverse gas chromatography technique, is presented as suitable technique for the study of the plasticization effect of carbon dioxide on the following polymers: poly(methyl methacrylate), polystyrene, and bisphenol A-polycarbonate. Polymers in the presence of a compressed gas or a supercritical fluid become plasticized; this means that their glass-transition temperatures (T-g's) can be lowered by 10s of degrees, which causes changes in their mechanical and physical properties. CO2-induced plasticization has an important impact on many polymer processing operations in which the T F depressions of the polymers can be evaluated. The experimental results are discussed and compared with data available from literature for each polymer we considered. (C) 2003 Wiley Periodicals, Inc.