Free-radical polymerization of styrene in CO2/ethanol mixed supercritical fluid

The free-radical polymerization of styrene has been studied in CO2/ethanol mixed supercritical fluid. Depending on the experimental conditions, yields varied from low to fairly good (around 60%). The polymers exhibited molar masses ranging from 5 000 to 26 000 g/mol. The results obtained were compar ed with those generated in the presence of mesitylene or pure ethanol used as solvent. In particular, it was observed that the thermal polymerization of styrene in the supercritical fluids or in ethanol was somewhat inhibited as compared to that occurring in mesitylene. Indeed, almost no thermal pol ymerization could be observed in these conditions.