Polymerisation of methyl methacrylate in supercritical difluoromethane

Abstract

The use of supercritical difluoromethane (scHFC 32) as a solvent is demonstrated for the polymerisation of methyl methacrylate. It is shown that appreciably higher molecular weight polymer can be obtained using scHFC 32 than scCO₂, which is due to the higher solubility of the polymer in the more polar fluid. The solubility of various polymer standards is characterised at two pressures in scHFC 32 and is shown to be appreciable up to a molecular weight of 11 000 g mol⁻¹ whereas in scCO₂ the polymer of this mass is shown to be almost totally insoluble.