Dispersion Polymerization of Methyl Methacrylate in Supercritical Carbon Dioxide: An Investigation into Stabilizer Anchor Group

Abstract

New stabilizers for the dispersion polymerization of methyl methacrylate (MMA) in supercritical carbon dioxide (scCO2) were prepared and studied in terms of their anchor group architecture. The same perfluoropolyether (PFPE) chain was used in each case as the CO2-philic portion of the stabilizer and four different PMMA-philic headgroups were investigated as anchoring units: an alcohol, an acetate group, a methacrylate unit, and a PMMA block. When compared to the stabilizing ability of PFPE−alcohol, incorporation of an anchor group as small as an acetate group, or a reactive group such as a methacrylate unit, was found to have a dramatic effect upon the dispersion polymerization of MMA in scCO2. Their incorporation led to a significant increase in PMMA yield and molecular weight and an improvement of the morphology of the polymer product. A method for the synthesis of PFPE-b-PMMA diblock copolymers is reported via atom transfer radical polymerization (ATRP) from a PFPE−bromoester macroinitiator in a fluor...