New Process for Synthesizing Fluorinated Polymers in Supercritical Carbon Dioxide

Abstract

The typical polymerization process in supercritical fluids (SCFs) was improved through modifying the reaction system and designing and using sampling tubes. The efficacy of the newly developed procedure was demonstrated by the free radical homopolymerization of 2,2,2-trifluoroethyl methacrylate (TFEMA) and coplymerization of TFEMA and N-vinylpyrrolidone (NVP) in supercritical carbon dioxide (scCO2). Results indicate that the newly developed procedure has the characteristics of minimum loss of reactants and polymerization starting at the desired temperature and pressure. Furthermore, the polymerization process can be well tracked by analyzing the reaction mixtures online sampled from the reactor at certain reaction times by FT-IR, 1H NMR, and GPC. The reaction time and the product properties can be optimized based on the tracking results. For the first time, block copolymers by free radical polymerization in scCO2 was successfully synthesized by sequential addition of TFEMA and methyl methacrylate (MMA) in...