Stabilizer architectures based on fluorinated random and block copolymers for the dispersion polymerization of 2-hydroxyethyl methacrylate in supercritical carbon dioxide

Different types of stabilizers architectures based on copolymers composed of hydrophilic components and CO2-philic fluorinated acrylate groups were investigated for the free radical dispersion polymerization of 2-hydroxyethyl methacrylate (HEMA) at 65 C in supercritical carbon dioxide (scCO2). Four categories of random and block copolymeric stabilizers consisting of 1H,1H,2H,2H-perfluorooctyl methacrylate (FOMA), oligo( ethylene glycol) methacrylate (OEGMA), dimethyl amino ethyl methacrylate (DMAEMA), and ethylene oxide (EO) were selected as stabilizers for HEMA. The effect of the stabilizer architecture on the polymerization results was investigated in terms of stabilizer concentration, the nature of the hydrophilic anchor groups, and block versus random copolymers. White free-flowing poly(HEMA) powders in high yield were obtained with all stabilizers. While the monomer conversion was independent, the morphology of particles was found to be considerably affected by the nature of the stabilizers.