초임계이산화탄소에서 계면활성제를 이용한 분산중합 및 이에 의한 무기/유기 복합체 제조

Abstract

Since Carbon Dioxide (CO₂) is a good solvent for most liquid vinyl monomers and a poor solvent for most polymers, it has been used as a medium for dispersion polymerization. It has unique characteristics such as high diffusivity, liquid-like density, zero surface tension, low viscosity, high fast mass transfer and tunable solvent power. In addition, it is inexpensive, recyclable, non-flammable and non-toxic. It also has advantage of easy separation from products and resolves problems related to solvent removal. In this paper, we report the dispersion polymerization of styrene using poly(dihydroperfluorooctyl methacrylate-co-dimethylaminoethyl methacrylate) (p(FOMA-co-DMAEMA)) copolymers synthesized in this study as a stabilizer in scCO₂. The effects of varying the concentrations of stabilizer and monomer, reaction pressure upon the polymerization yield, molar mass and morphology of the resulting polystyrene (PS) have been explored. Inorganic/organic composites are expected to combine the physical properties of the inorganic particles with the processability and the flexibility of the polymer matrix. PS encapsulated silica particles were synthesized by the dispersion polymerization of styrene in scCO₂. The method involves the dispersion polymerization of styrene using poly(heptafluorobutyl methacrylate-co-diisopropylaminoethyl methacrylate) (p(FBMA-co-DPAEMA)) copolymer as the stabilizer in the presence of well dispersed silica nanoparticles which were surface functionalized with the silane coupling agent bearing a polymerizable group. The spherical SiO₂/PS nanocomposites were successfully synthesized by the dispersion polymerization of styrene in scCO₂ using copolymeric stabilizers.