Synthesis of Poly(styrene-co-acrylonitrile)/CIay Nanocomposites in Supercritical Carbon Dioxide

摘要

Poly(styrene-co-acrylonitrile)/fluorinatedmontmorillonite was successfully prepared in supercritical carbon dioxide (scCO2) by dispersion polymerization. In this study, a mixed stabilizer system was applied and investigated. Poly(styrene-r-acrylonitrile)-block-poly(1,1,2,2-tetrahydroperfluorooctylmemacrylatB)(PSAN-b-PFOMA)was synthesized and investigated as stabilizer in scCO2. Fluorinated surfactant was used for the modification of the montmorillonite. The fluorinated montmorillonite (FMMT) applied in the polymerization was not only used as nanocomposite filler but also as a guest stabilizer. This study examined the stabilization roles of stabilizer and guest stabilizer respectively. The optimum dosages of both compounds were studied. The polymerization with mixed stabilizer resulted in high yield and high molecular weight. Moreover, a series of nanocomposites were characterized and the products showed excellent properties. It was found that the montmorillonite layer could be completely exfoliated using reasonable loading, and dispersed in the polymer matrix. In addition, the pressure of scCO2 was studied and the density of scCO2 was shown to be relevant to the stabilization of the reaction. The mixed stabilizer system made the polymerization more effective and the in-situ dispersion polymerization performed in scCO2 was shown to be a useful method for the nanocomposites preparation.