Preparation of organoclay, its copolymerization with MMA, and use to produce PVC nanocomposites

Two quaternary ammonium compounds with polymerizable vinyl group were designed and synthesized for use as clay modifiers. Copolymerization of quaternary ammonium compounds modified MMT platelets with methyl methacrylate was studied under a range of different reaction conditions and two kinds of polymeric surfactant-modified MMTs were prepared. These polymeric surfactant-modified MMTs were introduced to produce a series of PVC/MMT composites by melt compounding. XRD, TEM, and TGA confirmed that the better organic coverage of the platelets and the bigger interlayer spacing could be obtained for the copolymer of long-chain quaternary ammonium compounds modified MMT and methyl methacrylate (PMMA-H-MMT). The platelet fillers with better organic coverage represented much more useful functional fillers than the conventional ammonium-treated fillers due to their potential to exfoliate to a greater extent when melt-compounded with the PVC matrices. The experiment proved that PMMA-H-MMT shows better performance in increasing thermal stability of PVC/MMT composites.