Exfoliated syndiotactic polystyrene-graft-poly (methyl methacrylate)/montmorillonite nanocomposite prepared by solvent blending

This study aims to explore an effective route for the graft copolymerization of methyl methacrylate (MMA) monomer onto syndiotactic polystyrene (sPS) using free-radical polymerization, and the effects of an organophilic montmorillonite on the final properties of graft copolymer samples. For this purpose, the chlorine groups of a-phenyl-chloro-acetylated sPS were converted to 9-decen-1-oxy groups by a substitution nucleophilic reaction in the presence of a solvent composed of 9-decen-1-ol moiety, sodium hydride (NaH) and dry N,N-dimethylformamide. The vinyl-terminated sPS multicenter macromonomer (VsPSM) obtained was used in free-radical copolymerization with MMA monomer in a heterogeneous process to yield a graft copolymer (sPS-graft-poly(methyl methacrylate) (sPS-g-PMMA)). The structure of VsPSM and sPS-g-PMMA were determined by (1)H nuclear magnetic resonance and Fourier transform infrared spectroscopy. Thereafter, organophilic MMT was obtained after being treated with hexadecyl trimethyl ammonium chloride salt by an ion-exchange process. Finally, the sPS-g-PMMA/MMT nanocomposite was prepared by a solution intercalation method. X-ray diffraction and transmission electron microscopy were used to confirm nanocomposite formation. It was found that the addition of only a small amount of organoclay (3 wt%) was enough to improve the thermal stabilities and properties of the nanocomposite. Polymer Journal (2011) 43, 901-908; doi:10.1038/pj.2011.79; published online 7 September 2011