Surface modification of montmorillonite with novel modifier and preparation of polystyrene/montmorillonite nanocomposite by in situ radical polymerization

Exfoliated polystyrene/organo-modified montmorillonite nanocomposite was synthesized through in situ free radical polymerization by dispersing a modified reactive organophilic montmorillonite layered silicate in styrene monomers. The original montmorillonite (MMT) was modified by a novel cationic surfactant. A cationic initiator, consisting of a quaternary ammonium salt moiety, α-phenyl chloro acetyl chloride moiety, and 9-decen-1-ol moiety, was intercalated into the interlayer spacing of the layered silicate. Modified MMT clays were then dispersed in styrene monomers and subsequently polymerized by a free-radical in situ polymerization reaction to yield polystyrene/montmorillonite nanocomposite. The structure of obtained modifier was investigated by proton nuclear magnetic resonance (¹H NMR) and Fourier-transform infrared (FT-IR) spectroscopy. The exfoliating structure of nanocomposite was probed by X-ray diffraction (XRD) and transmission electron microscopy (TEM). Comparing with pure polystyrene, the nanocomposite showed much higher decomposition temperature and higher glass transition temperature (T_g).