Synthesis and properties of silicone/montmorillonite nanocomposites by in-situ intercalative polymerization

Using cetyltrimethylammonium bromide (CTAB) as organic treatment agent, phenylmethylsilicone/organic montmorillonite (OMMT) nanocomposites were prepared by in-situ intercalative polymerization. The internal structure and morphology of the nanocomposites were characterized by X-ray diffraction (XRD), scanning electron microscope (SEM) and transmission electron microscope (TEM). Mechanical properties, high temperature resistance and barrier performance for gas and water were also studied. The results show that molecules of silicone chains insert into the layer of montmorillonite (MMT), and the interlayer distance of MMT is expanded effectively after polymerization of phenylmethylsilicone prepolymer and methyl methacrylate, even forming exfoliated nanocomposites. The silicone/OMMT nanocomposite containing 8 wt% OMMT has better high temperature resistance and barrier properties with low thermal weight loss of 25% at 750 °C. The nanocomposite, containing 6 wt% OMMT, has better mechanical performance with tension strength of 6.264 MPa, which is five times more than that of pure silicone. When the nanocomposite contains 4 wt% OMMT, the compression strength is 11.503 MPa, which is four times bigger than that of pure silicone.