writer：Fa-Ai Zhang, Dong-Keun Lee, Thomas J. Pinnavaia
keywords：mesoporous silica nanocomposites,emulsion polymerization
source：期刊
specific source：polymer
Issue time：2009年

PMMA - mesoporous silica nanocomposites were prepared for the first time through in-situ batch emulsion polymerization of methyl methacrylate in the presence of large pore MSU-F silica with a mesocellular foam structure (24.8 nm average cavity size) and subsequent compression molding of the polymer-silica nanoparticle mixtures.  For composites containing 5.0 wt % silica, the onset decomposition temperature and the temperature at 10% weight loss for the nanocomposite increased 41 ^oC and 50 ^oC, respectively, in comparison to pure PMMA.  The glass transition temperature of the nanocomposite increased 9.3 ^oC, as determined by differential scanning calorimetry.  In addition, the storage modulus determined by dynamic mechanical analysis increased 17 % and 80% at 50 ^oC and 100 ^oC, respectively.  Substantial improvements in tensile strength (+50 %) and modulus (+72 %), were achieve at 10 wt % nanoparticle loading.    Composites made by compression molding of physical mixtures of PMMA and MSU-F silica powders provide less improvement in thermal stability, glass transition temperature and mechanical properties in comparison to the composites made through in-situ batch emulsion polymerization.  Unlike previously reported composites made from nanoclays, the silica composites reported here show improvements in both thermal stability and mechanical reinforcement.