| Silica (SiO2) particle filled polymer can effectively improve strength，modulus andthermostability of the matrix. However, application of nano-SiO2is limited because itaggregates easily and disperses unevenly in polymer matrix due to the tremendousdifference structure between rigid particles and the polymer matrix as well as their poorcompatibility.Nano-SiO2with functional vinyl groups was firstly in-situ synthesized throughsol-gel method in the styrene/butyle acrylate (St/BA) dispersing media. The nano-SiO2/styrene-acrylic composite emulsion was prepared by the semi-continuous seed emulsionpolymerization in the presence of silane-modified SiO2/St/BA dispersion. Composition,morphology, microsphere size, and size distribution of composite emulsion can beeffectively controlled by adjusting the kinds and dosages of monomers, precursor anddispersant. The effects of preparation technology and nano-SiO2content on structure,thermal stability, rheological behaviors, and solvent resistance of the composite emulsionwere studied.The results showed that the kinds of monomers influence the morphology of SiO2.The nano-SiO2particle went small with increasing the content of dispersion medium. Inother words, a uniform distribution and stable dispersion of nano-SiO2/organic monomercould be obtained by the sol-gel process. The1H-NMR spectra verified the mechanism ofnucleation of polymer composite emulsion. The results of dynamic laser particle sizeanalysis（DLS）and transmission electron microscopy (TEM) showed that the compositeemulsion with a latex particle size of around90nm~100nm. The thermal gravimetricanalysis（TGA） data indicated that thermal stability of the composite emusion wasimproved with high nano-SiO2content. The composite emusion exhibited obviousshear-thinning behavior in high SiO2content. And the addition of silica could facilitate solvent resistance of styrene-acrylic polymer emulsion. |
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