高SiO2含量硅溶胶/聚丙烯酸酯复合乳液的制备

用硅溶胶、丙烯酸酯类单体，以过硫酸钾为引发剂，配以适当的乳化剂，采用乳液聚合法制成了高SiO₂含量硅溶胶-聚丙烯酸酯复合乳液。系统的研究了温度、乳化剂种类及用量、单体SiO₂质量比等因素对乳液稳定性的影响。结果表明：75℃为最佳反应温度；十二烷基硫酸钠(SDS)为最佳乳化剂；当SDS质量分数为0.45%～0.7%、单体SiO₂质量比为3时，可制得SiO₂质量分数为10%的复合乳液，且乳液的稳定性达到使用要求，此法制得的复合乳液的涂膜水白性较共混改性乳液（硅溶胶和纯丙乳液）和纯丙乳液的涂膜有显著的提高；TEM图片显示，复合乳液中，硅溶胶粒子是以纳米SiO₂粒子存在的，且在复合乳液中比在共混改性乳液（硅溶胶和纯丙乳液）中分散的更均匀。

Preparation of compound emulsion of high SiO2 sol/polyacrylate

The compound emulsion of SiO₂ sol/polyacrylate was synthesized by in site emulsion polymerization using SiO₂ sol and acrylate monomer. Some factors affecting the stability of the compound emulsion were discussed. It shows that the better reaction temperature is 75℃ and the anionic sodium dodecyl sulfate(SDS) was the more effective emulsifier. When SDS was between 0.45%～0.7% and the weight ratio of the monomer to SiO₂ is 3, the compound emulsion of high SiO₂ sol/acrylic resin with 10% of SiO₂ was synthesized and its stability is good for use. The transmission electron micrographs (TEM) of the compound emulsion shows that the silica particles in the compound emulsion are dispersed more homogeneously than that in the blend emulsion of polyacrylate emulsion and silica-sol. The films of the compound emulsion show an excellent waterproof compared with those of the pure polyacrylate emulsion and the blend of polyacrylate emulsion and silica-sol.