核壳型高交联聚硅氧烷/丙烯酸酯复合乳液粒径分布

以苯基三乙氧基硅烷、八甲基环四硅氧烷、γ-甲基丙烯酰氧基丙基三甲氧基硅烷为单体合成了高交联聚硅氧烷乳液,然后与丙烯酸丁酯(BA)、甲基丙烯酸甲酯(MMA)接枝共聚,得到具有核壳结构的高交联聚硅氧烷/BA/MMA 复合乳液。考察了乳化剂的种类与用量、单体加料方式、单体总浓度对乳胶粒粒径分布的影响。实验结果表明,采用辛基苯酚聚氰乙烯醚/十二烷基苯磺酸复合乳化剂合成聚硅氧烷乳液,BA 和 MMA 加入前补加十二烷基苯磺酸钠乳化剂且两单体以半连续法加入,可得到较均匀的复合乳液。当复合乳化剂用量为硅烷单体质量的10%、十二烷基苯磺酸钠补加量为 BA 和 MMA 总质量的1.5%、单体总量为体系中水质量的35%时,乳胶粒的体积平均直径约为71 nm。

Particle Diameter Distribution of Highly Cross-Linked Polysiloxane/Acrylate Composite Latexes with Core-Shell Structure

Polysiloxane/acrylate composite latexes with core of highly cross-linked polysiloxane and shell of polyacrylate was prepared via emulsion polymerization of core monomers phenyltriethoxysilane, octamethylcyclotetrasiloxane and γ-methacryloxypropyltrimethoxysilane,and followed by grafting of shell monomers n-butyl acrylate(BA)and methyl methacrylate(MMA).Emulsifier type and dosage, monomer feeding mode and total monomer concentration influence particle diameter distribution of the latexes.Even latex particles with core-shell structure were obtained by using dodecyl benzene sulfonic acid and octylphenol polyoxyethylene ether composite emulsifiers in core emulsion polymerization and sodium dodecylbenzene sulfonate(SDBS)emulsifier in successive shell grafting-copolymerization. Semi-batch polymerization achieved effective control for core-shell structured composite latexes with narrow particle diameter distribution.When composite emulsifiers added are 10% of silane mass, SDBS is 1.5% of BA plus MMA total mass and amounts of all monomers are 35% of water mass, composite latexes with 71 nm volumetric average diameter can be obtained.