非离子乳化剂细乳液聚合制备草莓型PSt/SiO2纳米复合微球

通过细乳液聚合,使用非离子乳化体系辛基酚聚氧乙烯醚(CA-897),在纳米二氧化硅水分散介质中,以1-乙烯基咪唑(1-VID)作为辅助单体制备了苯乙烯为核,纳米二氧化硅为壳的草莓型PSt/SiO2有机-无机复合微球.实验范围内得到的复合微球的平均粒径和最终SiO2含量分别介于140～180 nm和19 wt%-31wt...

PREPARATION OF PSt/SiO2 NANOCOMPOSITE MICROSPHERES THROUGH MINIEMULSION POLYMERIZATION USING NONIONIC SURFACTANT

A method was presented for the preparation of raspberry-like organic-inorganic nanocomposite microspheres with polystyrene(PSt) as cores and nano-silica particles as shells through miniemulsion polymerization in the presence of aqueous nanosilica dispersions.A small amount of nonionic CA-897(poly(oxyethylene) octyl phenylether,with 40 oxyethylene units) was used as surfactant and 1-vinylimidazole(1-VID) as auxiliary monomer.Composite microspheres were obtained via the acid-base interaction between silica particles and auxiliary monomer 1-VID.TEM indicated that the colloidally stable composite microspheres had typical raspberry-like morphology,indicating the acid-base interaction was strong enough for the formation of long-stable composite spheres.The average particle sizes and the final silica contents adsorbed on the composite microspheres could range from 140 nm to 180 nm and 19 wt% to 31 wt%,respectively,depending upon reaction conditions.The influences of some synthetic parameters,for instance,CA-897 concentration,ultrasonic frequency,ultrasonic time on the polymerization stability,diameters,silica contents and morphology of the composite microspheres were studied in detail.With the CA-897 amount increase,the average diameter of the composite microspheres tended to decrease and the silica contents adsorbed on the latexes surface increased.Ultrasonic frequency had obviously influence on the average diameter and the silica content of composite microspheres,but the effect of ultrasonic time was less.