大粒径PBA/PMMA核壳型乳胶粒的合成、表征及其改性PVC

Synthesis charactieristic of large PBA/PMMA latex particles and the modification for PVC

采用向种子乳液中连续滴加预乳液的方法制备了大粒径(约1μm)核壳型PBA/PMMA乳胶粒,经透射电镜和光散射粒径分析仪测试乳胶粒子的微观结构和粒径分布,结果显示乳胶粒的微观形貌确实为核壳结构,粒径接近微米级,粒径呈高斯分布并且相对分布较窄.将此类乳胶粒干燥后用于PVC改性,考察了粒径对共混物力学性能的影响,其中粒径在500 nm左右时的ACR具有较好的增韧效果.

Latex particles of up to 1μm can be made by standard emulsion polymerization methods.In this work,it is shown that use of an oil-soluble initiator AIBN) provides a means by which large(1?μm) polybutyl acrylate/polymethyl methacrylate latex particles can be made by squential core-shell polymerizations.It is suggested that the limited water solubility of AIBN decreases the formation of secondary particles and that the lower ionic strength of the water phase enhances stability of the latex compared to a conventional persulfate initiator.To further minimize formation of secondary particles,long reaction times and progressively larger proportions of seed latex are used in successive reactions.Transmission electron microscope(TEM) study indicates that ACR latex particles have a regular core-shell structure obviously.The exact particle size distributions were determined with a particle size analyzer and are shown to be Gaussian about means and relative narrow distribution.The ACR were used as the modifier for PVC.The results showed that the impact strength of the modified PVC with ACR particle of 0.5?μm were better than that of others.