镶嵌型乳胶粒子的合成

以苯乙烯、甲基丙烯酸甲酯、丙烯腈等单体或它们的混合物为硬单体,天然胶乳为弹性组分,经多步种子乳液聚合法制得了在天然胶乳的粒子上镶嵌硬聚合物相的互穿网络型乳胶粒子.考察了十二烷基硫酸钠、十二烷基苯磺酸钠、壬基酚聚氧乙烯醚、油酸等乳化体系,过硫酸钾、过氧化苯甲酰热引发体系及异丙苯过氧化氢-四乙烯五胺、叔丁基过氧化氢-四乙烯五胺等氧化还原引发体系对聚合反应的影响.研究了交联剂用量对互穿结合率、溶胶含量的影响及溶胀时间、硬单体组成、乳化剂种类对乳胶粒子形态的影响,确定了适宜的聚合配方和工艺条件.透射电镜观察乳粒形态结果表明,单一使用极性或非极性单体,仅得到核-壳结构乳液,而采用不同极性单体复合、溶胀、互穿,得到的是镶嵌硬聚合物型乳粒结构.

Preparation of Mosaic Latex Particles

A new kind of mosaic latex particles with gradient distribution of hard polymer have been synthesized through two-stage emulsion polymerization based on natural rubber latex. One or two or three of styrene, methyl methacrylate, acrylonitrile, isobornyl acrylate were used as hard monomer in order to prepare interpenetrating polymer network. When oleinic acid was selected as emulsifier, t-butylhydroperoxide-tetraethylene pentamine as oxi-reduction initiation system, the polymerization proceeded for 6 h in natural rubber latex smoothly with the 99% conversion of monomer. The effects of emulsifiers and the initiators on the polymerization were studied; the effects of crosslinker, swelling degree, hard monomer on morphology of the title latex particles were also investigated. The result of morphology analysis of the latex showed that the latex particle was mosaic structure with hard polymer gradient distributed.