多孔型乳胶粒子制备方法的研究

Preparation of acrylate polymer latex with hollow structure

采用半连续无皂种子乳液聚合法合成了以丙烯酸乙酯 甲基丙烯酸甲酯为核、丙烯酸乙酯 甲基丙烯酸甲酯 丙烯酸为中间过渡层、苯乙烯 丙烯酸 甲基丙烯酸为壳的三重结构的复合乳液。所得的复合乳液进行碱 /酸分步处理后 ,用透射电镜对胶粒形态进行了观察。考察了共聚乳液核壳层的玻璃化转变温度 (Tg)、交联剂、处理温度、酸处理时的初始 pH值以及溶胀剂对胶粒成孔的影响。结果表明 ,具有Tg 梯度分布的三层结构的乳胶粒子在碱 /酸处理后能得到多孔结构 ,碱 /酸处理时的温度应略高于壳层聚合物的Tg,初始的 pH值在 6 0 ,溶胀剂丁酮含量在 17% (质量分数 )时 ,得到的多孔结构的孔径较大 。

The polymer particles, which consist of the core including ethyl acrylate and methyl methacrylate, the intermediate shell including ethyl acrylate, methyl methacrylate and acrylic acid, and the outer shell including styrene, acrylic acid and methacrylic acid, were synthesized by semi continuous seeded emulsion polymerization in the absence of emulsifiers. The latex particles prepared were treated in alkali and acid solution subsequently. Particles sizes and morphologies were characterized by TEM. The influences of the crosslinking agent, treating temperature, initial pH value during acid treating and the swelling agent on the formation of hollow structure were also investigated in detail. A series of results was got after careful study, which showed that hollow particles could be observed after treatments; the formation of the particles which have different glass transition temperature( T g) distributions from shell to core is the key to form hollow particles.