D_4的微乳液聚合

Microemulsion polymerization of D_4

以八甲基环四硅氧烷(D4)为原料,在十二烷基苯磺酸(DBSA)催化下进行微乳液聚合反应,制得有机硅乳液。讨论了催化剂用量、乳化剂用量、加料方式、单体滴加速度对微乳液粒径及粒径分布的影响。结果表明在一定范围内,随着催化剂、乳化剂用量的加大,乳胶粒粒径变小,粒径分布变宽;当催化剂DBSA用量为微乳液质量的3%、乳化剂OP用量为微乳液质量的2%、DBSA与乳化剂的质量比为3∶2、单体滴加时间为0.5h时,聚二甲基硅氧烷的摩尔质量最大;与一次加料法相比,采用单体滴加法时乳胶粒的粒径更小,粒径分布更窄;单体滴加时间越长,乳胶粒的粒径越小,粒径分布越宽。

The silicone emulsion was prepared by microemulsion polymerization with D_4 under the catalysis of octamethylcyclotetrasiloxane. The content of catalyzer, emulsifier and monomer dropping rate on the particle size and size distribution of microemulsion was discussed. The result showed that in some extent, as the increasing content of catalyzer and emulsifier, the particle size of latex became small, while its size distribution became wide. When the content of catalyzer was 2 % of the mass of latex, the mol mass of polydimethyl siloxane was maximum. Compared with one time addition, the particle size of latex by monomer dropping was narrow; as the monomer dropping time was longer, the grainsize was smaller, and the size distribution was wider.