Yamada Yasuyuki, Sakamoto Tatsuro, Gu Shunchao, Konno Mikio
Department of Chemical Engineering, Graduate School of Engineering, Tohoku University, Aoba, Aramaki-aza, Aoba-ku, Sendai 980-8579, Japan.
J Colloid Interface Sci. 2005 Jan 1;281(1):249-52. doi: 10.1016/j.jcis.2004.08.030.
A soap-free emulsion polymerization method with the use of an amphoteric initiator, currently proposed by the authors for producing highly monodisperse, micrometer-sized polymer particles, was examined in the polymerization of styrene with a 2,2'-azobis [N-(2-carboxyethyl)-2-2-methylpropionamidine] hydrate initiator and an NH(4)OH/NH(4)Cl pH buffer. The pH buffer was used to control the electric surface potential of particles to maintain a stable dispersion of particles and to prevent generation of new particles during the polymerization. Addition of monomer to the reaction system during polymerization could enlarge the average size of polymer particles to 5.7 microm with a coefficient of variation of 1.5%, which is much less than the standard criteria of monodispersity, 10%.
作者目前提出的一种使用两性引发剂的无皂乳液聚合法，用于生产高度单分散的微米级聚合物颗粒。该方法在苯乙烯与2,2'-偶氮双[N-(2-羧乙基)-2-甲基丙脒]水合物引发剂以及NH(4)OH/NH(4)Cl pH缓冲剂的聚合反应中进行了研究。pH缓冲剂用于控制颗粒的表面电势，以保持颗粒的稳定分散，并防止聚合过程中产生新的颗粒。在聚合过程中向反应体系中添加单体，可以将聚合物颗粒的平均尺寸扩大到5.7微米，变异系数为1.5%，远低于单分散性的标准标准10%。
