环硅氧烷阳离子型乳液聚合中的单体迁移  

Monomer Migration of Octamethylcyclotetrasiloxane in Canionic Emulsion Polymerization

作　　者：周安安[1] 郑水燕[1] 张立庆[1] 杨志祥[1] 

机构地区：[1]浙江科技学院生物与化学工程学院,杭州310012

出　　处：《有机硅材料》2009年第2期81-85,共5页Silicone Material

基　　金：浙江省自然科学基金项目(Y406306)

摘　　要：以八甲基环四硅氧烷(D4)为单体,十二烷基二甲基苄基溴化铵(DBDA)为阳离子乳化剂,KOH为催化剂,进行环硅氧烷阳离子型乳液聚合单体迁移的研究。结果表明,乳胶粒界面为聚合场所,聚合初期,由于比表面积的不同,单体液滴形成的乳胶粒与胶束形成的乳胶粒之间形成单体浓度差,导致单体发生迁移,直至平衡。在此基础上,还考察了温度、搅拌强度及DBDA用量对迁移速率的影响。结果表明,乳胶粒界面为聚合场所,在聚合初期,单体液滴形成的乳胶粒与胶束形成的乳胶粒之间在聚合过程中形成单体浓度差异,导致单体在该两类乳胶粒之间发生迁移,迁移使得聚合过程中乳胶粒之间单体浓度差逐渐缩小并达到相同的平衡值,而聚合体系中油层体积也随之减少至恒定值。温度、搅拌速度及DBDA用量增加,单体扩散速度均加快,导致聚合过程中油层体积的减少速度增加,两层单体浓度差下降。The study on the monomer migration for canionic polymerization of cyclosiloxane in aqueous emulsion was perfected with octamethylcyclotetrasiloxane （D4） as monomer, KOH as catalyst and benzyldimethyldodecylammonium bromize （DBDA） as canionic emulsifying agent. The results showed that the polymerization occurred at the latex particles interface is. In the early polymerization stage, monomers migrated between latex partieles formed by monomer drops and micelles due to the the differenee of specific surfaee area and monomer concentrations. During the polymerization, the monomer coneentration differences between the particles decreased, while the volume of the particles decreased as well. , The migration continued until equilibrium was achieved. The effects of temperature, stirring intensity and the DBDA concentration on the rate of migration were investigated in details. When temperature, stirring speed and DBDA content increased, the proliferation rate of monomer was aceelerated, resulting in oil volume reduetion inerease while two - layer monomer concentration difference decline.

关 键 词：环硅氧烷 阳离子型乳液聚合 单体迁移 

分 类 号：TQ316.334[化学工程—高聚物工业]