【摘要】 以十二烷基苯磺酸钠(SDBS)为乳化剂、硫酸为催化剂,将八甲基环四硅氧烷(D4)与四甲基四乙烯基环四硅氧烷(D4Vi)进行正离子开环共聚,制备了聚硅氧烷乳液。比较了超声预乳化方式和机械搅拌预乳化方式对预乳液粒径分布、乳液粒径分布及聚合反应动力学的影响,考察了单体质量比、聚合温度、催化剂浓度和乳化剂浓度对聚合动力学及乳液粒径分布的影响。结果表明,超声预乳化聚合中同时存在单体小液滴成核和胶束成核2种机理,超声预乳液稳定性较好,平均粒径为180nm,最终转化率可达90%左右;当聚合温度为80℃、SDBS质量分数为1%、硫酸质量分数为3%时,可以制得稳定的聚硅氧烷乳液。更多还原

【Abstract】 The polysiloxane emulsion of octamethyl cyclotetrasiloxane and tetravinyl tetramethyl cyclotetrasiloxane was prepared using sodium dodecyl benzene sulfonate as an emulsifier and sulfuric acid as catalyst.The effects of ultrasonic and strring emulsification method on the monomer drops diameter,copolymerization and latex particles diameter were compared. The effects of the monomer ratio,temperature,catalyst and emulsifier concentration on the conversation and latex particles diameter were also studied.The results showed that two kinds of nucleation mechanism, monomer drop nucleation and micelle nucleation, existed in the copolymerization emulsified by ultrasonic method.Compared with stirring emulsification,by ultrasonic method the stability of latex emulsified was stronger,its mean diameter was 180 nm,and the conversion was higher.Stable polysiloxane emulsion were obtained with the polymerization temperature of 80 ℃,catalyst concentration of 1%and emulsifier concentration of 3%.更多还原