羟基聚硅氧烷阳离子型乳液缩聚过程及分子量模型  

The Course and Molecular Weight Model for Cationic Emulsion Condensation Polymerization of Polydimethylsiloxanols

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,浙江杭州310023

出　　处：《高校化学工程学报》2010年第3期537-541,共5页Journal of Chemical Engineering of Chinese Universities

基　　金：浙江省自然科学基金项目(Y406306)

摘　　要：以羟基聚硅氧烷齐聚物为单体,十二烷基二甲基苄基氢氧化铵(BDAH)为乳化剂兼催化剂,进行阳离子型乳液缩聚过程及动力学模型研究。研究结果表明:聚合过程中,体系界面张力及乳胶粒粒径保持恒定,单体不发生迁移,缩聚在单体液滴形成的乳胶粒界面上进行;在此基础上,推导了缩聚分子量模型:4ρkFt/ME=ln[(ME+M)/(ME-M)],lnME=-ΔH/RT+C,结合实验数据,获得kF阿累尼乌斯公式:kF=1.83×105e-27718/T,及缩聚反应焓:ΔH=10.8kJ·mol-1。The reaction course and kinetics model of cationic emulsion condensation polymerization were investigated by using the polydimethylsiloxanols （PDMS） as monomer and benzyldimethyldodecyl-ammonium hydroxide （DBAH） as cationic emulsifying agent and catalyst. The polymerization was carried out in a glass reactor with mechanical stirring, and during the course of reaction, a certain amount of reactant was taken out sever times to measure the molecular weight of the synthesizing polymer （by GPC）, the particle size of emulsion and the surface tension of the system. It was found that the particle size and the surface tension at the air-water interface keep essentially unchanged during the whole course of the polymerization reaction. It indicates that the monomers do not undergo a migration in the aqueous phases to form new particles, and the condensation polymerization is performed only on the oil-water interface of particles formed by monomer liquid drops. Based on above understanding, the molecular weight model of the condensation polymerization products was derived; combining with the experimental data of molecular weight, the constants of Arrhenius formula kF in the molecular weight model at various temperatures were obtained. Moreover, according to van’t Hoff equation, the enthalpy of condensation polymerization reaction ΔH was calculated too.

关 键 词：羟基聚硅氧烷 阳离子型乳液缩聚 分子量模型 模型参数 

分 类 号：O631.5[理学—高分子化学] O648.23[理学—化学]