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以辛基酚聚氧乙烯醚(OP-10)和OP-4、十六烷基三甲基溴化铵(CRAB)为复合乳化剂,正戊醇为助乳化剂,含氢聚二甲基硅氧烷(H-PDMS)、甲基丙烯酸甲酯(MMA)、丙烯酸正丁酯为聚合单体,以水溶性过硫酸铵(APS)-亚硫酸氢钠(NaHSO3)为氧化还原引发剂,采用微乳液聚合方法,制备了4种引发剂浓度不同的聚合物微乳液,研究了引发剂浓度对MMA/n-BA/H-PDMS的微乳液共聚合的影响.通过FT-IR和1H-NMR分析证明,微乳液体系中的聚合物含有氢聚硅氧烷/丙烯酸酯共聚物;实验表明,当引发剂浓度太低时,聚合体系存在引发诱导效应;而当引发剂浓度适当提高时,聚合过程存在明显的恒速期;但当引发剂浓度较高时,聚合过程无明显恒速期,继续提高引发剂浓度,聚合速率明显变大,其聚合速率的最大值也更高.通过动力学研究,分别得到了聚合速率与产物特性黏度的动力学关系式:Rp∝ [APS]0.75,[η] ∝ [APS]-0.07.另外,实验结果表明,随着聚合转化率的提高,乳胶粒径增大.在这些研究基础上初步探讨了微乳液聚合机理.

The effects of the initiator concentration on the copolymerization of H-PDMS/MMA/n-BA microemulsion were investigated,by preparation of microemulsions with different initiator concentration by microemulsion polymerization,in which OP-10,OP-4 and cetyltrimethylammonium bromide (CTAB) as emulsifier mixture,n-pentanol as co-emulsifier,methyl methacrylate (MMA),n-butyl acrylate (n-BA) and hydrogencontained polymethylsiloxane (H-PDMS) as mixed monomers,(NH4)2S2O8 (APS)-NaHSO3 as redox initiator.The spectra of FT-IR and 1H-NMR indicate that H-PDMS/acrylate copolymer is prepared.The results show that the initiator inductive effect appears in the microemulsions when the initiator concentration is low,and a distinct constant rate occurs in the polymerization when the initiator concentration increases,but when the initiator concentration increases furthermore the reaction rate of polymerization commences to accelerate,and higher the initiator concentration is,more quick the reaction rate of polymerization is,and also higher the initiator concentration is,bigger the maximum reaction rate of polymerization is.Through dynamic analysis,the relations between the reaction rate of polymerization and intrinsic viscosity of the obtained emulsions were determined,which could be expressed as Rp∝[APS]0.75,[η]∝[APS]-0.07 respectively.The experiments also exhibit that the particle size of microlatex augments as the reaction rate of polymerization increases.