阴离子分散聚合制备单分散聚合物微球的研究.docVIP

单位代码：10010 学 号：2001000513 北京化工大学 硕士研究生学位论文 题 目：阴离子分散聚合制备单 分散聚合物微球的研究 专 业：材 料 学 研 究 生：徐 人 威 指导老师：徐 自 力 日 期：2004年3月1日 阴离子分散聚合制备单分散聚合物微球的研究 摘 要 以苯乙烯为单体、聚乙烯基吡咯烷酮为分散剂、偶氮二异丁腈为引发剂、醇/水混合物为分散介质进行了自由基分散聚合，考察了单体浓度、分散剂浓度、引发剂浓度、分散介质组成等因素对聚合物微球粒径和粒径分布的影响，较好的：单体30(g/100g溶液)，分散剂3.0(g/100g溶液)，引发剂0.5(g/100g单体)，无水乙醇90(g/100g介质)，聚合温度为68℃SPHERES BY ANIONIC DISPERSION POLYMERIZATYION ABSTRACT The radical dispersion polymerization of styrene in ethanol/water medium in the presence of polyvinylpyrrolidone using azobisisobutyr -onitrile as initiator was carried out. The effects of stabilizer concen -tration, monomer concentration, initiator concentration and medium composition on the size and size distribution of polymer particles were investigated. the better reaction match is, monomer concentration 30(g/100g solution), stabilizer concentration 3.0(g/100g solution), initiator concentration 0.5(g/100g monomer)，90(g/100g me -dium)，68℃。On the basis of the preceding work, the anionic dispersion polymerization of styrene in n-Hexane medium in the presence of steric stabilizer SEBS using n-butyllithium as initiator was mainly carried out. It was showed by experiments that the main factors of anionic dispersion polymerization, such as steric stabilizer concentration, initiator concentration, monomer concentration, the method of adding monomer, monomer multi-addition and promoter etc, influenced the particle size and size distribution, Some factors,such as monomer concentration and steric stabilizer concentration, influence the time for the onset nucleation. And through the study of the mechanism of particle formation and stabilization, it was proved that the mechanism of adsorbentstabilization is dominant during anionic dispersion polymerization and the mechanism of nucleation is the aggregation of living-polymers. The results indicate that anionic dispersion polymerization is considered living polymerization, the p