摘要
在微波辐照下 ,以过硫酸钾 (KPS)为引发剂 ,丙酮水溶液 (质量比 1∶1)为分散介质 ,进行了苯乙烯 (ST)和其它共聚单体 :甲基丙烯酸甲酯 (MMA)、甲基丙烯酸丁酯 (BMA)、丙烯酸乙酯 (EA)及顺丁烯二酸酐 (BDA)的无皂乳液聚合 ,得到了稳定的纳米胶乳粒子。讨论了共聚单体的种类和浓度对粒子水化半径的影响。增加配方中亲水性单体含量 ,使引发反应中引发剂的消耗量增加 ,粒子表面电荷密度增大 ,同时亲水性增加 ,油水界面张力减小 ,粒子变得稳定 ,有利于小粒子的生成。粒子的大小随亲水性单体的含量呈曲线关系 。
Using acetone-water as medium and potassium persulfate(KPS) as initiator, emulsifier-free emulsion co-polymerization of styrene with co-monomers: methyl methacrylate(MMA), butyl methacrylate(BMA), ethyl acrylate(EA) and maleic anhydride(BDA) under microwave irradiation have been investigated. The influence of each co-monomer′s content and hydrophilicity on the hydrodynamic radius < R h > of the synthesized copolymer nanoparticles was discussed in detail. The results show that the increase in ratio of hydrophilic copolymer causes an increase in consumption of initiator in the initiation reaction, so an increase in the concentration of the surface -SO 3 - groups and the stability of the latex, which gives rise to the formation of smaller micelles. The nano-particle′s radius will increase again when the co-monomer′s content increase to a certain degree. The curve of the particle hydrodynamic radius vs. the co-monomer′s content has a minimum point. It can also be found that the size of the particle will be smaller when the solubility of the co-monomer is larger. But the ionic co-monomer has little effect on the stability of the latex though it also could cause the particle′s radius decrease. So nano-particles with a narrow size distribution could be obtained under microwave irradition through emulsifier-free emulsion polymerization in acetone-water medium.
基金
国家自然科学基金资助项目 (2 97730 0 1)&&
