含羧基苯/丙乳液乳胶粒径及其碱增稠特性

Particle Size and Alkali-Thickening Characteristics of Styrene/Acrylate Emulsion Containing Carboxyl Groups

以苯乙烯(St)、甲基丙烯酸或丙烯酸(MAA或AA)、丙烯酸丁酯(BA)和甲基丙烯酸甲酯(MMA)为共聚单体,采用种子乳液聚合半连续工艺合成苯/丙乳液.讨论了乳液聚合过程中氨化反应温度、AA和MAA加入方式及用量对共聚物乳液粘度、乳胶粒径大小及羧基分布的影响,并简要分析了其碱增稠机理.实验结果表明:氨化反应温度为60℃时,有较好的碱增稠效果,并可适度减小乳胶粒子的粒径;不同的AA、MAA加入方式及时间会使羧基在乳胶粒中的分布不同,所带来的碱增稠效果也不同;同时,以特定的聚合工艺可引起苯/丙乳液粒子表面羧基的富集.

Styrene/acrylate emulsion was synthesized by the semi-continuous technique of seeded emulsion polymerization, with styrene （St）, methacrylic acid （MAA） or acrylic acid （AA）, butylacrylate （BA） and methylmethacrylate （MMA） as copolymerization monomers. The effects of the aminating temperature, the adding manners and the contents of AA and MAA on the viscosity, the particle size and the carboxyl distribution of the emulsion were then discussed. Moreover, the alkali-thickening mechanism of the emulsion was briefly analyzed. Experimental results show that： （1） at an aminating temperature of 60℃, preferable alkali-thickening effect is obtained, and the panicle size is reasonably reduced; （2） different adding manners and adding time of AA and MAA may result in different distributions of carboxyl groups in the emulsion panicle as well as different alkali-thickening properties; and （3） the enrichment of carboxyl groups on the surface of emulsion particles can be achieved by a specific polymerization technique.