乳化剂对核壳乳液聚合体系的影响

本文采用半连续-预乳化工艺制备了表层羧酸化的聚丙烯酸丁酯／聚（甲基丙烯酸甲酯-衣康酸）（PBA／P（MMA—ITA））核壳乳液。通过对乳液粒径及其分布、凝聚率和表面张力的分析研究了乳化剂种类、配比、用量以及功能单体等因素对聚合体系稳定性的影响，采用非水滴定法、傅立叶红外光谱仪（FTIR）、差示扫描量热仪（DSC）、透射电子显微镜（TEM）等方法对乳胶粒子进行了表征。实验结果表明：OP—10引入乳化体系，使聚合体系的稳定性增加，但随着OP—10用量的增加，乳胶粒子粒径增大、粒径分布变宽，聚合体系的稳定性降低；复合乳化剂SDS／OP—10用量增加，乳胶粒子粒径减小，聚合体系的稳定性增加；极性单体ITA的使用导致聚合体系的稳定性降低。分析结果还证明ITA已成功参与了壳层的聚合反应，乳胶粒子具有明冠的核/壳结构。

Effects of Emulsifier on the Core/shell Emulsion Polymerization System

The surface carboxylated PBA/P（MMA-ITA） latex with core/shell structure was prepared by semi-continuous pre-emulsion method. The effects of composite emulsifier and function monomer on the emulsion stability were measured from particle size and its distribution, surface tension and the coagulation. The samples were characterized by the methods of nonaqueous acid-base titration, Fourier Transform Infrared Spectrophotometer （FTIR）, Differential Scanning Calorimetry （DSC） and Transmission Electron Microscope（TEM）. The results showed that particle size decreased and emulsion stability increased with the increasing dosage of emulsifier. With the increasing content of OP-10, the particle size increased and its distribution became wider and the emulsion stability decreased. Due to the introduction of ITA the emulsion stability decreased and Tg increased. ITA has copolymerized with MMA monomer successfully. TEM photos indicated that latex particles were constructed with a mode of core/shell structure.