Abstract: In this contribution,polyvinyl acetate(PVAc)based composite emulsion was successfully prepared by semi-continuous seeded emulsion polymerization,whose average particle size was about 115nm. The novel compound surfactants and the particle size control monomer BA were systematically investigated as the vital factors for controlling the particle size of the latex,because of BA's inhibitory action on the free radical polymerization of vinyl acetate monomer. Based on the results of chemical structure analysis,particle size distribution,morphology and thermal properties,it can be found that the average particle size of PVAc composite emulsion can be effectively decreased when the anionic surfactants PCA078 and PCA507 is used,but the average particle size began to increase when the BA content reached a certain proportion. A certain amount of BA monomer can inhibit the growth of PVAc molecular chains and increase the number of particles by secondary nucleation,which can effectively decrease the latex's particle size in the emulsion system. However,when BA was excessive,the self-polymerization of BA was significantly increased,which can't reduce the particle size.

Key words: polyvinyl acetate(PVAc), emulsions, surfactants, particle size control monomer, butyl acrylate, nucleation

摘要： 采用半连续种子乳液聚合，成功制备出平均粒径大小为115nm的小粒径聚乙酸乙烯酯（PVAc）基复合乳液。系统考察了新型复配表面活性剂以及丙烯酸丁酯（BA）作为粒径调控单体对PVAc乳液乳胶粒粒径的影响。通过对复合乳液的化学结构、粒径分布、形貌以及热力学性能的分析，实验结果表明，采用阴离子型的PCA507和PCA078复配表面活性剂能够有效地降低PVAc乳液的平均粒径；一定含量的BA能够抑制PVAc分子链的生长，并能以新生二次成核的方式扩充体系粒子数，从而达到减小体系整体乳胶粒粒径的目的，而BA过量时，其自聚成核较为明显，不能有效地降低体系复合乳胶粒的粒径，故而出现乳胶粒的粒径随BA含量的增加呈规律性的变化。

关键词: 聚乙酸乙烯酯, 乳液, 表面活性剂, 粒径调控单体, 丙烯酸丁酯, 成核