Abstract: The styrene-acrylic emulsion was prepared by semi-continuous seed-emulsie polymerization with monomers of methyl methacrylate(MMA), butyl acrylate(BA)and styrene(St)as co-monomers. The influence of the preparation process, the initiator type, the concentration of emulsifier. the concentratio of emulsifier of seed emulsion the dropping rate of pre-emulsion and initiator on the latex particle size and its distribution (PSD) were investigated. The experimental results showed that dropwise addition of pre-emulsion could get the smallest particle size; the initiator type had no effect on the particle size; the particle size of emulsion reached 96 nm with the narrowest size distribution when the concentrate of emulsifier was 10%; at the same concentration of the emulsifier in pre-emulsification process, the particle size of emulsion was 104 nm when the concentrate of the seed emulsion was 40%; the par ticle size did not change when the dropping rate of pre-emulsion was lower than 163 mg/s and the dropping rate of initiator was lower than 11. 5 mg/s. TEM analysis revealed the nucleation growth mechanism of the latex particles during the emulsion polymerization process, resulting in an optimum resolution for particle morphology control.

Key words: styrene-acrylic emulsion, particle size and its distribution, emulsifier

摘要： 以甲基丙烯酸甲酯(MMA)、丙烯酸丁酯(BA)和苯乙烯(St)为单体,采用半连续种子乳液聚合工艺,制备了苯丙聚合物乳液,研究了乳液聚合过程中的制备工艺、引发剂类型、乳化剂用量、种子乳液的乳化剂用量、预乳液和引发剂的滴加速率对不同阶段的乳胶粒粒径及其分布的影响。结果表明:半连续种子乳液聚合,单体滴加工艺制备的乳液粒径最小;引发剂种类对粒径无影响;乳化剂用量为10%时,乳液的粒径为96 nm,且分布宽度最窄,在种子乳液中乳化剂用量为40%时,乳液粒径最小,为104 nm;当预乳液滴加速度小于163 mg/s,引发剂滴加速率小于11.5 mg/s时,粒径未有变化。TEM测试表明了乳胶粒在整个乳液聚合过程中的成核长大的机理,并得到乳胶粒形貌可控的最佳方案。

关键词: 苯丙乳液, 粒径及其分布, 乳化剂