以聚四氟乙烯乳胶粒子为种子的丙烯腈／苯乙烯乳液共聚合

Styrene-Acrylonitrile Emulsion Copolymerization in the Presence of Polytetrafluoroethylene Seeds

以工业聚四氟乙烯(PTFE)乳胶粒子为种子,进行苯乙烯/丙烯腈(St/AN)种子乳液聚合,研究了单体加入方式、OP-10和十二烷基硫酸钠(SDS)复合乳化剂组成和用量对聚合稳定性、复合乳胶粒子平均粒径及粒径分布和形态的影响。结果表明,单体预乳化半连续乳液聚合稳定性高于间歇乳液聚合,两者又高于单体未乳化半连续乳液聚合;当OP-10/SDS复合乳化剂(OP-10/SDS质量比为2～1/2)用量小于4%质量分率时,采用间歇和半连续乳液聚合得到的复合乳胶粒子的平均粒径均大于PTFE种子;当复合乳化剂用量大于4%质量分率时,复合乳胶粒子平均粒径小于PTFE种子,与St/AN共聚物(SAN)二次粒子形成有关。PTFE粒子呈棒状或鹅卵状,而种子间歇乳液聚合和单体预乳化半连续乳液聚合得到的PTFE-SAN复合粒子均呈球状,PTFE被SAN包覆较完全。

Styrene （St） and acrylonitrile （AN） emulsion copolymerization in the presence of commercialpolytetrafluoroethylene latex particles as the seeds were carried out, and influence of monomers adding policy, the composition and dosage of OP-10/sodium dodecylsulfate （SDS） composite emulsifier on the polymerization stability, average size and size distribution, and morphology of composite latex particles were investigated. It was found that the polymerizationstability of seml-continuous emulsion copolymerization added with pre-emulsified monomers was better than that of batch emulsion copolymerization and semi-continuous emulsion copolymerization added with pure monomers. The mean size of PTFE-St/AN copolymer （SAN） composite latex particles was greater than that of PTFE seeds when the total dosage of OP-10 and SDS was lower than 4.0% mass fraction （based on monomers） and mass ratio of OP-10 to SDS in range of 1/2 to 2. When the total dosage of OP-10 and SDS was greater than 4.0%, the mean size of PTFE-SAN latex was lower than that of PTFE seeds due to the secondary particle formation of SAN. PTFE-SAN composite particles exhibited spherical shape with PTFE coated by SAN, while PTFE seeds exhibited rod or egg-like shape.