化工学报 ›› 2008, Vol. 59 ›› Issue (8): 2149-2155.

• 材料化学工程与纳米技术 • 上一篇    

苯乙烯的间歇-半连续RAFT细乳液聚合

杨雷;罗英武;李伯耿   

  1. 浙江理工大学先进纺织材料与制备技术教育部重点实验室,材料与纺织学院,浙江 杭州 310018;化学工程国家重点实验室,浙江大学化学工程与生物工程学系,浙江 杭州 310027
  • 出版日期:2008-08-05 发布日期:2008-08-05

Batch-semi-batch two-stage RAFT mini-emulsion polymerization of styrene

YANG Lei;LUO Yingwu;LI Bogeng   

  • Online:2008-08-05 Published:2008-08-05

摘要:

进行了苯乙烯的间歇-半连续RAFT细乳液聚合,考察了半连续段的起点、单体滴加速率及最终胶乳固含量的影响。结果发现:从最终胶乳的稳定性考虑,半连续聚合的起点选择在间歇聚合的高转化率时期更好;若综合考虑胶乳的稳定性、分子量及其分布、固含量、乳化剂及共稳定剂在胶乳中的残留率等因素,半连续聚合的起点可适当提前,但必须在间歇聚合成核期结束后。过早容易引起乳液的失稳;过迟会延长反应时间,降低聚合物的制备效率,导致死聚物链含量升高。聚合体系的稳定性与胶乳的固含量密切相关,最终固含量不宜超过40%。采用间歇-半连续二段聚合工艺可以制得窄分子量分布(PDI=~1.3),低乳化剂及共稳定剂残留量(~1.5%,质量)的高分子量聚合物(≈8×104g•mol-1)。

关键词: 活性自由基聚合, RAFT聚合, 细乳液聚合, 半连续聚合

Abstract:

A batch-semi-batch two-stage reversible addition-fragmentation chain transfer(RAFT) mini-emulsion polymerization of styrene was investigated.It was found that the starting point of the feeding stage (the semi-batch stage) and the solid content of the final latex were critical to reducing the amount of coagulum.The monomer feeding of the second stage should start after monomer conversion 40% of the first stage and the solid content of the final latex should remain below 40%.Under such conditions little coagulum was observed.It was concluded that the two-stage semi-batch RAFT mini-emulsion polymerization was effective to synthesize higher molecular weight polymer (~8×104 g•mol-1) with narrow molecular weight distribution (PDI=~1.3) and low residues of the surfactant and co-stabilizer (~1.5%,mass).

Key words: 活性自由基聚合, RAFT聚合, 细乳液聚合, 半连续聚合