Surfactant-free aqueous RAFT polymerization of styrene in the presence of CaCO₃ particles

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• 作者：Chengxin Shang^a ; Jianxiong Xu^b ; Xiaohui Wang^b ; Xu Zhang^b ; Wangqing Zhang^b ; ^{zhangnankai@yahoo.com.cn} ; ^{wqzhang@nankai.edu.cn} ; Tianyong Zhang^a ; ^{tyzhang@tju.edu.cn}
• 关键词：RAFT polymerization ; Surfactant-free aqueous RAFT polymerization ; Inorganic materials
• 刊名：Polymer
• 出版年：2013
• 出版时间：24 January, 2013
• 年：2013
• 卷：54
• 期：2
• 页码：614-622
• 全文大小：1115 K

文摘

A new method to achieve well-controlled surfactant-free aqueous RAFT polymerization of styrene initiated by K₂S₂O₈ in the presence of CaCO₃ particles was proposed. It was found that the hydrophobic monomer of styrene was adsorbed on the surface of CaCO₃ particles and well-controlled surfactant-free aqueous RAFT polymerization mediated with the RAFT agent of S,S¡ä-bis(¦Á,¦Á¡ä-dimethyl-¦Á¡å-acetic acid) trithiocarbonate (BDMAT) was achieved. The weight ratio of the feeding CaCO₃ to the styrene monomer on the aqueous RAFT polymerization was investigated, and it was found that high CaCO₃/styrene weight ratio led to fast aqueous RAFT polymerization. The aqueous RAFT polymerization kinetics was checked, and the fast RAFT polymerization rate at low molar ratio of styrene/BDMAT/K₂S₂O₈, the linear ln([M]_o/[M])-time plot, the linear increase in the number-average molecular weight with the monomer conversion, and the relatively low PDI values (1.1¡«1.3) were demonstrated. The surfactant-free aqueous RAFT polymerization was compared with the general emulsion RAFT polymerization in the presence of the sodium dodecyl sulfate (SDS) surfactant. It was found that the surfactant-free aqueous RAFT polymerization seemed more valid than the emulsion RAFT polymerization. The proposed method is believed to be a new strategy to achieve well-controlled surfactant-free aqueous RAFT polymerization.