RAFT ab initio emulsion copolymerization of ¦Ã-methyl-¦Á-methylene-¦Ã-butyrolactone and styrene

详细信息    查看全文

• 作者：Shaohong Xu ; Jie Huang ; Song Xu ; Yingwu Luo ; ^{yingwu.luo@zju.edu.cn}
• 关键词：Gradient copolymer ; RAFT polymerization ; Emulsion polymerization
• 刊名：Polymer
• 出版年：2013
• 出版时间：22 March, 2013
• 年：2013
• 卷：54
• 期：7
• 页码：1779-1785
• 全文大小：439 K

文摘

RAFT ab initio emulsion copolymerization of ¦Ã-methyl-¦Á-methylene-¦Ã-butyrolactone (MeMBL) and styrene with various monomer ratios was investigated with PAA₂₀-PS₅ trithiocarbonate being mediator and surfactant at 70?¡ãC. The polymerization was fully controlled as evidenced by stable latexes, well predicted molecular weights and low PDIs about 1.2 when [MeMBL]:[St]?¡Ü?1:2. However, in the case of [MeMBL]:[St]?=?1:1, the molecular weight became out of control due to gel effect of RAFT reactions. The relatively water-soluble MeMBL was found to dramatically influence the polymerization kinetics and copolymer properties, as evidenced by (1) No inhibition period was observed; (2) The copolymer compositions in the early stage of polymerization were much higher than those predicted by the Mayo-Lewis equation in the case of [MeMBL]:[St]?=?1:2, leading to the formation of linear gradient copolymer. (3) T_gs of the copolymers from emulsion copolymerization were higher than those from bulk copolymerization. It was concluded that we could synthesize the gradient copolymer with preset molecular weight and low PDI in RAFT emulsion polymerization, T_g of which should be much higher than 100?¡ãC.