Ab Initio RAFT Emulsion Copolymerization of Styrene and Acrylonitrile

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• 作者：Jie Huang ; Shumiao Zhao ; Xiang Gao ; Yingwu Luo ; Bogeng Li
• 刊名：Industrial & Engineering Chemistry Research
• 出版年：2014
• 出版时间：May 7, 2014
• 年：2014
• 卷：53
• 期：18
• 页码：7688-7695
• 全文大小：392K
• 年卷期：v.53,no.18(May 7, 2014)
• ISSN：1520-5045

文摘

Ab initio RAFT emulsion copolymerization of styrene (St) and acrylonitrile (AN) was investigated by using poly(acrylic acid)₂₀-b-polystyrene₅ trithiocarbonate as surfactant and RAFT agent. The well-controlled polymerization in terms of linear growth of molecular weight, low PDI, and little coagulum could be achieved only when the mass ratio m(St)/m(AN) was greater than 1:1 and suitable polymerization temperature depending on the monomer ratios. A significant amount of coagulum was formed when more AN was used. The gel effect, which led to the diffusion-controlled RAFT addition reactions in the late stage of the polymerization, played a significant influence on the PDI, the degree of which was highly dependent on the targeted molecular weight and monomer compositions. For the copolymerization of styrene and acrylonitrile with the azeotropic composition (75 wt % styrene), the gel effect could be relieved by increasing the reaction temperature from 70 to 90 掳C after the nucleation period, resulting in PDI as low as 1.20. However, in the cases of the higher AN composition, the gel effect was still pronounced. Unexpectedly, the particle number was insensitive to the RAFT agent concentrations.