Semibatch RAFT polymerization for producing ST/BA copolymers with controlled gradient composition profiles

Authors

  • Xiaoying Sun,

    1. The State Key Laboratory of Chemical Engineering, Dept. of Chemical and Biochemical Engineering, Zhejiang University, Hangzhou 310017, People's Republic of China
    2. School of Biological and Chemical Engineering, Zhejiang University of Science and Technology, Hangzhou 310012, People's Republic of China
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  • Yingwu Luo,

    Corresponding author
    1. The State Key Laboratory of Chemical Engineering, Dept. of Chemical and Biochemical Engineering, Zhejiang University, Hangzhou 310017, People's Republic of China
    • State Key Laboratory of Polymer Reaction Engineering, Dept. of Chemical and Biochemical Engineering, Zhejiang University, Hangzhou 310017, People's Republic of China
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  • Rui Wang,

    1. The State Key Laboratory of Chemical Engineering, Dept. of Chemical and Biochemical Engineering, Zhejiang University, Hangzhou 310017, People's Republic of China
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  • Bo-Geng Li,

    Corresponding author
    1. The State Key Laboratory of Chemical Engineering, Dept. of Chemical and Biochemical Engineering, Zhejiang University, Hangzhou 310017, People's Republic of China
    • State Key Laboratory of Polymer Reaction Engineering, Dept. of Chemical and Biochemical Engineering, Zhejiang University, Hangzhou 310017, People's Republic of China
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  • Shiping Zhu

    Corresponding author
    1. Dept. of Chemical Engineering, McMaster University, Hamilton, Ontario, Canada L8S 4L7
    • Dept. of Chemical Engineering, McMaster University, Hamilton, Ontario, Canada L8S 4L7
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Abstract

With controlled/living radical copolymerization, the composition profile along polymer chains becomes a tunable parameter in preparing copolymer products for novel materials properties. In this work, a novel series of styrene/butyl acrylate (St/BA) copolymers with precisely designed composition profiles (uniform, linear gradient, tanh gradient, and triblock with a linear gradient mid-block) were produced using a semibatch reversible addition-fragmentation chain transfer copolymerization mediated by benzyl dithioisobutyrate. The comonomer feeding rate was programmed based on a kinetic model with the targeted composition profile as an objective functions. The experimental composition and molecular weight profiles agreed very well with the model predictions. The polymer molecular weight distributions were narrow with polydispersity index values about 1.3. The amount of dead chains was controlled below 10%. The glass transition behaviors of the St/BA copolymers were evaluated and their Tg values were found to be in an order of uniform < linear gradient < tanh gradient < triblock with 10°C for uniform and 140°C for triblock copolymers. © 2008 American Institute of Chemical Engineers AIChE J 2008

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