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RAFT polymerization of a novel allene-derived asymmetrical divinyl monomer: A facile strategy to alkene-functionalized hyperbranched vinyl polymers with high degrees of branching

Authors

  • Youmei Bao,

    1. State Key Laboratory of Polymer Physics and Chemistry, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun, China
    2. University of the Chinese Academy of Sciences, Changchun Branch, Changchun, China
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  • Guorong Shen,

    1. State Key Laboratory of Polymer Physics and Chemistry, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun, China
    2. University of the Chinese Academy of Sciences, Changchun Branch, Changchun, China
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  • Xiaohui Liu,

    1. School of Materials Science and Engineering, Key Laboratory of Hollow Fiber Membrane Material and Processes of Ministry of Education, Tianjin Polytechnic University, Tianjin, China
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  • Yuesheng Li

    Corresponding author
    • State Key Laboratory of Polymer Physics and Chemistry, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun, China
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Correspondence to: Y. Li ( E-mail:  ysli@ciac.jl.cn)

ABSTRACT

Hyperbranched vinyl polymers with high degrees of branching (DBs) up to 0.43 functionalized with numerous pendent allene groups have been successfully prepared via reversible addition fragmentation chain transfer polymerization of a state-of-art allene-derived asymmetrical divinyl monomer, allenemethyl methacrylate (AMMA). The gelation did not occur until high monomer conversions (above 90%), as a result of the optimized reactivity difference between the two vinyl groups in AMMA. The branched structure was confirmed by a combination of a triple-detection size exclusion chromatography (light scattering, refractive index, and viscosity detectors) and detailed 1H NMR analyses. A two-step mechanism is proposed for the evolution of branching according to the dependence of molecular weight and DB on monomer conversion. Controlled radical polymerization proceeds until moderate conversions, mainly producing linear polymers. Subsequent initiation and propagation on the polymerizable allene side chains as well as the coupling of macromolecular chains generate numerous branches at moderate-to-high monomer conversions, dramatically increasing the molecular weight of the polymer. AMMA was also explored as a new branching agent to construct poly(methyl methacrylate)-type hyperbranched polymers by its copolymerization with methyl methacrylate. The DB can be effectively tuned by the amount of AMMA, showing a linear increase trend. The pendent allene groups in the side chains of the copolymers were further functionalized by epoxidation and thiol-ene chemistry in satisfactory yields. © 2013 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2013, 51, 2959–2969

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