Preparation and kinetic analysis of PS‐b‐PBA block copolymer by 4‐oxo‐TEMPO capped polystyrene macroinitiators |
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| Authors: | Kuo‐Huai Kuo Wen‐Yen Chiu Kuo‐Chung Cheng |
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| Affiliation: | 1. Department of Chemical Engineering, National Taiwan University, Taipei 106, Taiwan;2. Department of Materials Science and Engineering, National Taiwan University, Taipei 106, Taiwan;3. Institute of Polymer Science and Engineering, National Taiwan University, Taipei 106, Taiwan;4. Department of Chemical Engineering and Biotechnology, Institute of Chemical Engineering, National Taipei University of Technology, Taipei 106, Taiwan |
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| Abstract: | Polystyrene‐block‐poly(n‐butyl acrylate) block copolymers were prepared from 4‐oxo‐2,2,6,6‐tetramethylpiperidinooxy (4‐oxo‐TEMPO) capped polystyrene macroinitiators at a high temperature, 165°C. It was found that the number‐average molecular weight of PBA chains in block copolymers could reach above 10,000 rapidly at early stage of polymerization with a narrow polydispersity index of 1.2–1.4, but after that, the polymerization seemed to be retarded. Furthermore, according to the kinetic analysis, the concentration of 4‐oxo‐TEMPO was increased mainly by the hydrogen transfer reaction of hydroxylamine (4‐oxo‐TEMPOH) to growing radicals during polymerization. This increase in 4‐oxo‐TEMPO concentration could retard the growth of polymer chains. The rate constant of the hydrogen transfer reaction of 4‐oxo‐TEMPOH to growing radicals, kH, estimated by the kinetic model is about 9.33 × 104M‐1s?1 at 165°C. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009 |
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| Keywords: | nitroxide‐medicated polymerization block copolymer kinetic model |
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