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Please use this identifier to cite or link to this item: http://hdl.handle.net/1942/12346

Title: Formation of Triblock Copolymers via a Tandem Enhanced Spin Capturing-Nitroxide-Mediated Polymerization Reaction Sequence
Authors: JUNKERS, Thomas
Zang, Lin
Wong, Edgar H. H.
Dingenouts, Nico
Barner-Kowollik, Christopher
Issue Date: 2011
Abstract: The preparation of ABA-type block copolymers via tandem enhanced spin capturing polymerization (ESCP) and nitroxide-mediated polymerization (NMP) processes is explored in-depth. Midchain alkoxyamine functional polystyrenes (M(n) = 6200, 12,500 and 19,900 g mol(-1)) were chain extended with styrene as well as tert-butyl acrylate at elevated temperature NMP conditions (T = 110 degrees C) generating a tandem ESCP-NMP sequence. Although the chain extensions and thus the block copolymer formation processes function well (yielding in the case of the chain extension with styrene number average molecular weights of up to 20,800 g mol(-1) (PDI = 1.22) when the 6200 g mol(-1) precursor is used and up to 67,500 g mol(-1) (PDI = 1.36) when the 19,900 g mol(-1) precursor is used and 21,600 g mol(-1) (PDI = 1.17) as well as 37,100 g mol(-1) (PDI = 1.21) for the tert-butyl acrylate chain extensions for the 6200 and 12,500 g mol(-1) precursors, respectively), it is also evident that the efficiency of the block copolymer formation process decreases with an increasing chain length of the ESCP precursor macromolecules (i.e., for the 19,900 g mol(-1) ESCP precursor no efficient chain extension with tert-butyl acrylate can be observed). For the polystyrene-block-tert-butyl acrylate-block-polystyrene polymers, the molecular weights were determined via triple detection SEC using light scattering and small-angle X-ray scattering. (C) 2011 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 49: 4841-4850, 2011
Notes: [Junkers, T; Zang, L; Wong, EHH; Dingenouts, N; Barner-Kowollik, C] Karlsruhe Inst Technol, Inst Tech Chem & Polymerchem, D-76128 Karlsruhe, Germany. [Junkers, T] Univ Hasselt, Inst Mat Res, Polymer React Design Grp, B-3590 Diepenbeek, Belgium. thomas.junkers@uhasselt.be; christopher.barner-kowollik@kit.edu
URI: http://hdl.handle.net/1942/12346
DOI: 10.1002/pola.24970
ISI #: 000296255900015
ISSN: 0887-624X
Category: A1
Type: Journal Contribution
Validation: ecoom, 2012
Appears in Collections: Research publications

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