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Please use this identifier to cite or link to this item: http://hdl.handle.net/1942/14411

Title: Single-pulse pulsed laser polymerization-electron paramagnetic resonance investigations into the termination kinetics of n-butyl acrylate macromonomers
Authors: Barth, Johannes
Buback, Michael
Barner-Kowollik, Christopher
Junkers, Thomas
Russell, Gregory T.
Issue Date: 2012
Publisher: WILEY-BLACKWELL
Citation: JOURNAL OF POLYMER SCIENCE PART A-POLYMER CHEMISTRY, 50 (22), p. 4740-4748
Abstract: The termination of model mid-chain radicals (MCRs), which mimic radicals that occur in acrylate polymerization over a broad range of reaction conditions, has been studied by single-pulse pulsed laser polymerization (SP-PLP) in conjunction with electron paramagnetic resonance spectroscopy. The model radicals were generated by initiator-fragment addition to acrylic macromonomers that were preformed prior to the kinetic experiments, thus enabling separation of termination from the propagation reaction, for these model radicals propagate sparingly, if at all, on the timescale of SP-PLP experiments. Termination rate coefficients of the MCRs were determined in the temperature range of 060 degrees C in acetonitrile and butyl propionate solution as well as in bulk macromonomer over the range of 0100 degrees C. Termination rate coefficients slightly below those of the corresponding secondary radicals were deduced, demonstrating the relatively high termination activity of this species, even when undergoing MCRMCR termination. For chain length of 10, a reduction by a factor of 6 is observed. Unusually high activation energies were found for the termination rate coefficient in these systems, with 35 kJ mol-1 being determined for bulk macromonomer. (C) 2012 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2012
Notes: [Russell, Gregory T.] Univ Canterbury, Dept Chem, Christchurch 1, New Zealand. [Barth, Johannes; Buback, Michael] Univ Gottingen, Inst Phys Chem, D-37077 Gottingen, Germany. [Barner-Kowollik, Christopher] KIT, Inst Tech Chem & Polymerchem, D-76128 Karlsruhe, Germany. [Junkers, Thomas] Univ Hasselt, Inst Mat Res, Polymer React Design Grp, B-3590 Diepenbeek, Belgium.
URI: http://hdl.handle.net/1942/14411
DOI: 10.1002/pola.26295
ISI #: 000309925000017
ISSN: 0887-624X
Category: A1
Type: Journal Contribution
Validation: ecoom, 2013
Appears in Collections: Research publications

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