New experimental procedure to determine the recombination rate constants between Nitroxides and Macroradicals

Guillaneuf, Y., Bertin, D. and Castignolles, P. (2005) New experimental procedure to determine the recombination rate constants between Nitroxides and Macroradicals. Macromolecules, 38 11: 4638-4646. doi:10.1021/ma050241x


Author Guillaneuf, Y.
Bertin, D.
Castignolles, P.
Title New experimental procedure to determine the recombination rate constants between Nitroxides and Macroradicals
Journal name Macromolecules   Check publisher's open access policy
ISSN 0024-9297
Publication date 2005-05-31
Sub-type Article (original research)
DOI 10.1021/ma050241x
Volume 38
Issue 11
Start page 4638
End page 4646
Total pages 9
Place of publication Washington, D.C.
Publisher American Chemical Society
Language eng
Subject 0303 Macromolecular and Materials Chemistry
Abstract A new experimental procedure for the determination of the recombination rate constant, kc, between a propagating macroradical and a nitroxide is proposed. It is based on a single pulse−pulsed lamp polymerization where the main chain growth breaking event between two consecutive pulses is the recombination of the macroradicals with the nitroxide. The recovered polymer is analyzed by size exclusion chromatography, and the parameters of the molar mass distribution are used to determine kc, in a similar way as that traditionally applied in the determination of the chain transfer rate constants, i.e., the Mayo method using the number- or weight-average degrees of polymerization and the full chain length distribution method. We named the technique RNR−PLP−SEC for radical nitroxide recombination−pulsed lamp polymerization−size exclusion chromatography. The particular polystyryl macroradical−SG1 nitroxide system was tested to validate it. To apply a consistency check, the experimental parameters have been varied according to the recommendations made by the IUPAC for the measurements of the propagation rate constants via PLP. The recombination rate constant kc was measured over a temperature range where no cleavage of the formed alkoxyamine might occur. At 40 °C kc = 2.6 × 105 L mol-1 s-1, and the value increased from 1.1 × 105 L mol-1 s-1 at 15 °C to 4.0 × 105 L mol-1 s-1 at 82 °C. The extrapolation at 120 °C led to 5.3 × 105 L mol-1 s-1, in good agreement with the values already reported in the literature.
Q-Index Code C1
Q-Index Status Provisional Code
Institutional Status Unknown

Document type: Journal Article
Sub-type: Article (original research)
Collections: Excellence in Research Australia (ERA) - Collection
Centre for Nutrition and Food Sciences Publications
 
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