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Rate constant measurements for initial addition reactions of radicals at the propagation step of photo‐polymerization as studied by pulsed EPR spectroscopy |
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| Authors: | Yusuke Miyake Yutaka Marushima Hirona Takahashi Nobuyuki Akai Kazuhiko Shibuya Akio Kawai |
| Affiliation: | 1. Department of Chemistry, Graduate School of Science and Engineering, Tokyo Institute of Technology, Meguro‐ku, Tokyo, Japan;2. Faculty of Molecular Chemistry and Engineering, Graduate School of Science and Technology, Kyoto Institute of Technology, Sakyo‐ku, Kyoto, Japan;3. Graduate School of Bio‐Applications and Systems Engineering, Tokyo University of Agriculture and Technology, Koganei, Tokyo, Japan |
| Abstract: | Pulsed EPR spectroscopy was employed to determine reaction rate constants at an early stage of addition reactions in radical polymerizations triggered by four initiator radicals, which were generated by photodissociation of four parent molecules. Two monomers (tert‐butylacrylate and tert‐butylmethacrylate) were examined as reactant. Stern–Volmer analysis on the measured decay time of electron spin echo intensity of reacting radicals provides rate constants for addition reactions. We focused on rate constants for the second step reaction between monomer and adduct radical that is produced by the first step addition reaction between initiator radical and monomer. The rate constant measured by pulsed EPR was evaluated by theoretical calculations in the light of (1) enthalpy difference between product radical and reactants and (2) charge transfer interaction between reacting radical and monomer. Copyright © 2016 John Wiley & Sons, Ltd. |
| Keywords: | addition reaction photo‐polymerization pulsed EPR rate constant measurement time‐resolved EPR |