Rate constant measurements for initial addition reactions of radicals at the propagation step of photo-polymerization as studied by pulsed EPR spectroscopy
Rate constant measurements for initial addition reactions of radicals at the propagation step of photo-polymerization as studied by pulsed EPR spectroscopy
复制标题
通过脉冲 EPR 光谱研究光聚合传播步骤中自由基初始加成反应的速率常数测量
DOI：
10.1002/poc.3566
复制
发表时间：
2016
影响因子：
1.8
通讯作者：
Kazuhiko Shibuya and Akio Kawai
中科院分区：
文献类型：
--
作者：
Yusuke Miyaka;Yutaka Marushima;Hirona Takahashi;Nobuyuki Akai;Kazuhiko Shibuya and Akio Kawai
采用脉冲EPR光谱法测定了四种引发剂自由基引发自由基聚合的早期加成反应速率常数。研究了两种单体（丙烯酸叔丁酯和甲基丙烯酸叔丁酯）作为反应物。Stern-Volmer分析的测量衰减时间的电子自旋回波强度的反应自由基提供了加成反应的速率常数。重点研究了引发剂自由基与单体的第一步加成反应生成的加成自由基与单体的第二步反应的速率常数。根据产物自由基与反应物之间的焓差和反应自由基与单体之间的电荷转移相互作用，对脉冲EPR法测得的反应速率常数进行了理论计算。版权所有© 2016约翰威利父子有限公司.
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 andtert‐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.