Termination, Propagation, and Transfer Kinetics of Midchain Radicals in Methyl Acrylate and Dodecyl Acrylate Homopolymerization
Termination, Propagation, and Transfer Kinetics of Midchain Radicals in Methyl Acrylate and Dodecyl Acrylate Homopolymerization
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丙烯酸甲酯和丙烯酸十二烷基酯均聚中链自由基的终止、传播和转移动力学
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发表时间：
2018
期刊：
影响因子：
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通讯作者：
M. Buback
中科院分区：
文献类型：
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作者：
H. Kattner;M. Buback
丙烯酸甲酯（MA）和丙烯酸十二烷基酯（DA）均聚（1.5 M的甲苯）进行了研究，通过单脉冲脉冲激光聚合结合检测的类型和浓度的自由基的电子顺磁共振光谱（SP-PLP-EPR）。在0至60 °C的温度范围内，以微秒的时间分辨率测量了瞬时激光诱导产生初级自由基的强烈爆发后次级传播（SPR）和中链（MCR）自由基的演变。与链长依赖性终止和传播的SPR的动力学已经从实验中已知在零度以下的温度下，从SPR，kbb，从MCR的传播，kpt，和交叉终止之间的SPR和MCR，ktst，推导出的速率系数为形成MCR从SPRs的背咬。本文旨在阐明酯侧链的大小对kbb，kpt和ktst的影响。从MA到DA（在1.5M甲苯溶液中）的速率为：
Methyl acrylate (MA) and dodecyl acrylate (DA) homopolymerizations (1.5 M in toluene) were investigated via single pulse–pulsed laser polymerization in conjunction with detection of the type and of the concentration of radicals by electron paramagnetic resonance spectroscopy (SP–PLP–EPR). The evolution of secondary propagating (SPR) and midchain (MCR) radicals, after instantaneous laser-induced production of an intense burst of primary radicals, was measured with a time resolution of microseconds from 0 to 60 °C. With the kinetics of chain-length-dependent termination and of propagation for SPRs being already known from experiments at subzero temperature, the rate coefficients for the formation of MCRs from SPRs by backbiting, kbb, of propagation from MCRs, kpt, and of cross-termination between an SPR and an MCR, ktst, were deduced. The present paper aims at elucidating the impact of the size of the ester side chain on kbb, kpt, and ktst. In passing from MA to DA (in 1.5 M solution of toluene), the rate c...