Termination Kinetics of the Free-Radical Polymerization of Nonionized Methacrylic Acid in Aqueous Solution
Termination Kinetics of the Free-Radical Polymerization of Nonionized Methacrylic Acid in Aqueous Solution
复制标题
非离子甲基丙烯酸在水溶液中自由基聚合的终止动力学
DOI：
10.1021/ma7028902
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发表时间：
2008
期刊：
影响因子：
5.5
通讯作者：
I. Lacík
中科院分区：
文献类型：
--
作者：
S. Beuermann;M. Buback;P. Hesse;R. Hutchinson;Silvia Kukučková;I. Lacík
通过单脉冲脉冲激光引发聚合，并结合通过近红外光谱 (SP−PLP−NIR) 进行的 µs 时间分辨在线监测单体转化，研究了两种 MAA 浓度（30 wt% 和 60 wt%）下水溶液中非离子甲基丙烯酸（MAA）自由基聚合的终止动力学。根据 2000 bar 的 kt/kp 测量值，以及从文献数据推断出的与转化率相关的传播速率系数 kp，链长平均终止速率系数 ⟨kt⟩ 可以作为单体转化率 x 的函数推导出来。与甲基丙烯酸甲酯聚合一样，⟨kt⟩ 与 x 的依赖性可以在以下假设下进行建模：对于更高程度的单体转化，⟨kt⟩ 依次由分段扩散、平移扩散和反应扩散控制。对于 50 °C、2000 bar 和水中初始单体浓度为 30 和 60 wt% 的情况，化学引发的聚合反应也已...
The termination kinetics of free-radical polymerization of nonionized methacrylic acid (MAA) in aqueous solution has been investigated at two MAA concentrations, 30 and 60 wt %, by single-pulse pulsed-laser initiated polymerization carried out in conjunction with µs time-resolved in-line monitoring of monomer conversion via near-infrared spectroscopy (SP−PLP−NIR). From measured values of kt/kp for 2000 bar, with the conversion-dependent propagation rate coefficient, kp, being inferred from literature data, the chain-length-averaged termination rate coefficient, ⟨kt⟩, is deduced as a function of monomer conversion, x. As with methyl methacrylate polymerization, the ⟨kt⟩ vs x dependence may be modeled under the assumption that, toward higher degrees of monomer conversion, ⟨kt⟩ is successively controlled by segmental diffusion, translational diffusion, and reaction diffusion. For 50 °C, 2000 bar, and initial monomer concentrations in water of 30 and 60 wt %, chemically initiated polymerizations have also bee...