Propagation rate coefficients from electron spin resonance studies of the emulsion polymerization of methyl methacrylate
Propagation rate coefficients from electron spin resonance studies of the emulsion polymerization of methyl methacrylate
复制标题
甲基丙烯酸甲酯乳液聚合的电子自旋共振研究的传播速率系数
DOI：
10.1021/ma00159a004
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发表时间：
1986
期刊：
影响因子：
5.5
通讯作者：
J. H. O′donnell
中科院分区：
文献类型：
--
作者：
M. Ballard;R. Gilbert;D. H. Napper;P. J. Pomery;P. W. O'Sullivan;J. H. O′donnell
报告了 ESR 光谱在乳液聚合动力学中的定量应用的第一个结果。当该技术与膨胀速率测量相结合应用于 50 °C 下甲基丙烯酸甲酯的种子乳液聚合时，发现增长速率系数 (k) 对聚合物重量分数 (W) 的依赖性为 k = k° (0.33 ≤ w≤ 0.84) 和 k exp{-29.8[w - 0.84]} (0.84 ≤ w≤ 0.99)，其中 k° = 790 ± 300 分毫摩尔秒。这些结果反映了乳胶颗粒通过其玻璃化转变点（w = 0.84）的过程，导致增长步骤受到单体扩散到增长位置的控制。观察到的 kfor w> 0.84 的下降似乎没有当前自由体积理论预测的那么显着。
The first results are reported for the quantitative application of ESR spectroscopy to emulsion polymerization kinetics. When this technique, in conjunction with dilatometric rate measurements, was applied to the seeded emulsion polymerization of methyl methacrylate at 50 °C, the dependence of the propagation rate coefficient (k) on the weight fraction of polymer (W) was found to be k = k° (0.33 ≤ w≤ 0.84) and k exp{-29.8[w - 0.84]} (0.84 ≤ w≤ 0.99), where k° = 790 ± 300 dmmol s. These results reflect the passage of the latex particles through their glass transition point (at w= 0.84), leading to the propagation step being controlled by the diffusion of monomer to the propagation site. The observed decrease in kfor w> 0.84 appears to be less dramatic than that predicted by current free volume theories.