Dinuclear Bridging Bidentate Zinc/Stearate Complex in Sulfur Cross-Linking of Rubber
Dinuclear Bridging Bidentate Zinc/Stearate Complex in Sulfur Cross-Linking of Rubber
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DOI：
10.1021/ma502063m
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发表时间：
2015-02-10
期刊：
影响因子：
5.5
通讯作者：
Honma, Tetsuo
中科院分区：
文献类型：
--
作者：
Ikeda, Yuko;Yasuda, Yoritaka;Honma, Tetsuo
利用时间分辨锌K边X射线吸收精细结构和原位红外光谱，提出了异戊橡胶硫交联反应中氧化锌和硬脂酸生成中间体的基本结构。该结构主要是桥接双齿锌/硬脂酸盐络合物，锌离子与硬脂酸盐的摩尔比和配位数分别出乎意料地为1：1和4。结合用于鉴定中间体的密度泛函计算，主要表明其最可能的结构是（Zn-2（μ-O2 CC 17 H35）（2））（2+）（OH）（2）XY，其中X和Y是水和/或橡胶链段。尽管橡胶科学和技术有着悠久的历史，但这种中间体一直是未知的。新观察到的锌/硬脂酸盐络合物可能起到了加速橡胶的硫交联反应的作用，就像酶一样，因为锌离子的高刘易斯活性。
An essential structure of the intermediate generated from zinc oxide and stearic acid during sulfur cross-linking reaction of isoprene rubber is proposed using time-resolved zinc K-edge X-ray absorption fine structure and infrared spectroscopies in situ. The structure is dominantly a bridging bidentate zinc/stearate complex, the molar ratio of the zinc ion to stearate and the coordination number of which are unexpectedly 1:1 and 4, respectively. Combination with a density functional calculation for identifying the intermediate predominantly suggests that its most possible structure is (Zn-2(mu-O2CC17H35)(2))(2+)(OH)(2)XY, where X and Y are water and/or a rubber segment. This intermediate has been unknown despite the long history of rubber science and technology. The newly observed zinc/stearate complex may play a role to accelerate the sulfur cross-linking reaction of rubber like an enzyme because of the high Lewis activity of the zinc ion.