Dinuclear Bridging Bidentate Zinc/Stearate Complex in Sulfur Cross-Linking of Rubber

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• 作者：Yuko Ikeda ; Yoritaka Yasuda ; Takumi Ohashi ; Hiroyuki Yokohama ; Shinya Minoda ; Hisayoshi Kobayashi ; Tetsuo Honma
• 刊名：Macromolecules
• 出版年：2015
• 出版时间：February 10, 2015
• 年：2015
• 卷：48
• 期：3
• 页码：462-475
• 全文大小：731K
• ISSN：1520-5835

文摘

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 (Zn₂(渭-O₂CC₁₇H₃₅)₂)²⁺(OH^{鈥?/sup>)₂路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.}