Zhang Ganggang, Feng Haoran, Liang Kuan, Wang Zhao, Li Xiaolin, Zhou Xinxin, Guo Baochun, Zhang Liqun
Beijing Advanced Innovation Center for Soft Matter Science and Engineering, State Key Laboratory of Organic-Inorganic Composites, Beijing University of Chemical Technology, Beijing 100029, China.
Beijing Advanced Innovation Center for Soft Matter Science and Engineering, State Key Laboratory of Organic-Inorganic Composites, Beijing University of Chemical Technology, Beijing 100029, China.
Sci Bull (Beijing). 2020 Jun 15;65(11):889-898. doi: 10.1016/j.scib.2020.03.008. Epub 2020 Mar 10.
Currently adopted cross-linking methods in rubber industry are suffering from variable persistent issues, including the utilization of toxic curing packages, release of volatile organic compounds (VOCs) and difficulties in the recycling of end-of-life materials. It is of great importance to explore a green cross-linking strategy in the area. Herein, we report a new "green" strategy based on hydrolyzable ester cross-links for cross-linking diene-typed elastomers. As a proof of concept, a commercial carboxylated nitrile rubber (XNBR) is efficiently cross-linked by a bio-based agent, epoxidized soybean oil (ESO), without any toxic additives. ESO exhibits an excellent plasticization effect and excellent scorch safety for XNBR. The cross-linking density and mechanical properties of the ESO-cured XNBR can be manipulated in a wide range by changing simply varying the content of ESO. In addition, zinc oxide (ZnO) performs as a catalyst to accelerate the epoxide opening reaction and improve the cross-linking efficiency, serving as reinforcement points to enhance the overall mechanical properties of the ESO-cured XNBR. Furthermore, the end-of-life elastomer materials demonstrate a closed-loop recovery by selectively cleaving the ester bonds, resulting in very high recovery of the mechanical performance of the recycled composites. This strategy provides an unprecedented green avenue to cross-link diene elastomers and a cost-effective approach to further recycle the obtained cross-linked elastomers at high efficiency.
橡胶工业目前采用的交联方法存在各种持续性问题，包括使用有毒的硫化体系、释放挥发性有机化合物（VOCs）以及废弃材料回收困难等。在该领域探索一种绿色交联策略具有重要意义。在此，我们报道了一种基于可水解酯交联的新型“绿色”策略，用于二烯类弹性体的交联。作为概念验证，一种商业羧基丁腈橡胶（XNBR）通过一种生物基试剂环氧大豆油（ESO）进行有效交联，无需任何有毒添加剂。ESO对XNBR表现出优异的增塑效果和焦烧安全性。通过简单改变ESO的含量，ESO硫化的XNBR的交联密度和力学性能可在很宽的范围内进行调控。此外，氧化锌（ZnO）作为催化剂加速环氧开环反应并提高交联效率，同时作为增强点提升ESO硫化的XNBR的整体力学性能。此外，废弃弹性体材料通过选择性裂解酯键实现闭环回收，使得回收复合材料的力学性能具有很高的回收率。该策略为二烯弹性体交联提供了一条前所未有的绿色途径，以及一种经济高效的方法来进一步高效回收所得的交联弹性体。
