Disulfide bond has unique advantages in the preparation of recyclable rubbers since it not only shows similar sulfur structure to the crosslinks of traditional sulfide rubber systems but also can rearrange and exchange itself under mild external conditions. However, the reported disulfide bond-crosslinked rubbers often exhibit weak tensile strength or poor elongation because of the inappropriate disulfide bond content. Although some disulfide bond incorporated dual-crosslinked rubbers can combine good tensile strength with high elongation, the dual-crosslinked design always requires multi-step chemical modification in the solvent, which is complex and difficult for industrial operation. In this work, aromatic disulfide bonds are introduced into epoxidized natural rubber (ENR) as the vulcanizing agent by a simple one-step method. It is found that the elongation of rubbers can be more than 1100 % with the tensile strength up to 7 MPa when 2.1 phr of 2,2′-dithiosalicylic acid is added. The quantitative relationship between the content of aromatic disulfide bonds and the mechanical properties of ENR is systematically studied, as well as the exchangeable behaviors of disulfide bonds. The research results of this work will not only provide a facile route for preparing rubbers with easily industrial operation and high stretchability, but also contribute to the in-depth understanding of the mechanism of disulfide bonds.

中文翻译：

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一种高度可拉伸的二硫化物交联环氧化天然橡胶，采用一步法


二硫键在制备可回收橡胶方面具有独特的优势，因为它不仅显示出与传统硫化物橡胶体系交联相似的硫结构，而且可以在温和的外部条件下重新排列和交换。然而，由于二硫键含量不合适，报道的二硫键交联橡胶通常表现出较弱的拉伸强度或伸长率差。虽然一些掺入二硫键的双交联橡胶可以将良好的拉伸强度和高伸长率相结合，但双交联设计总是需要在溶剂中进行多步化学改性，这对于工业操作来说既复杂又困难。在这项工作中，通过简单的一步法将芳香族二硫化键作为硫化剂引入环氧化天然橡胶 （ENR） 中。研究发现，当添加 2.1 份 2,2′-二硫代水杨酸时，橡胶的伸长率可以超过 1100%，拉伸强度高达 7 MPa。系统研究了芳香族二硫键含量与 ENR 机械性能之间的定量关系，以及二硫键的可交换行为。这项工作的研究成果不仅将为制备易于工业操作和高拉伸性的橡胶提供一条简便的路线，而且有助于深入了解二硫键的机理。