Ge Lun, Liu Qiang
Key Laboratory of Rubber-Plastics of Ministry of Education, Qingdao University of Science & Technology, Qingdao 266042, China.
Polymers (Basel). 2022 Jan 24;14(3):461. doi: 10.3390/polym14030461.
To improve the curing reaction rate and efficiency of sulfur-cured diene-based rubbers, the introduction of some chemical compounds as activators and accelerants is inevitably required, causing potential harm to humans and ecological systems. Moreover, silica is usually employed as a green filling material for rubber reinforcement, and a silane coupling agent is always required to improve its dispersion. Herein, we reported an effective method to cure hydroxyl-functionalized rubbers/silica composites with blocked polyisocyanates, avoiding the use of any other additives. The enhanced dispersion of silica by interaction with hydroxyl groups on molecular chains endowed the composites with high-mechanical performance. The mechanical properties and crosslinking kinetics of the resultant silica composites can be regulated by adjusting the content of hydroxyl groups in the rubber, as well as the amount of the blocked polyisocyanates. The dynamic heat build-up was related to the distance between crosslinking points. A SBROH/B-TDI/silica composite prepared with blocked toluene diisocyanatem (TDI) exhibited comparable tanδ (0.21 at 0 °C and 0.11 at 60 °C) to that of silica composites cured by sulfur with the help of a silane coupling agent (SBR/S/Si69/silica, 0.18 and 0.10), suggesting great applicable potential for new tire rubber compounds.
为了提高硫黄硫化二烯基橡胶的硫化反应速率和效率，不可避免地需要引入一些化合物作为活化剂和促进剂，这会对人类和生态系统造成潜在危害。此外，二氧化硅通常用作橡胶增强的绿色填充材料，并且总是需要一种硅烷偶联剂来改善其分散性。在此，我们报道了一种用封端多异氰酸酯硫化羟基官能化橡胶/二氧化硅复合材料的有效方法，避免使用任何其他添加剂。通过与分子链上的羟基相互作用增强二氧化硅的分散性，赋予了复合材料高机械性能。所得二氧化硅复合材料的力学性能和交联动力学可以通过调节橡胶中羟基的含量以及封端多异氰酸酯的用量来调控。动态生热与交联点之间的距离有关。用封端甲苯二异氰酸酯（TDI）制备的SBROH/B-TDI/二氧化硅复合材料在0℃时的损耗因子tanδ为0.21，在60℃时为0.11，与在硅烷偶联剂（SBR/S/Si69/二氧化硅）帮助下用硫黄硫化的二氧化硅复合材料（0.18和0.10）相当，这表明其在新型轮胎橡胶配方中具有巨大的应用潜力。
