Zn(MMA)2对硫黄硫化天然橡胶性能的影响

摘要

In the presence of free radicals, grafting and crosslinking reaction of zinc methacrylate (Zn(MMA)2) and rubber can occurred, crosslink structure of metal ion bonds was introduced, nano polysalt particles were generated, which could make the vulcanizate form multiple crosslinking network structure and multiple filling network structure, sothe physical and mechanical properties of vulcanized rubbercould begreatly improved. Usually peroxide curing system can be used in order to achieve the excellent performance of Zn(MMA)2. Although there are a lot of reports about peroxide system/sulfur system, theydo not havegood performance comparing with simply using peroxide vulcanization. Sulfur curing system ismost widely used in unsaturated rubber vulcanization system.So it is significant to obtain excellent performance of Zn(MMA)2 under the condition of sulfur vulcanization. The relative amount of sulfur (S) and Zn(MMA)2 was designed from a stoichiometric standpoint to make that the molar amount of sulfurwas far more than that of Zn(MMA)2(more than 14:1/mol:mol) . The characteristics of natural rubber vulcanized by three kinds of curing systems (S,Zn(MMA)2/S,Zn(MMA)2/S*)werecompared. The results showed that the physical and mechanical propertiesof vulcanizate vulcanized by curing system of Zn(MMA)2/S were improved significantly,which could makeit possible to realize the excellent performance of Zn(MMA)2in sulfur curing system. The reasons for these results were analyzed,and the possible mechanism was put forward.%甲基丙烯酸锌(Zn(MMA)2)在自由基存在下可以与橡胶发生接枝和交联反应,在橡胶中引入金属离子键交联结构,发生自聚合反应生成纳米聚盐粒子等,使得硫化橡胶具有多元的交联网络结构和多元的填充网络结构,这使得硫化胶的物理力学性能大大提高.为了获得Zn(MMA)2所给出的优异性能,需采用过氧化物硫化体系,虽然过氧化物与硫黄并用的体系有很多报道,但是都没有单纯采用过氧化物硫化时的性能好.由于硫黄硫化是不饱和橡胶最广泛采用的硫化体系,因此在硫黄硫化条件下,获得Zn(MMA)2的优异性能,无疑是非常有意义的.从化学计量角度设计了胶料中硫黄的摩尔用量远远大于Zn(MMA)2的摩尔用量(14:1/mol:mol)的情况,对比了三种硫化体系(S、Zn(MMA)2/S、Zn(MMA)2/S*)硫化天然橡胶的特点.结果表明Zn(MMA)2/S体系硫化胶料的物理力学性能显著提高,这使在硫黄硫化体系中实现Zn(MMA)2的优异性能成为可能.论文分析阐述了产生这些结果的原因并提出了可能的机理