Role of Vulcanizing Additives on the Segmental Dynamics of Natural Rubber
Role of Vulcanizing Additives on the Segmental Dynamics of Natural Rubber
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DOI：
10.1021/ma202325k
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发表时间：
2012-01-24
期刊：
影响因子：
5.5
通讯作者：
Lopez-Manchado, Miguel A.
中科院分区：
文献类型：
--
作者：
Hernandez, Marianella;Ezquerra, Tiberio A.;Lopez-Manchado, Miguel A.
采用宽带介电光谱法研究了硫化助剂的加入对未硫化天然橡胶（NR）分子动力学的影响。结果显示NR的节段动力学减缓，限制了链紧密结合到添加剂表面的运动。一般来说，当氧化锌存在时，第二个动态过程被检测到，归因于锌离子团簇和NR聚合物段之间的强界面相互作用。在硫化前研究这种相互作用是控制硫化过程，使其效益最大化，从而改善最终产品的非常有用的策略。在这里，我们证明了宽带介电光谱是一个很好的实验选择，以便更深入地了解硫化机理。此外，我们的研究结果支持了先前提出的硫硫化机制，其中促进剂分子，硫和脂肪酸被吸附在氧化锌表面。
The influence of the addition of vulcanizing additives on the molecular dynamics of unvulcanized natural rubber (NR) has been studied by broadband dielectric spectroscopy. Results reveal a slowdown of the segmental dynamics of NR, restricting the motion of the chains tightly bounded to the additive surfaces. In general, when zinc oxide is present a second dynamic process is detected, ascribed to strong interfacial interactions between the zinc ionic clusters and the NR polymer segments. The study of such interactions prior to vulcanization is a very useful strategy to control the vulcanization process, maximizing its benefits and, hence, improving the final products. Here, we demonstrate that broadband dielectric spectroscopy is a good experimental alternative in order to obtain a deeper insight into the vulcanization mechanisms. Furthermore, our results support one previously proposed sulfur vulcanization mechanism, in which molecules of accelerators, sulfur, and fatty acids are adsorbed on the zinc oxide surface.