Abstract The aim of this study was to evaluate the various roles of 1,3-DiPhenyl Guanidine (DPG) in silica-reinforced rubber compounds. Two roles of DPG are well known to be: adsorption onto silica surface to reduce the acidic sites and second to boost the silanization reaction as secondary accelerator. However, these two roles are in a way conflicting. When DPG molecules occupy the reactive silanol sites on silica by adsorption, then the access of silane molecules needed for silica-rubber coupling is blocked. Therefore, it may be assumed that there is another role DPG plays in silica filled rubber compounds. In order to evaluate another role which can reconcile these contradictory functions of DPG, a series of rubber compound mixings was performed with different DPG concentrations in the masterbatch and final stages. Additionally, a series of model reaction experiments has been done in combination with other ingredients, such as zinc oxide and stearic acid. According to the results a new role of DPG is observed: DPG possibly reacts with the silane coupling agent bis-(triethoxysilylpropyl)tetrasulfide (TESPT) and releases sulfur during the mixing process, which enhances filler-polymer coupling, but reduces cure rate and crosslink density.

中文翻译：

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关于 1,3-二苯基胍在二氧化硅/硅烷增强 sbr/br 共混物中的各种作用

摘要 本研究的目的是评估 1,3-二苯基胍 (DPG) 在白炭黑增强橡胶化合物中的各种作用。众所周知，DPG 的两个作用是：吸附到二氧化硅表面以减少酸性位点，其次作为辅助促进剂促进硅烷化反应。然而，这两个角色在某种程度上是矛盾的。当 DPG 分子通过吸附占据二氧化硅上的反应性硅烷醇位点时，二氧化硅-橡胶偶联所需的硅烷分子的进入被阻断。因此，可以假设 DPG 在二氧化硅填充的橡胶化合物中扮演着另一个角色。为了评估可以调和 DPG 的这些相互矛盾的功能的另一个作用，在母料和最终阶段用不同的 DPG 浓度进行了一系列橡胶化合物混合。此外，结合氧化锌和硬脂酸等其他成分进行了一系列模型反应实验。根据结果​​观察到 DPG 的新作用：DPG 可能与硅烷偶联剂双-(三乙氧基甲硅烷基丙基)四硫化物 (TESPT) 反应并在混合过程中释放硫，这增强了填料-聚合物的偶联，但降低了固化速度和交联密度。