The coupling agent TESPT (bis-[3-(triethoxysilyl)propyl] tetrasulfide) was modified by substituting polyisoprenyl (PI) carbanions for the ethoxyl groups on silicon for increasing the interaction of rubber with its fillers. The modification was carried out by the reaction of TESPT with polyisoprenyllithium, which had been previously prepared by anionic polymerization of isoprene using butyllithium. The success of the substitution was confirmed by Fourier-transform infrared spectroscopy, and the molecular weight of the modified TESPT (PI-TESPT) was determined from gel permeation chromatography measurements. The effects of tethered PI, as well as of its chain length, on the mechanical and dynamic properties of rubber compounds were examined using a universal testing machine and dynamic mechanical analysis (DMA). In rubber sample preparation, the amount of PI₃-TESPT (PI of 2900 g/mol) used in rubber compounding is equal to that of the reference sample with TESPT (S_TESPT). For S_PI-TESPT samples, the amounts of PI₆-TESPT (PI of 5500 g/mol) and PI₁₄-TESPT (PI of 13,700 g/mol) used were calculated as molar ethoxyl groups which are nearly equivalent to those of PI₃-TESPT. At the same wt % (parts per hundred, phr) of elemental sulfur in rubber compounds, despite the order of cross-linking density being S_TESPT (sample prepared with TESPT) > S_PI3-TESPT > S_PI6-TESPT > S_PI14-TESPT, the exhibited tensile strength is of the order of S_PI3-TESPT > S_PI6-TESPT > S_TESPT ≈ S_PI14-TESPT. The better mechanical properties of S_PI3-TESPT, as opposed to those of S_TESPT, could be attributed to the extra reinforcement from the PI–rubber chain linkage and better silica dispersion, as suggested by the mixing torque and Payne effect (ΔG′) measurements. While the dynamic properties of S_PI3-TESPT are inferior to those of S_TESPT, these properties can be improved by adding more elemental sulfur to increase the cross-linking density.

中文翻译：

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聚异戊烯基碳负离子取代双[3-（三乙氧基甲硅烷基）丙基]四硫键的乙氧基对炭黑和二氧化硅增强的NR / SSBR性能的影响

通过用聚异戊二烯（PI）碳负离子取代硅上的乙氧基来修饰偶联剂TESPT（双-[3-（三乙氧基甲硅烷基）丙基]四硫化物，以增强橡胶与其填料的相互作用。通过TESPT与聚异戊二烯基锂的反应进行改性，该聚异戊二烯基锂先前已通过使用丁基锂通过异戊二烯的阴离子聚合而制备。通过傅里叶变换红外光谱法确认了取代的成功，并且通过凝胶渗透色谱法测量确定了改性TESPT的分子量（PI-TESPT）。使用通用测试仪和动态力学分析（DMA），研究了束缚PI及其链长对橡胶混合物力学和动态性能的影响。在橡胶样品制备中橡胶混炼中使用的_3- TESPT（PI为2900 g / mol）等于带有TESPT的参比样品（S _TESPT）。对于S _PI-TESPT样品，所用的PI ₆ -TESPT（PI为5500 g / mol）和PI ₁₄ -TESPT（PI为13,700 g / mol）的量计算为乙氧基摩尔基团，与PI几乎相等_3-测试 尽管交联密度的顺序为S _TESPT（用TESPT制备的样品）> S _{PI 3 -TESPT} > S _{PI 6 -TESPT}，但在橡胶化合物中，元素硫中的硫含量相同（百分数，份/_百分率）>小号_{PI 14 -TESPT}，展出拉伸强度的顺序的小号_{PI 3 -TESPT} >小号_{PI 6 -TESPT} >小号_TESPT ≈小号_{PI 14 -TESPT}。与S _TESPT相比，S _{PI 3 -TESPT}的更好的机械性能可以归因于PI-橡胶链键的额外增强和更好的二氧化硅分散性，如混合扭矩和Payne效应所暗示（ΔG '） 测量。而动态特性S _{PI 3 -TESPT}劣于S _TESPT的那些，可以通过添加更多的元素硫以增加交联密度来改善这些性能。