Flex life of three different grades of polybutadiene rubber (BR) with highly linear chains, linear chains and long-branched chains was measured. The rubbers were reinforced with a precipitated silica nanofiller, the surface of which had been pre-treated with sulphur-bearing bis(3-triethoxysilylpropyl-)-tetrasulphane (TESPT) coupling agent. The rubbers were cured by reacting the sulphur in TESPT with the rubber chains to produce vulcanisates. The mechanical properties of the rubber vulcanisates such as tensile strength, Young’s modulus, elongation at break, stored energy density at break and tear energy were subsequently determined. The flex life of the rubber vulcanisates was also measured at a constant maximum strain amplitude and a test frequency of 3.17 Hz at ambient temperature. Additionally, the flex life of some unfilled rubber vulcanisates of similar Mooney viscosities cured with elemental sulphur was also measured. For the silica-filled rubber vulcanisate, the rubber with the highly linear chains had the longest flex life and the one with long-branched chains, the shortest flex life. It seemed that a correlation between the flex life and the molecular chains structure might exist despite the crosslink density of the rubber vulcanisates being different and the compounds having silica in them. For the unfilled rubber vulcanisates, the rubber with highly linear chains had the longest flex life and the one with linear chains the shortest flex life. Therefore, it was concluded that the flex life of the rubber vulcanisate was determined, to a large extent, by the molecular chains structure of the raw rubber, irrespective of whether the rubber had reinforcing silica filler, different crosslink densities and different initial viscosities or not. A similar trend was also observed for some of the mechanical properties. For example, the elongation at break was lower and Young’s modulus higher for the silica-filled rubber vulcanisates with long-branched chains than those measured for the silica-filled rubber vulcanisate with highly linear chains.

中文翻译：

---

影响聚丁二烯橡胶硫化胶弯曲寿命的一些因素

测量了具有高度线性链，线性链和长支链的三种不同等级的聚丁二烯橡胶（BR）的挠曲寿命。橡胶用沉淀的二氧化硅纳米填料增强，其表面已经用含硫的双（3-三乙氧基甲硅烷基丙基-）-四硫烷（TESPT）偶联剂进行了预处理。通过使TESPT中的硫与橡胶链反应以生成硫化橡胶来硫化橡胶。随后确定橡胶硫化橡胶的机械性能，例如抗张强度，杨氏模量，断裂伸长率，断裂时储存的能量密度和撕裂能量。在恒定的最大应变幅度和环境温度下的3.17 Hz测试频率下，也测量了橡胶硫化橡胶的挠曲寿命。另外，还测量了一些用元素硫固化的类似门尼粘度的未填充橡胶硫化橡胶的挠曲寿命。对于二氧化硅填充的橡胶硫化橡胶，具有高度线性链的橡胶具有最长的挠曲寿命，而具有长分支链的橡胶具有最短的挠曲寿命。尽管橡胶硫化橡胶的交联密度不同并且其中含有二氧化硅的化合物，但似乎挠曲寿命与分子链结构之间可能存在相关性。对于未填充的橡胶硫化橡胶，具有高线性链的橡胶的挠曲寿命最长，而具有线性链的橡胶的挠曲寿命最短。因此，可以得出结论，橡胶硫化橡胶的挠曲寿命在很大程度上取决于生橡胶的分子链结构，不论橡胶是否具有补强二氧化硅填料，不同的交联密度和不同的初始粘度。对于某些机械性能也观察到类似的趋势。例如，具有长支链的二氧化硅填充的橡胶硫化橡胶的断裂伸长率比具有高度线性链的二氧化硅填充的橡胶硫化橡胶的断裂伸长率低且杨氏模量较高。