Abstract The mechanical properties and the hierarchical filler structures were characterized on a series silica-filled silicone rubber with a filler fraction (ΦSi) varied from 0.05 phr to 80 phr (parts per hundred rubber). Uniaxial elongation measurement suggests that there is a percolation threshold between 10 and 30 phr. Moreover, an optimum ΦSi range from 40 phr to 50 phr is found, in which the best mechanical performances of reinforcement are shown. The microscopic structures were crosschecked by small-angle neutron scattering (SANS) and scanning electron microscopy (SEM). The effects of the ΦSi and the fabrication process on the morphology of samples are unveiled. The correlation length among aggregates extracted from SANS data monotonically decrease from 237.0 nm to 136.5 nm with increasing the ΦSi from 30 phr to 80 phr. The average radius of gyration of aggregates 〈Rg,agg〉 fitted with the Beaucage model monotonically decrease from 49.2 nm to 37.5 nm with increasing ΦSi from 10 phr to 80 phr. Providing a 10 nm thickness bound rubber as bridge, samples with optimum ΦSi yield a morphology that the radii of aggregates and the gap filled with polymer matrix in between are equivalent as both around 60 nm.

中文翻译：

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硅橡胶中优化二氧化硅组分的力学性能与微观结构之间的相关性

摘要 在一系列二氧化硅填充硅橡胶上表征了机械性能和分级填料结构，其中填料分数 (ΦSi) 从 0.05 phr 到 80 phr（每百份橡胶的份数）不等。单轴伸长率测量表明存在 10 到 30 phr 之间的渗透阈值。此外，还发现了 40 至 50 份的最佳 ΦSi 范围，其中显示了最佳的增强机械性能。微观结构通过小角中子散射 (SANS) 和扫描电子显微镜 (SEM) 进行交叉检查。揭示了 ΦSi 和制造工艺对样品形貌的影响。随着 ΦSi 从 30 phr 增加到 80 phr，从 SANS 数据中提取的聚集体之间的相关长度从 237.0 nm 单调减少到 136.5 nm。随着 ΦSi 从 10 phr 增加到 80 phr，符合 Beaucage 模型的聚集体的平均回转半径 <Rg,agg> 从 49.2 nm 单调减小到 37.5 nm。提供 10 nm 厚度的结合橡胶作为桥接，具有最佳 ΦSi 的样品产生的形态是聚集体的半径和其间填充有聚合物基质的间隙等效于约 60 nm。