Significant improvement of urethane-containing silane on the tracking and erosion resistance of silicone rubber/silica nanocomposite by enhancing the interfacial effect

Yajun Zhang, Xingrong Zeng*, Xuejun Lai*, Hongqiang Li, Xiaoyi Huang

Abstract:  Rapid crosslinking of silicone chains on the nanosilica surface during arc discharge is proposed as an efficient strategy to improve the tracking and erosion resistance of silicone rubber. Urethane-containing silane (URS) was synthesized by using (3-isocyanatopropyl) triethoxysilane, isopropyl alcohol and allyl alcohol via nucleophilic addition and trans-etherification. The suppression effect and mechanism of URS on the tracking and erosion of addition-cure liquid silicone rubber/silica (ALSR/SiO2) nanocomposite were investigated. It was found that URS could significantly enhance the tracking and erosion resistance of ALSR/SiO2. When only 2.5 phr URS was added, all the ALSR/SiO2/URS specimens passed the inclined plane test at 4.5 kV and the erosion rate decreased from 3.44% to 0.25%. This might be because URS tightly constrained silicone chains on the SiO2 surface by strong hydrogen-bonding interactions. During arc discharge, URS at the interphase enhanced the catalytic activity of platinum compound to promote the radical crosslinking of silicone chains absorbed on the SiO2 surface. Hence, a compact and intact ceramic layer was quickly formed on the ALSR surface and protected the underlying materials from further arc ablation. Our finding provides a new method and theoretical basis for the design, preparation and application of the novel high-performance polymer insulating material.

  论文链接：https://doi.org/10.1016/j.polymertesting.2018.05.005