Synergistically improved tracking resistance of silicone rubber with ZrP nanosheet and urethane-containing silane

The exfoliation and uniform dispersion of two-dimensional nanofillers are significantly important to improve the comprehensive properties of silicone rubber including the tracking resistance and mechanical properties. Herein, tetrabutylammonium hydroxide-intercalated zirconium phosphate (M-ZrP) and urethane-containing silane (US) were incorporated into addition-cure liquid silicone rubber (ALSR). The interaction between US and M-ZrP and the dispersion of M-ZrP in ALSR were investigated. It was found that US contributed to the exfoliation and dispersion of M-ZrP in ALSR. M-ZrP and US synergistically improved the tracking resistance of ALSR. ALSR/US/M-ZrP containing 0.1 phr M-ZrP and 1.0 phr US classed 1A4.5 level, and the ratio of electrical eroded mass was only 0.11%. The effect of M-ZrP and US on the thermal degradation behavior of ALSR and the electrical erosion residue after inclined plane test were systematically studied. It was revealed that US and Karstedt’s catalyst (Pt) synergistically promoted silicone rubber to form ceramic layer under strong arc bombardment. Besides, the exfoliated M-ZrP nanosheets in ALSR served as barrier layer and support skeleton. When subjected to arc bombardment, a compact ceramic barrier formed on the ALSR/US/M-ZrP surface, which protected the internal matrix, thus significantly improved the tracking resistance of ALSR.