Effect and mechanism of polysilazane and platinum on tracking and erosion resistance of silicone rubber

Abstract

Polysilazane (PSiN) and platinum (Pt) were used to enhance the tracking and erosion resistance of silicone rubber. The suppression effects of PSiN and Pt on tracking and erosion were investigated using an inclined plane test (IPT), thermogravimetry, thermogravimetry-Fourier transform infrared spectrometry, scanning electron microscopy and laser Raman spectroscopy. It was determined that the addition of 1.8–2.4 part per hundred parts of rubber (phr) of PSiN and 8 ppm of Pt significantly enhanced the tracking and erosion resistance of silicone rubber, whereby the test specimens passed a 4.5 kV IPT with a low eroded mass and undamaged surfaces. This was attributed to the synergistic effect of PSiN and Pt on silicone chains. At high temperatures and produced by arc discharge, PSiN/Pt-catalysed radical crosslinking suppressed the degradation of silicone chains. Furthermore, the formation of a tightly crosslinked network protected the inner materials from arc ablation. In addition, carbon deposition was prevented by PSiN/Pt, making it harder for tracking to develop.