Synergistic effect and mechanism of polysilazane and platinum on the thermal stability of silicone rubber

Polysilazane and platinum were adopted to enhance the thermal stability of silicone rubber. The effect and mechanism of polysilazane and platinum on enhancing thermal stability were investigated via thermogravimetry, scanning electron microscopy-energy dispersive X-ray spectrometry, thermogravimetry-Fourier transform infrared spectrometry, and Fourier transform infrared spectrometry. Remarkable synergism between polysilazane and platinum was found in enhancing thermal stability of silicone rubber. When 1.34 wt% polysilazane and 8 ppm platinum were added, the degradation temperatures were elevated. Furthermore, the thermal residues of silicone rubbers were increased from 30-45 to 66-76 wt%, and maximum degradation rates were reduced from 8.81-15.8 to 4.55-5.02 wt%/min. Besides, silicone rubber demonstrated excellent shape retention at high temperature in the presence of polysilazane and platinum. The mechanism may be that platinum cooperated with polysilazane and efficiently catalyzed radical crosslinking between polysilazane and silicone chains. As a result, a tightly crosslinked network was developed, and degradation of silicone rubber was suppressed.