The preparation of fluorine-containing polysiloxane low-melting glass and its effect on the tracking resistance and thermostability of addition-cure liquid silicone rubber

Abstract

Fluorine-containing polysiloxane low-melting glass (FPLMG) was prepared by the hydrolysis-condensation of tridecafluorooctyltriethoxysilane (FAS), vinyltriethoxysilane (ViTES) and phenyltriethoxysilane (PhTES). FPLMG was characterized by Fourier transform infrared spectrometry (FTIR), nuclear magnetic resonance spectrometry (1H-NMR), X-ray diffraction (XRD), gel permeation chromatography (GPC), differential scanning calorimetry (DSC) and thermogravimetric analysis (TG). The effect of FPLMG with different FAS content on the mechanical and hydrophobic properties, tracking resistance and thermal stability of addition-cure liquid silicone rubber (ALSR) was investigated. The results showed that FPLMG had an amorphous ladder-like structure. The molecular weight and glass transition temperature of FPLMG increased with more addition of FAS. The tracking resistance and hydrophobicity of ALSR could be significantly enhanced by FPLMG. FPLMG formed a "glassy layer" on the surface of ALSR, which effectively improved the thermal stability of silicone rubber. Therefore, the tracking resistance of ALSR was enhanced because of the improvement of hydrophobicity and thermal stability of ALSR by FPLMG.