Synthesis and properties of poly(methylphenylsiloxane) containing methacryloyl groups

Methacryloxypropyltrimethoxysilane (MPTS) was used as the modified monomer to synthesise polymethylphenylsiloxane containing methacryloyl groups (PMPS-M) through co-hydrolysis and polycondensation with other silane monomers. The effects of MPTS on the synthesis and on the thermal and adhesive properties of PMPS-M were investigated by using Fourier-transform infrared spectroscopy (FT-IR), thermogravimetric analysis (TGA), differential thermogravimetry (DTG), scanning electron microscopy (SEM), and measurements of adhesion using a shear test. The results indicated that PMPS-M with good storage stability was synthesised successfully when the amount of MPTS was less than 8 wt%. PMPS-M had higher thermal stability than PMPS. The onset degradation temperature for PMPS-M containing 8 wt% MPTS was 518 °C, while it was 463 °C for PMPS. The improvement in thermal stability may be due to the protective effect of the methacryloyl groups, as observed under SEM. The shear strength of PMPS-M was 4.2 MPa when containing about 8 wt% MPTS, about 50% higher than that of PMPS. The shear strength of PMPS-M was also higher than that of PMPS at high temperatures.