Synthesis, Thermal Degradation and Dielectric Properties of Poly[octyl(triphenylethynyl)]silane Resin

Abstract

Octyl(triphenylethynyl)silane monomer(OTPES) was synthesized with ethyl bromide, octyltrichlorosilane and phenylethylene by Grignard reaction. The molecular structure was confirmed by FTIR and NMR. The poly[octyl(triphenylethynyl)]silane resin(POTPES) was prepared by thermal polymerization and the corresponding thermal degradation behavior wasstudied by thermogravimetric analysis(TG) combining with model and model-free fitted methods. The dielectric property of resin was also studied by vector network analyzer. The results show that the melt point of OTPES was 50 °C and the processing window was over 236 °C. The resin degradation temperature of T_d5 occurred over 433 °C and the char yield was over 60% at 800 °C. Based on Kissinger, Flynn-Wall-Ozawa, Coats-Redfern, Achar, Vyazovkin-Wight and Tang methods, the reaction activity(E) was 155.51, 152.97, 150.82, 146.02, 148.38 and 148.77 kJ/mol, respectively. Dielectric properties analysis displayed that the real part(ε′) and the imaginary part(ε″) of the relative complex permittivity of POTPES was 2.5 and 0.05, respectively, and the dielectric loss tangent was between 0.03 and 0.25. The reflection loss of resin was more than −2.85 dB in all range of 1–5 mm thicknesses and 2–18 GHz frequency, which indicated that POTPES resin was a real wave-transparent resin matrix.