Synthesis, Cure Kinetics And Properties Of Triphenylthynylsilane

Silicon-containing arylacetylene resin possesses high temperature resistance, excellent dielectric properties and other functional performances. It has become a hot spot of high performance resin matrix in recent years, and was widely used in the fields of aerospace. A kind of silicon-containing arylacetylene resin, i.e. triphenylthynylsilane, was synthesized in this article to explore its properties of cure kinetic, catalytic graphitization, and wave-transparent. All these studies can help to provide theoretical and experimental foundation for the industrialization of silicon-containing arylacetylene resin.At first, two kinds of triphenylthynylsilane monomer namely, Methyl-tri(phenylethynyl)silane(MTPES) and propyl-tri(phenylethynyl)silane(PTPES) were prepared by Grignard reaction in this paper. Their molecular structure was characterized by Fourier transform infrared spectroscopy (FT-IR), nuclear magnetic resonance (1H-NMR,13C-NMR, and 29Si-NMR). Then the cure behavior and non-isothermal cure kinetics of MTPES and PTPES were discussed. What’s more, the catalytic graphitization properties of corresponding cured resin (PMTPES and PPTPES) were also studied. At last, a new kind of composite material (SiO2/PPTPES) was synthesized by using PPTPES resin as matrix and porous SiO2 as reinforcing material. The major works and conclusions are listed as following:(1) The cure schedule of MTPES and PTPES was obtained by non-isothermal rheological curve and non-isothermal DSC curves at different heating rates applying with extrapolation method, and was further verified by Fourier transform infrared spectroscopy (FT-IR). Results showed the melting point and gelation temperature of MTPES were 130℃ and 330℃, respectively. While the corresponding value of PTPES is 75℃ and 333℃. The processing window of PTPES (258℃) were much larger than that of MTPES (200℃). Therefore, PTPES was expected to be a good matrix for composites because of its excellent processability.(2) Four thermodynamic analysis methods, i.e. Kissinger、Owaza、 Flynn-Wall-Ozawa and Friedman methods, were adopted to study the cure kinetic of MTPES and PTPES. The result showed that the autocatalytic kinetic model was found to be the best description of the curing process of MTPES and PTPES. The activation energy of MTPES is 112.58kJ/mol, and the reaction order n, m of MTPES is 1.20 and 0.56, while the corresponding value of PTPES is 123.96kJ/mol,1.43 and 0.36, respectively.(3) The catalytic graphitization behavior of two kinds of Triphenylthynylsilane resin (PMTPES and PPTPES) were characterized by the means of X-ray diffraction spectra (XRD) and laser Raman spectroscopy (LR), and the effect of heat treatment temperature and content of catalyst on catalytic graphitization behavior was discussed. Results showed that the graphitic carbon of PMTPES and PPTPES was formed by carbide-decomposition mechanism. However, the graphitization effect of PMTPES is superior to that of PPTPES under the same condition. To PMTPES resin, the best graphitization effect can acquired when heat treatment temperature and content of iron is 1650℃ and 6%, respectively. While to PPTPES resin, the corresponding value is 1650℃ and 15%, respectively.(4) Using teraethylorthosilicate (TEOS) as silica source, ordered macroporous SiO2 was prepared in template-based sol-gel process. The scanning electron microscope (SEM) images of macroporous SiO2 indicated the pore was uniform and pore size was about 200nm. Then the SiO2/PPTPES composite was synthesized with PTPES and macroporous SiO2 in the dip-curing process, and was characterized by the means of thermogravimetric (TG) analysis and vector network analyzer. It was shown that the temperature when mass loss is 5%(Tds) of composite is 476℃, and the corresponding temperature of maximum decomposition rate is 520℃, and the carbon residue rate at 800℃ was 78%. In addition, results showed that dielectric constant and dielectric loss tangent value of composite in the frequency range of 2-18 GHz was 2.40～2.72 and 0.019～0.243 respectively, which met the need of wave-transparent material. Therefore, this composite may be a good candidate for wave-transparent material with high temperature resistance.