| Aryl-acetylene resins possess the characteristics of ease of processing, no volatility during cure and high residue after pyrolysis, compared with current thermosetting resins, which are widely used in the field of aviation. Introduction of silicon, boron, nitrogen, germanium and phosphorus into arylacetylene could improve the high-temperature resistance and thermo-oxidative stability of materials. In this article, several aryl-acetylenes containing silicon, nitrogen, boron were prepared by easy-operating synthesis reactions. These polymers obtained contained aryl-acetylene group in their structures, which could be cured and molded by means of the cross-linking reactions among arylacetylene groups. These polymers have potential of high-temperature resistant structure parts, ceramic precursors and matrix materials of composites. In this paper, composites were compared based on two resins and properties of mechanical, dielectric, resistance to high-temperature and moisture of composites were studied to meet the requirements of the field of aviation for high-temperature resistant materials.Firstly, five kinds of (ethynylphenyl-amino)silane (EAS):methly-di(m-ethynylphenyl-amino)silane (MEAS), dimethly-di(m-ethynylphenyl-amino)silane (DMEAS), methly-tri(m-ethynylphenyl-amino)silane(MTEAS), phenyl-tri(m-ethynylphenyl-amino)silane (PTEAS) and tetra(m-ethynylphenyl-amino)silane (TEAS), were prepared by the aminolysis reaction between chlorosilanes and m-aminophenylacetylene. The resulting resins were characterized by IR, MS,1H-NMR, and 13C-NMR. Due to the high activity of terminal acetylene groups in the molecule, EAS occurs cross-linking reactions at lower temperatures, which was benefit to its forming process and application. In this article, the curing reaction kinetics and the curing mechanism of EAS were studied. The high-temperature resistance and sintered properties were studied using TGA. The results showed that EAS thermosets possessed excellent high-temperature resistance. Td5 of TEAS thermoset in nitrogen was 607℃and the weight residual at 900℃was 86.0%. After sintered at 1450℃in argon, MEAS thermoset derived free carbon, (3-SiC andα-Si3N4. TEAS was modified by di (N-m-acetylene-phenylphthalimide) ether (DAIE) which containing acetylene groups in the molecule to prepare glass fiber reinforced polymer composites. The obtained composites possessed lower curing temperatures, good processing and mechanical properties when the weight ratio of TEAS to DAIE was 5:3. Flexural strength and interlaminar shear strength of the composites were 385.7 MPa and 37.5 MPa respectively.Secondly, making use of the reactivity of the Si-H bond with B-OH groups with nickel power as the catalyzer. phenyldi[(methyldiphenylethynyl)-silcon-oxygen]borane(B-MDPES) resin was prepared based on MDPES and phenylboronic acid. Si-O-B unit was intruduced successfully into the molecular structure of silicon-containing arylacetylene polymers. In this article, we studied the curing mechanisms of B-MDPES resin and the heat resistance and thermo-oxidation properties of B-MDPES thermoset. The purpose of this research was to develop boron-containing arylacetylene polymers with improved heat resistance and thermo oxidation properties. TGA data showed that B-MDPES thermoset possessed outstanding high-temperature resistance in nitrogen and was sensitive to oxygen when heated to a temperature higher than 580℃. Td5 in nitrogen and air were 681.4℃and 578.4℃. the char yields at 900℃were of 91.7% and 42.6% in nitrogen and air respectively, higher clearly than that of MDPES thermoset. The thermal decomposition processes of B-MDPES thermoset in inert atmosphere were detected using Pyrolysis-Gas Chromatography-Mass. Benzene was the main degradated compound, accounting for 49.27%. Composite was compared based on B-MDPES modified with DAIE and properties of mechanical, dielectric, resistance to high-temperature and moisture of composites were studied.Thirdly, based on phenylboronic acid, phenyltrichlorosilane, the lithium phenylacetylide poly (phenylethynylsilyl-oxide-borane) (PSOB) was prepared with Si-O-B and ph-C=C-groups contained in repeated units. Tri[diphenylphenylethynylsilyl-oxide]-borane (TSOB) was prepared based on diphenyl-dichlorosilane, boric acid, phenyl-acetylene and n-butyl lithium. The resulting products were characterized by IR,'H-NMR,13C-NMR,29Si-NMR and 11B-NMR. The temperatures of 5% weight loss (Tds) of PSOB thermoset in nitrogen and air were 573℃and 565℃, the char yields at 900℃were of 87.6% and 65.0% in nitrogen and air respectively. The decomposition process of PSOB thermoset at 750℃in argon was detected using pyrolysis-GC-MS. The results showed that benzene was the main degradated product with the content of 77.1%. The weight residual yields of PSOB and TSOB thermoset after ceramic treatment at 1450℃were 47.6% and 49.7% respectively, which were higher than that of PTPES thermoset (20.1%), which showed that the introduction of boron element was benefit to the ceramic reaction of materials. |
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