Study Of Synthesis And Pyrolysis Of Poly(polysilane)aryne

C/C composite is widely used in aerospace field with its outstanding performance at high temperature, but in oxygen environment under the high temperature it will be oxidized easily The C/C-SiC dual matrix composite can improve the oxidation resisitence. In this paper, the poly(polysilane)aryne(PPSA) was synthesized and characterization, then the C/C-SiC dual matrix composite was maded with the poly(polysilane)aryne as the impregenent.Firstly, the dichloromethylvinyl were synthesized to polysilanes(PS) with chlorine as the end group.Then the poly(polysilane)arynes were syhthesized by the polycondensation between the polysilane and the diacetylenebenzene(DEB) grignard reagent. The structrue of poly(polysilane)aryne was characterized by FT-IR, NMR, GPC, ect. The chain structrue of poly(polysilane)aryne was characterized by1H,29Si NMR. The results show the chain length of the polysilane is betweeen2and15, and the molecule weight of poly(polysilane)aryne is between2000and5000. The resins are viscous liquid and soluble in most organic solvent.Secondly, the curing behavior of PPSAs was chacterized by DSC, and the performance of the cyred PPSAs was chacterized by DMA and TGA. The result show that the PPSAs can be thormocured and the initial and peak temperature are about250℃and320℃. The galss transition temperature of PPSAs are above440℃. The thermal decomposition temperature (Td5) are from470℃to533℃under N2and378℃to456℃under air. The residues rate are from77.9%to82.8%under nitrogen and40.4%to50.5%under air.The element content, the heat resistence and the oxidation resistence of the PPSAs were characterized by SEM, EDS, EL, IC.Finaly, the cured resins were pyrolysized in a tube furnace and the ceramic were oxidized in the tube furnace. The ceramic crystal structure of PPSAs pyrolisis were characterized by XRD and the ceramic is mainly β-SiC ceramic. The appearance, oxidation condition and element of ceramic were characterized by SEM and EDS. And the higher silicon content the sanmple has, the better oxidation resistence the sample has. The thermal oxidation stabily of PPSAs ceramic was chacterized by TGA in air. The result show that the pyrolisis residue rate is higher than98%. The ceramic show excellent oxidation resistence.