Oligo（methylsilylene）-ethynylene polymer with crosslinkable ethynyl unit in the main chain was synthesized by condensation ofα,ω-dicholorooligo（methylsilane） with dilithioacetylene.The as-synthesized polymer was...Oligo（methylsilylene）-ethynylene polymer with crosslinkable ethynyl unit in the main chain was synthesized by condensation ofα,ω-dicholorooligo（methylsilane） with dilithioacetylene.The as-synthesized polymer was characterized by GPC,FT-IR and NMR.The results showed ethynyl group was successfully introduced to the polymer main chain.The ceramic yield was dramatically increased by the cross-polymerization of ethynyl group,and the excess silicon of PMS was compensated.Nearstoichiometric （C/Si=1.17） and partial crystallizationβ-SiC monoliths were obtained by pressureless pyrolysing PSPA at 1200℃in a high yield（73.6 wt%）.展开更多
Novel acetylene terminated silazane compounds,with three types of substituent,were synthesized by the aminolysis of dichlorosilane with 3-aminophenylacetylene（3-APA）.Thermal property of the compounds is studied by t...Novel acetylene terminated silazane compounds,with three types of substituent,were synthesized by the aminolysis of dichlorosilane with 3-aminophenylacetylene（3-APA）.Thermal property of the compounds is studied by thermogravimetry analysis （TGA）.It shows that the acetylene terminated silazane has high temperature resistance.The char yield at 1000℃is 77.6,81.9 and 68.7 wt%for methyl,vinyl,and phenyl substituted silazane,respectively.The pyrolysis kinetics of the silazane is investigated by non-isothermal thermogravimetric measurement.The pyrolysis undergoes three stages,which is resolved by PEAKFTT.The kinetic parameters are calculated by the Kissinger method.The role of functionalities on the thermal resistance is discussed.The vinyl-silazane exhibits higher thermal stability because of higher cross-linking density.展开更多
基金financial support of the National Science Foundation of China(No. 50903086)the Chinese Academy of Sciences
文摘Oligo（methylsilylene）-ethynylene polymer with crosslinkable ethynyl unit in the main chain was synthesized by condensation ofα,ω-dicholorooligo（methylsilane） with dilithioacetylene.The as-synthesized polymer was characterized by GPC,FT-IR and NMR.The results showed ethynyl group was successfully introduced to the polymer main chain.The ceramic yield was dramatically increased by the cross-polymerization of ethynyl group,and the excess silicon of PMS was compensated.Nearstoichiometric （C/Si=1.17） and partial crystallizationβ-SiC monoliths were obtained by pressureless pyrolysing PSPA at 1200℃in a high yield（73.6 wt%）.
文摘Novel acetylene terminated silazane compounds,with three types of substituent,were synthesized by the aminolysis of dichlorosilane with 3-aminophenylacetylene（3-APA）.Thermal property of the compounds is studied by thermogravimetry analysis （TGA）.It shows that the acetylene terminated silazane has high temperature resistance.The char yield at 1000℃is 77.6,81.9 and 68.7 wt%for methyl,vinyl,and phenyl substituted silazane,respectively.The pyrolysis kinetics of the silazane is investigated by non-isothermal thermogravimetric measurement.The pyrolysis undergoes three stages,which is resolved by PEAKFTT.The kinetic parameters are calculated by the Kissinger method.The role of functionalities on the thermal resistance is discussed.The vinyl-silazane exhibits higher thermal stability because of higher cross-linking density.
