TY - JOUR
T1 - Synthesis, characterization, and pyrolytic conversion of a novel liquid polycarbosilane
AU - Fang, Yunhui
AU - Huang, Muhe
AU - Yu, Zhaoju
AU - Xia, Haiping
AU - Chen, Lifu
AU - Zhang, Ying
AU - Zhang, Litong
PY - 2008/10
Y1 - 2008/10
N2 - Partially ethynyl-substituted ethynylhydridopolycarbosilane (EHPCS) is prepared by Grignard coupling of chloromethyltrichlorosilane, chloromethylmethyldichlorosilane, and ethynylmagnesium bromide, followed by reduction with lithium aluminum hydride. The as-synthesized EHPCS, with a hyperbranched structure and an approximate formula of [SiH 1.35(CH3)0.37(C≡CH)0.28CH 2]n, has been characterized by GPC, FT-IR, and 1H, 13C, and 29Si NMR. The EHPCS can be cured readily in an inert atmosphere at 140°C for 6 h. Pyrolysis behavior and structure evolution of the cured EHPCS were studied by means of thermal gravimetric analysis-differential scanning calormetry, FT-IR, X-ray diffraction, and elemental analysis. It is suggested that hydrosilylation, ethynyl group polymerization, dehydrocoupling, and demethanation are involved in the cross-linking of EHPCS. The polymer-ceramic conversion is complete at 900°C, and it gives a stoichiometric and amorphous silicon carbide (SiC) with a yield of 78%. Further heating at 1200°C induces partial crystallization, forming locally ordered SiC4. The characteristic peaks of β-SiC are observable above 1600°C.
AB - Partially ethynyl-substituted ethynylhydridopolycarbosilane (EHPCS) is prepared by Grignard coupling of chloromethyltrichlorosilane, chloromethylmethyldichlorosilane, and ethynylmagnesium bromide, followed by reduction with lithium aluminum hydride. The as-synthesized EHPCS, with a hyperbranched structure and an approximate formula of [SiH 1.35(CH3)0.37(C≡CH)0.28CH 2]n, has been characterized by GPC, FT-IR, and 1H, 13C, and 29Si NMR. The EHPCS can be cured readily in an inert atmosphere at 140°C for 6 h. Pyrolysis behavior and structure evolution of the cured EHPCS were studied by means of thermal gravimetric analysis-differential scanning calormetry, FT-IR, X-ray diffraction, and elemental analysis. It is suggested that hydrosilylation, ethynyl group polymerization, dehydrocoupling, and demethanation are involved in the cross-linking of EHPCS. The polymer-ceramic conversion is complete at 900°C, and it gives a stoichiometric and amorphous silicon carbide (SiC) with a yield of 78%. Further heating at 1200°C induces partial crystallization, forming locally ordered SiC4. The characteristic peaks of β-SiC are observable above 1600°C.
UR - http://www.scopus.com/inward/record.url?scp=53349127948&partnerID=8YFLogxK
U2 - 10.1111/j.1551-2916.2008.02603.x
DO - 10.1111/j.1551-2916.2008.02603.x
M3 - 文章
AN - SCOPUS:53349127948
SN - 0002-7820
VL - 91
SP - 3298
EP - 3302
JO - Journal of the American Ceramic Society
JF - Journal of the American Ceramic Society
IS - 10
ER -