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Synthesis, characterization, and properties of silylene–acetylene preceramic polymers
Author(s) -
Ye Li,
Han Weijian,
Zhang Ruilin,
Hu Jidong,
Zhao Tong
Publication year - 2008
Publication title -
journal of applied polymer science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.575
H-Index - 166
eISSN - 1097-4628
pISSN - 0021-8995
DOI - 10.1002/app.28996
Subject(s) - thermogravimetric analysis , thermal stability , silylene , materials science , differential scanning calorimetry , magic angle spinning , polymer chemistry , ceramic , condensation polymer , polymer , chemical engineering , chemistry , organic chemistry , nuclear magnetic resonance spectroscopy , composite material , silicon , physics , engineering , metallurgy , thermodynamics
Abstract A series of silylene–acetylene preceramic polymers 3a–e were synthesized by polycondensation reaction of dilithioacetylene with dichlorosilane (H 2 SiCl 2 ) or/and methyldichlorosilane (MeSiHCl 2 ). Their structures were confirmed by infrared spectra (IR), and 1 H and 29 Si NMR spectroscopies. Differential scanning calorimetry (DSC) diagrams show exotherms centered at 200 to 233°C temperature range, attributed to crosslinking reaction of the acetylene and SiH groups. After thermal treatment, the obtained thermosets 4a–e possess excellent thermal stability. Thermogravimetric analysis (TGA) under nitrogen show the T d 5 s (temperature of 5% weight loss) for all the thermosets are above 600°C, and the overall char yields are between 95.62% and 89.67% at 900°C. After pyrolysis at 1200°C, the obtained ceramic residues 5a–e exhibit good thermo‐oxidative stability with final weight retention between 98.76% and 91.66% at 900°C under air. In particular, perhydroploy(silylene)ethynylene 3a , which has the highest Si/C ratio in silylene–acetylene polymers, has the highest char yield, and the derived ceramic material 5a displays the best thermo‐oxidative stability. Based on Scanning electron microscopy and its associated energy‐dispersive X‐ray microanalysis (SEM EDX) and 13 C magic angle spinning nuclear magnetic resonance (MAS NMR) analysis, ceramic 5a contains the highest SiC content. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008