Polymer–ceramic conversion of a highly branched liquid polycarbosilane for SiC-based ceramics
| Autor: | Litong Zhang, Muhe Huang, Laifei Cheng, Zhaoju Yu, Yiguang Wang, Houbu Li, Haiping Xia, Huibin Tu |
|---|---|
| Rok vydání: | 2008 |
| Předmět: |
chemistry.chemical_classification
Thermogravimetric analysis Materials science Hydrosilylation Mechanical Engineering Analytical chemistry Infrared spectroscopy Polymer chemistry.chemical_compound Differential scanning calorimetry chemistry Polymerization Chemical engineering Mechanics of Materials visual_art visual_art.visual_art_medium General Materials Science Ceramic Fourier transform infrared spectroscopy |
| Zdroj: | Journal of Materials Science. 43:2806-2811 |
| ISSN: | 1573-4803 0022-2461 |
| DOI: | 10.1007/s10853-008-2539-8 |
| Popis: | Liquid polycarbosilane (LPCS) with a highly branched structure was characterized by fourier-transform infrared spectrometry (FT-IR) and 1H, 13C, 29Si nuclear magnetic resonance spectrometry (NMR). The LPCS was then cured and pyrolysized up to 1,600 °C under flowing argon. The structural evolution process was studied by thermogravimetric analysis and differential scanning calorimetry (TG-DSC), FT-IR, and X-ray diffraction (XRD). Hydrosilylation, dehydrocoupling, and polymerization cross-linking reactions between Si–H and C=C groups occurred at low temperatures, which mainly accounted for the high ceramic yield (70%) up to 1,400 °C. The organic groups gradually decomposed and the structure rearranged at high temperatures. The FT-IR analysis revealed that Si–CH2–Si chains, the backbone of original polymer, can be retained up to 1,200 °C. At temperatures higher than 1,200 °C, the Si–CH2–Si chains broke down and crystalline SiC began to form. The final crystalline products were β-SiC and a small amount of carbon. |
| Databáze: | OpenAIRE |
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