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Synthesis and Characterization of Ladder-like Poly(vinylsilsesquioxanes)State Key Laboratory of Fire Science, University of Science & Technology of China, Hefei, Anhui, 230027, China
State Key Laboratory of Fire Science, University of Science & Technology of China, Hefei, Anhui, 230027, China; tel/fax: +86 551 3601664; yuanhu{at}ustc.edu.cn;liulei@mail.ustc.edu.cn
State Key Laboratory of Fire Science, University of Science & Technology of China, Hefei, Anhui, 230027, China Ladder-like poly(vinylsilsesquioxanes)(LPVS) containing four parallel chains in the skeleton were synthesized by two steps: first, LPVS were prepared by a template sol–gel method from vinyltrichlorosilane (VTCS); then adjacent pendent vinyl groups were polymerized side by side along the LPVS chain. The resulting polymers (LPVS-2) were characterized by Fourier transform infrared, 1H NMR, 29Si NMR, thermogravimetric analysis (TGA), transmission electron microscopy, scanning electron microscopy, X-ray diffraction and elemental analysis. Experimental results reveal that both LPVS and LPVS-2 have a highly regular, ladder-like framework, and that most of the vinyl groups have taken part in the side-by-side polymerization reaction. There is no evidence that crosslinking between macromolecular chains has occurred during this process. TGA data indicate that LPVS-2 (with pendent vinyl polymerized) possesses better thermal stability than that of LPVS. For the former, no weight loss can be detected until 500°C, which is attributed to its highly regular ladder-like framework consisting of a four-parallel-chain structure.
Key Words: Thermally stable polymers • vinyl polymerization
High Performance Polymers, Vol. 18, No. 6,
919-932 (2006) |
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