Synthesis and characterization of alternating silane copolymers: (Me2Si−R2Si−Me2Si) n
Tóm tắt
Bimodal molecular weight distributions of alternating copolymers of the type (Me2Si−R2Si−SiMe2)
n
, where R=hexyl and butyl, were obtained by polymerization of BrSiMe2−R2Si−Me2SiBr, using the Wurtz coupling method. Analysis of the samples by pyrolysis GC MS and solution29Si NMR indicated that some randomization occurred, due to cleavage of the original Si−Si bonds in the monomer. The extent of randomization was significantly greater in the high molecular weight fractions. Based on the nature of the rings from the py MGC/MS traces and the number on nonads found in the29Si spectra, two types of randomization processes have been proposed, involving backbiting followed by (1) ring expulsion or (2) redistribution.
Tài liệu tham khảo
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