ISSN:
0887-624X
Keywords:
polysiloxane
;
hexagonal columnar mesophase
;
optically active polymers
;
Chemistry
;
Polymer and Materials Science
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Chemistry and Pharmacology
Notes:
Poly[(S)-(+)-2-methylbutyl]pentylsiloxane has been synthesized by anionic ring opening polymerization of the corresponding strained cyclic trisiloxane \documentclass{article}\pagestyle{empty}\begin{document}$ (D^{\rm{MeBu, Pe}}_{3}) $\end{document} with cryptated lithium (Li+/[211]) as counterion. The polymer did not show the low and high temperature crystalline phases, that are generally found for poly(di-n-alkylsiloxane)s. Instead, the material formed a hexagonal columnar mesophase until it melted around 400°C. MAS and solution 13C- and 29Si-NMR, polarizing microscopy and WAXS indicated an unexpectedly regular chain structure. It was tentatively concluded that the steric interaction of the (S)-(+)-2-methylbutyl side chains introduces sufficient regularity of the tacticity and that the chains tend to adopt a defect helix conformation. On the other hand, DSC showed the presence of a glass transition at -113°C, indicating a high flexibility of the backbone. © 1998 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 36: 169-177, 1998
Additional Material:
7 Ill.
Type of Medium:
Electronic Resource
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