Poly[(S)-(+)-2-methylbutyl]pentylsiloxane

✍ Scribed by Aart Molenberg; Daniela Michalke; Martin Möller; Thomas Pieper

• Book ID: 101272082
• Publisher: John Wiley and Sons
• Year: 1998
• Tongue: English
• Weight: 295 KB
• Volume: 36
• Category: Article
• ISSN: 0887-624X
• DOI: 10.1002/(sici)1099-0518(19980115)36:1<169::aid-pola21>3.0.co;2-g

✦ Synopsis

Poly[(S)-(/)-2-methylbutyl]pentylsiloxane has been synthesized by anionic ring opening polymerization of the corresponding strained cyclic trisiloxane (D MeBu,Pe 3

) 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(din-alkylsiloxane)s. Instead, the material formed a hexagonal columnar mesophase until it melted around 400ЊC. MAS and solution 13 C-and 29 Si-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 0113ЊC, indicating a high flexibility of the backbone.