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Microstructure Analysis of a CO 2 Copolymer from Styrene Oxide at the Diad Level
Author(s) -
Wu GuangPeng,
Zu YuPing,
Xu PengXiang,
Ren WeiMin,
Lu XiaoBing
Publication year - 2013
Publication title -
chemistry – an asian journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.18
H-Index - 106
eISSN - 1861-471X
pISSN - 1861-4728
DOI - 10.1002/asia.201300115
Subject(s) - diad , copolymer , styrene , microstructure , materials science , oxide , polymer chemistry , chemical engineering , composite material , polymer science , polymer , metallurgy , engineering
A large amount of interesting information on the alternating copolymerization of CO 2 with terminal epoxides has already been reported, such as the regiochemistry of epoxide ring‐opening and the stereochemistry of the carbonate unit sequence in the polymer chain. Moreover, the microstructures of CO 2 copolymers from propylene oxide and cyclohexene oxide have also been well‐studied. However, the microstructure of the CO 2 copolymer from styrene oxide (SO), an epoxide that contains an electron‐withdrawing group, has not yet been investigated. Herein, we focus on the spectroscopic assignment of the CO 2 copolymer from styrene oxide at the diad level by using three kinds of model dimer compounds, that is, T-T , H-T , and H-H . By comparing the signals in the carbonyl region, we concluded that the signals at δ =154.3, 153.8, and 153.3 ppm in the 13 C NMR spectrum of poly(styrene carbonate) were due to tail‐to‐tail, head‐to‐tail, and head‐to‐head carbonate linkages, respectively. Moreover, various isotactic and syndiotactic model compounds based on T-T , H-T , and H-H (dimers (R,R)-T-T , (S,S)-T-T , and (R,S)-T-T ; (R,R)-H-T , (S,S)-H-T , and (R,S)-H-T ; (R,R)-H-H , (S,S)-H-H , and (R,S)-H-H ) were synthesized for the further spectroscopic assignment of stereospecific poly(styrene carbonate)s. We found that the carbonate carbon signals were sensitive towards the stereocenters on adjacent styrene oxide ring‐opening units. These discoveries were found to be well‐matched to the microstructures of the stereoregular poly(styrene carbonate)s that were prepared by using a multichiral Co III ‐based catalyst system.