Polylactones, 29. Preferentially syndiotactic poly(β-(R,S)-butyrolactone) obtained by ring-opening polymerization with triphenyltin methoxide or diphenyltin dimethoxide
✍ Scribed by Hans R. Kricheldorf; Soo-Ran Lee
- Publisher
- John Wiley and Sons
- Year
- 1994
- Tongue
- English
- Weight
- 350 KB
- Volume
- 195
- Category
- Article
- ISSN
- 1022-1352
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✦ Synopsis
Abstract
Triphenyltin methoxide (Ph~3~SnOMe) and diphenyltin dimethoxide (Ph~2~Sn(OMe)~2~)‐initiated polymerizations of β‐(R,S)‐butyrolactone were conducted in bulk at 50 and 75°C. The low catalytic reactivity of the initiator prevented lower temperatures. The stereosequences of the isolated poly(β‐(R,S)‐butyrolactones) were analyzed by ^13^C NMR spectroscopy and characterized by the ratio of isotactic and syndiotactic diads (i/s‐ratios down to 0,4/1,0 were found). With Ph~3~SnOMe relatively high molecular weights (η~inh~ = 0,3 dL/g, M̄~w~ ≈ 25 000−30000) were obtained but the stereoselectivity of the polymers obtained with both Ph~3~SnOMe and Ph~2~Sn(OMe)~2~ is not higher than that with Bu~3~SnOMe (published previously). Selected poly(β‐(R,S)‐butyrolactone) samples were characterized by IR spectra, WAXS powder patterns and DSC measurements.