Anionic polymerisation of propylene oxide. Investigation of double-bond and head-to-head content by NMR spectroscopy

✍ Scribed by Ga-Er Yu; Andrew J. Masters; Frank Heatley; Colin Booth; Trevor G. Blease

• Book ID: 102939123
• Publisher: John Wiley and Sons
• Year: 1994
• Tongue: English
• Weight: 870 KB
• Volume: 195
• Category: Article
• ISSN: 1022-1352
• DOI: 10.1002/macp.1994.021950506

✦ Synopsis

Abstract

Propylene oxide was anionically polymerised in bulk at 80°C under a range of initial conditions, from zero hydroxyl content to a mole ratio of hydroxyl to potassium catalyst of 10. The double bond content of the polymers was measured by ^1^H NMR spectroscopy over a wide range of conversions, and values of the transfer constant were determined. The results were fitted to a reaction mechanism involving suppression of the transfer reaction by hydrogen bonding of hydroxyl groups to active ion pairs. The head‐to‐head content of the polymers was measured by ^13^C NMR spectroscopy. The overall proportion (approximately 4%) of ‘head‐to‐head’ reactions relative to head‐to‐tail addition was not greatly affected by suppression of the transfer reaction, since an increase in the number of head‐to‐head additions compensated the decrease in proton abstraction from methyl groups via the transfer reaction.