Determination of reactivity ratios for the anionic copolymerization of ethylene oxide and propylene oxide in bulk

✍ Scribed by Frank Heatley; Ga-er Yu; Colin Booth; Trevor G. Blease

• Publisher: Elsevier Science
• Year: 1991
• Tongue: English
• Weight: 570 KB
• Volume: 27
• Category: Article
• ISSN: 0014-3057
• DOI: 10.1016/0014-3057(91)90138-e

✦ Synopsis

Reactivity ratios have been determined for the anionic copolymerization of ethylene oxide and propylene oxide in bulk over the temperature range 0-80°C. The ratios were obtained by two methods, the first using the variation of copolymer composition with monomer feed composition according to the May~Lewis equation, and the second using the triad sequence distribution derived from t3C-NMR spectra. In both methods, the ratios were obtained by a computer search for the values giving the best fit between simulated and experimental data. The program took composition drift into account by numerical simulation of the copolymerization as a series of small steps, the feed composition being adjusted after each step. The reactivity ratios were independent of temperature within experimental error, with average values r E = 2.8 -}-0.6 and re = 0.25 + 0.07 from the Lewis-Mayo equation, and r E = 3.1 + 0.4 and rp = 0.30 + 0.04 from the triad distribution.