The mechanism of cationic copolymerization of trioxane with 1,3-dioxepane was investigated using in situ 13C NMR based on microsequence data established via PFG-HMQC and PFG-HMBC two-dimensional NMR. Kinetic profiles of pentad sequences and butylene oxide (CH2CH2CH2CH2O) counit placement were obtained. The incorporation of 1,3-dioxepane into the copolymer sequences was found to involve its initial homopolymerization followed by redistribution of counits through chain transfers, e.g. transacetalization. Unlike the copolymerization of trioxane with dioxolane, the insertion of formaldehyde into 1,3-dioxepane to form a larger acetal ring prior to substantial copolymerization does not play a significant role. For the first time, nonad sequences were observed directly by NMR analysis of the copolymer.
|Original language||English (US)|
|Number of pages||14|
|Journal||ACS Symposium Series|
|State||Published - Dec 1 2002|
ASJC Scopus subject areas
- Chemical Engineering(all)