Add time:08/14/2019         Source:sciencedirect.com

13C nuclear magnetic resonance (n.m.r.) spectroscopy was used for the determination of the sequence distribution in vinyl alcohol-vinyl propionate (VAL-VP) copolymers prepared by two different methods: by partial alkaline hydrolysis of poly(vinyl propionate) and by partial esterification of poly(vinyl alcohol). The 13C n.m.r. spectra of the methylene carbons in the main chain show three split peaks, whose intensities change with copolymer composition. These peaks can be assigned to the three dyad sequences. The results obtained show that vinyl propionate units have an alternating tendency in VAL-VP copolymers prepared by esterification and a block distribution in VAL-VP copolymers prepared by hydrolysis. The Tg values of VAL-VP copolymers prepared by the two different methods are influenced by both the overall copolymer composition and the monomer sequence distribution.

We also recommend Trading Suppliers and Manufacturers of Vinyl propionate (cas 105-38-4). Pls Click Website Link as below: cas 105-38-4 suppliers