C-13 NMR spectra and spin-lattice relaxation times of poly(alkyl vinyl ether)s

Abstract

13C NMR spectra of isotactic-rich poly(alkyl vinyl ether)s were measured in toluene-d8 at 110°C, with some improvements on peak separation. The 13C spin-lattice relaxation times (T1’s) for syndiotactic sequences were consistently longer than those for isotactic ones, in contrast to the case of polypropylene and polymethacrylates, in which the T1’s for isotactic sequences are longer than those for syndiotactic sequences. The nuclear Overhauser enhancement factors for the polymers of methyl and t-butyl vinyl ethers were close to the theoretical maximum. These results indicate higher flexibility of the syndiotactic sequences in poly(alkyl vinyl ether)s. © 1983 The Society of Polymer Science, Japan.