High‐resolution solid‐state 13C NMR study of ethylcellulose films

Abstract

AbstractEthylcellulose films cast from concentrated solutions of chloroform, benzene, and carbon tetrachloride were subjected to the NMR relaxation measurements including 1H spin‐lattice relaxation time (T1H), rotating‐frame 1H spin‐lattice relaxation time (T1ρH), and 13C spin‐lattice relaxation time (T1C). The values of T1ρH for carbons in the glucose units of ethyl‐cellulose were of the same order of magnitude as those reported for the crystalline and noncrystalline regions of ramie cellulose. The values of T1C for unsubstituted C2, C3 carbons were smaller than those for the corresponding carbons in the noncrystalline region of native celluloses. The T1C values for unsubstituted C2, C3, and substituted C6 carbons showed a small but definite dependence on the solvent from which the films were cast. © 1993 John Wiley & Sons, Inc.