HIGH-RESOLUTION SOLID-STATE C-13 NMR-STUDY OF ETHYLCELLULOSE FILMS

Ethylcellulose films cast from concentrated solutions of chloroform, b enzene, and carbon tetrachloride were subjected to the NMR relaxation measurements including H-1 spin-lattice relaxation time (T1H), rotatin g-frame H-1 spin-lattice relaxation time (T1rhoH), and C-13 spin-latti ce relaxation time (T1C). The values of T1rhoH for carbons in the gluc ose units of ethylcellulose were of the same order of magnitude as tho se reported for the crystalline and noncrystalline regions of ramie ce llulose. The values of T1C for unsubstituted C2, C3 carbons were small er than those for the corresponding carbons in the noncrystalline regi on of native celluloses. The T1C values for unsubstituted C2, C3, and substituted C6 carbons showed a small but definite dependence on the s olvent from which the films were cast.