MOLECULAR INHOMOGENEITY OF CARBOXYMETHYL CELLULOSE FROM FRACTIONATIONAND SEDIMENTATION-VELOCITY DATA

The inhomogeneity of mono-substituted carboxymethyl cellulose samples as to the degree of substitution and molecular weights has been charac terized with the aid of fractionation and velocity ultracentrifugation . It was shown that the former is not high, whereas the latter is cons iderable : the inhomogeneity parameter M2/M(W) for different samples v aried from 1.8 to 3.5. These values have been obtained by the method o f moments with linear approximations which was shown to be applicable to a reliable characterization of polydispersity of carboxymethyl cell ulose samples. The possibilities offered by the velocity sedimentation method for characterization of carboxymethyl cellulose in solutions i n different solvents are discussed.