3 - Molecular Properties of Cellulose and cellulose derivatives

Abstract

The molecular properties of cellulose and cellulose derivatives are determined by various methods, such as sample preparation, fractionation, membrane osmometry, vapor pressure osmometry, light scattering, viscometry, sedimentation velocity, and adiabatic compressibility. The cellulose derivatives are basically derived by the nuclear magnetic resonance study of thermodynamic interaction, small angle X-ray scattering, Mark-Houwink-Sakurada equations, the molecular weight dependence of radius gyration, and the molecular weight dependence of sedimentation and diffusion coefficients. The Flory's viscosity parameter and partial draining effect, unperturbed chain dimensions, and solvation are also helpful in the determination of a number of the solvated molecules per repeated unit. The effect of solvent nature and total degree of substitution is established to determine the correlation between the molecular properties and the degree of solvation by measuring the chemical shifts and adiabatic compressibility using an ultrasonic interferometer. Moreover, the persistence length, the temperature dependence of limiting viscosity number and the radius of gyration, phase separation, and cellulose liquid crystal methods are also used for the determination of derivatives. Therefore, the characteristic feature of the dilute solutions of cellulose and its derivatives can be reasonably and consistently explained by solvation.