On the characterization principles of some technically important water soluble non-ionic cellulose derivatives

Principles are developed and discussed for a detailed characterization of water soluble polymers (cellulose ethers) as to hydrodynamic and thermodynamic behaviour, molecular size in solution in solvents of varying hydrophilicity and aggregation. In particular, the application of dynamic light scattering (DLS) and size exclusion chromatography is discussed and compared with static light scattering and viscometry. Results are given for eight non-ionic cellulose ether samples concerning phase separation properties, intrinsic viscosity, Huggins' constant, weight and number average molecular weight, second virial coefficient, radius of gyration, molecular weight distribution, and hydrodynamic particle size parameters from DLS. The results are also discussed in terms of chemical properties such as degree and type of substitution and cloud point. Values of refractive index increments have been measured for all samples in the two solvents used.