The configuration of cellulose dissolved in iron‐sodiumtartrate

Viscosity and light scattering data on 10 cellulose samples in the iron‐sodiumtartrate solvent (FeTNa) are presented and examined in the light of the FLORY‐FOX treatment of dilute solution properties. The FLORY factor, Φ, is found to increase with mol. wt. approaching a constant value when M̄ w exceeds 500 000. Good linear correlation with the data is found for [η] M̄ w as a function of R . Functions proposed for evaluation of the unperturbed dimensions by means of intrinsic viscosity and mol. wt. have been tested on the present data. Good linear fit is obtained for six of these from medium to high molecular weight range. From the slope of the linear part of the STOCKMAYER‐FIXMAN plot, the second virial coefficient is calculated, according to KRIGBAUM, which is in good agreement with the experimental values obtained by light scattering. It is suggested that a decrease of flexibility with decreasing mol. wt. could result from immobilization of monomer‐monomer bonds in the cellulose‐iron complex formed on dissolution.