Treatment of the effect of excluded volume and deduction of unperturbed dimensions of polymer chains. Configurational parameters for cellulose derivatives

Methods currently used for deducing unperturbed dimensions of polymer chains from intrinsic viscosities are examined and the hazards of linear extrapolation of plots of [η]2/3/M1/3 against either M2/3/[η]1/3 or M/[η] for this purpose are pointed out. Applications of this procedure to cellulose derivatives have led to erroneous results. Proper interpretation of newer data substantiated earlier conclusions to the effect that these chains tend to be more highly extended than those of other polymers, and that their unperturbed dimensions vary markedly from one solvent medium to another.