STUDIES ON SOLUTION PROPERTIES OF CELLULOSE NITRATE (PART. 1)

Abstract

It has been widely recognized that solution properties (especially intrinsic viscosity) of cellulose nitrate cannot be accounted for by the Flory's theory, in which only the excluded volume effect is taken into consideration. It is the purpose of this paper to discuss quantitatively the deviation from the Flory's theory by considering the draining effect in additon to the volume effect.
Recently Voeks gave the relationship among the second virial coefficient A₂, intrinsic viscosity [η] and molecular weight M. This relationship has been developed to the case where the draining effect cannot be ignored. The results obtained may be expressed as: where: Φ; Universal constant, α; the expansion factor defined by Flory, f; a parameter related to the draining effect, F(X); a function of α a appearing in the Flory's theory. where: _??_a function of α, K; Flory's constant characteristics of the polymer chain, Δ; a parameter related to the draining effect.
With the aid of these equations, the constants, K_m and a, in the Mark-Houwink equation [η] =K_mM^a can be accurately calculated from the measurements of A₂, M and [η], or A₂ and M for a single polymer sample. Values thus obtained are in agreement with the experimental values.
The contributions of the two effects upon [η] are also discussed as a function of the degree of esterification (D. E.). The draining effect becomes predominant and the volume effect diminishes as D.E. increases. The exponent a in Mark-Houwink equation, therefore, increases with D. E.