On the partially free draining effect in the intrinsic viscosity and sedimentation coefficient of cellulose nitrate solution

The partially free draining effect on intrinsic viscosity, sedimentation and diffusion constant was evaluated for cellulose nitrate solution. The methods used in this study involve the analysis of (a) parameters in the K UHN ‐M ARK ‐H OUWINK ‐S AKURADA equation, (b) intrinsic viscosity [η] and concentration dependence of sedimentation coefficient k s , (c) [η], k s , molecular weight M, and second virial coefficient A 2 , (d) molecular weight dependence of sedimentation constant and the exponent a in the K UHN ‐M ARK ‐H OUWINK ‐S AKURADA equation, (e) a and molecular weight dependence of diffusion constant, (f) a and dependence of [η] on radius of gyration of a polymer chain R, (g) a and molecular weight dependence of R, (h) [η], M, R, and the linear expansion factor α, (i) [η], M, and A 2 . Draining parameters thus obtained, such as X, ν(X), and Δ which were defined in the theories of K URATA ‐Y AMAKAWA and K AWAI ‐K AMIDE , are compared with those in literature. Although the methods used here have been derived from different theoretical bases using different approximations, ν(X) was evaluated as 0.3 ± 0.1 for cellulose nitrate with nitrogen content of 12 to 14%, irrespectively of the method used. This indicates that the draining effect can not be ignored, in other words, the intrinsic viscosity and sedimentation data can not be interpreted reasonably by the excluded volume theories, without taking into account the draining effect.