Estimation of Unperturbed Chain Dimensions of Cellulose, Amlose, and Their Derivatives in Solution from Frictional Coefficient Data

Abstract

ABSTRACT:An attempt was made to establish a method (method 2J) for estimating the unperturbed chain dimensions A [=6 112 (<S 2 ) 0/M) 112 • <S 2 ) / 12 , unperturbed radius of gyration; M, molecular weight] of polymers from the frictional coefficient f; in the case when the polymer chains are non-Gaussian and the draining effect cannot be ignored. The following equation was derived:f;/r;o =61/2 KpK 0 o.5 M0.5+0.5a2+ap(l +0.0144 where r;0 is the viscosity of the solvent, B is a long-range interaction parameter, Kp and aP are parameters in the equation of the molecular weight dependence of the Flory parameter Pas defined by P=KpMaP, Ko and a2 are parameters in the relation: <S 2 ) 0/M=K0Ma2. By putting a2 =ap=0, the above equation reduces to practically the same equation as that obtained by Cowie and Bywater (method 21). These two methods (method 21 and 21) were applied to literature data on cellulose, cellulose diacetate, cellulose tricarbanilate, ethylhydroxyethyl cellulose, and amylose triacetate. Method 21 meets with great success in elucidating the A value for these polymers. The A value as determined by method 21 is only some 50 % of the most reliable value. (1)' KEY WORDSIn a previous paper 1 we have determined the most reliable short-range parameter A [ =6 112 ( (S 2 ) 0/ M)1 12 • (S 2 ) 0 112 , radius of gyration at unperturbed state; M, molecular weight] for cellulose, amylose, and their derivatives by using thermodynamic and viscometric approaches. It has been confirmed in this paper that polymer chains are non-Gaussian and the contribution of the draining effect to hydrodynamic properties, including limiting viscosity number [77], and sedimentation and diffusion coefficients at infinite dilution, s0 and D 0 , can never be ignored. When these effects are reasonably taken into account in the methods for estimating A, almost the same A values are obtainable for any given polymer-solvent pair.

Nuclear Magnetic Resonance Study of Thermodynamic Interaction between Cellulose Acetate and Solvent

“…This phenomenon is very noticeable in polar polymers. The unusually large solvent dependence of the unperturbed chain dimensions has already been reported for cellulose, amylose, and their derivatives by Kamide et al,[5][6][7][8][9] who analyzed literature data available. On the other hand, the existence of a hydrogen bond between the 0-acetyl group in the CA molecule and halogenated hydrocarbons 10 • 11 and the interaction between the 0-acetyl group and aniline or acidic solvents has been proposed 12 on the basis of infrared spectroscopic observations.…”

Limiting viscosity number and sedimentation coefficient of solutions of cellulose acetates

“…( 1 7 Both X and E should be determined from the measurement of a and a, by using Eqs. (13) and (14), when the a, value is estimated by other methods. By using a = 0,616 and a, = 0,39 for CA (D.S.…”