The Partially Free Draining Effect and Unperturbed Chain Dimensions of Cellulose, Amylose, and their Derivatives

Abstract

In order to estimate the unperturbed chain dimensions of cellulose, amylose and their derivatives, the literature data available for fourteen polymers have been analyzed systematically. The draining parameter X defined in Kurata-Yamakawa theory was evaluated by various methods and was found to be less than 2 in most instances, regardless of the methods employed. The polymers exhibited often a significant non-gaussian nature expressed by a negative value of a2 =d In ((S 2 ) 0/M)/d In M, where (S 2 )a1 12 is the radius of gyration of a polymer chain in the unperturbed state and M is the molecular weight. Flory's viscosity parameter </J always showed a positive M dependence as described by a,p=d In </J/d In M>O. The latter finding is compatible with low X values. Two new methods for estimating A(=6 ((S 2 ) 0/M) 112 ) in the case of a2=\=0 and a,p=\=0 were proposed as generalization of the Baumann plot and the Stockmayer-Fixman (SF) plot. The same A values were obtained by thermodynamic and hydrodynamic approaches. The original SF plot proved unsuccessful and underestimated A by about 501/o. Cellulose, amylose, and their derivatives have large unperturbed chain dimensions and their expansion factors are not much larger than unity even in good solvents.

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.…”

Thermodynamic and Hydrodynamic Properties of Cellulose Diacetate–Dimethylacetamide Solutions

“…Thus, methods 2E and 2F underestimate A significantly, and the most probable A value should be the average (1.98 x 10-8 em) of those determined by methods 2B, 2C, and 2G. 4 The dependence of A and a on the dielectric constant e of the solvent is illustrated in Figure 6. Both A and a increase with increasing e, which confirms that the CDA chain becomes less flexible when dissolved in a more polar solvent.…”

“…The unperturbed chain dimensions A ( =(<R 2 ) 0 / M) 1 ' 2 ; <R 2 ) 0 , the mean-square end-to-end distance of the chain in the unperturbed state) were estimated by using methods 2B, 2C, 2E, 2F, and 2G, proposed in a previous paper. 4 Equations basic to these methods are as follows:…”

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

“…In 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.…”

“…By use of eq 5, we can estimate the X value from p and a5 • The latter can be evaluated from a penetration function <jJ in the manner described before. 1 This method (method lG) is analogous to method lA in the previous paper, which is based on:…”