Experimental evidence for the existence of intramolecular hydrogen bonds in the water‐insoluble sodium salt of carboxyethyl cellulose solid

Kowsaka, Keisuke; Yasuda, Katsunari; Okajima, Kunihiko; Kamide, Kenji

doi:10.1002/pi.4990250206

Cited by 4 publications

References 8 publications

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Recent advances in molecuar and supermolecuar characterization of cellulose and cellulose derivatives

Kamide

Saito

1994

Macromolecular Symposia

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Rocent advances between 1985 and esrly 1993 in the following topics of the charscterisstion of molecular structure and molecular properties of cellulose and its derlvstes (CD) msde in the authors' iaboratories are briefly reviewed: (1) A theoretical basis of the sssignment of carbonyl csrbon pesks of % NMR spectrs on cellulose scotate (CAI was given. especially when the total degree of substitution ctF>, is below 3. (2) Molsr fractions of 8 kinds of unsubstituted and partiaily or fully substituted anhydroglucopyrsnose units were successfully determined for CA and sodium celiulose sulfate (NaCS). (3) The sequence distribution of substituted snd unsubstituted anhydrogiucopyranose units dong a water-soluble CA chain was evaluated. (4) C,-substitutedKe., 6-0-acetyl) CA and C2-snd C,-substituted CA were synthesized, and the full assignment of the 13C NMR spetrum of the former wss given snd a new method for evaluating the degree of substitution at C , position was proposed.( 5 ) By destructing the intramolecular hydrogen bonding, ceilulose becomes soluble in aq.sodium hydroxide. The specific supermolecular structure of aq. sodium hydroxide, dissolving mechanism, dissolved state and moiecuisr psrameters of cellulose in aq. sodium hydroxide were discussed. ( 8 ) The solubility behavior of CA with a wide range of total degree of substitution in solvents including water, acetone/water snd acetone is controlled by the distribution of substitution and the supermoiecular structure. (7) The existence of 0, -H ... 0, intramolecular hydrogen bonds in a water-insoluble celiulos* derivative with hydrophiiic substituent (NaCEC) wss confirmed by CP/MAS "C NMR snd deuterstlon IR method. At a relatively low degree of substitution the solubility of the derivative in water or aqueous aikali was mainly governed by considerable destruction of the intrsmoieclar hydrogen bonds. ( 8 ) Tho persistence length q, evaluated directly by small-angle X-ray scattering (SAXS) on CA with different tots1 degree of substitution c t h , ranging from 0.8 to 2,9 confirmed definitely the conclusion drswn before by Kamide and Saito on the moieculsr rigidity of CD, aspeciaiiy the effect of ttF>> on q. (9) C,-substituted CA shows different solubility towards dlmethyiscetamide and water at 2 0 OC, as compared with C , -and C3-subsituted CA snd C , -, C , -and C , -substitutedCA, whose ctF,, is ca. 0.6.

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Recent advances in molecuar and supermolecuar characterization of cellulose and cellulose derivatives

Kamide

Saito

1994

Macromolecular Symposia

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An explanation of the solubility behaviour of cellulose acetate in various solvents in terms of supermolecular structure formed by introduction of a substituent group into the glucopyranose unit

Okajima

Kowsaka

Kamide

1992

Polymer International

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An attempt is made to explain the solubility behaviour of cellulose derivatives with hydrophobic substituent groups towards several solvents in terms of supermolecular structure concepts, such as the degree of breakdown in intramolecular hydrogen bonds and conformational variety in the C l-O-Ck glucoside linkage, which depend on the total degree of substitution ( ( F ) ) and the distribution of substituent groups in the anhydroglucose (AHG) unit ((fk)) (k = 2, 3, and 6), and solvation.For this purpose, cellulose acetate (CA) samples with a wide range of ( ( F ) ) values were synthesized and the dependence of supermolecular structural parameters, including x,,,,(ck) (k = 3, 6) (degree of breakdown in intramolecular hydrogen bond at C, position) and Al,2(Ck) ( k = 1,6) (half value width of Ck carbon NMR peak), on ( ( F ) ) or ((fk)) was investigated. It has been shown that a considerable breakdown in 0 , -H . . . 0 5 hydrogen bond or allowance of wide variation in chain conformation around the C,-O-Ch linkage is a minimum condition necessary for CA to dissolve in solvents, irrespective of type of solvent. Water-solubility of CA is mainly governed by the supermolecular structure induced by the introduction of substituents at the C3 position and number of residual hydroxyl groups at the C, position. Acetone-solubility of CA is mainly governed by solvation of the side chain but a n intramolecular interaction between acetyl groups and ring oxygen bonds tends to hinder its solubility at high values of ( ( F ) ) . DMSO behaves as an amphoteric solvent solvating both hydroxyl and 0-acetyl groups in CA molecules.

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Solubilization and Structural Factors Governing Solubility and the Dissolved State

Kamide

2005

Cellulose and Cellulose Derivatives

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Experimental evidence for the existence of intramolecular hydrogen bonds in the water‐insoluble sodium salt of carboxyethyl cellulose solid

Cited by 4 publications

References 8 publications

Recent advances in molecuar and supermolecuar characterization of cellulose and cellulose derivatives

Recent advances in molecuar and supermolecuar characterization of cellulose and cellulose derivatives

An explanation of the solubility behaviour of cellulose acetate in various solvents in terms of supermolecular structure formed by introduction of a substituent group into the glucopyranose unit

Solubilization and Structural Factors Governing Solubility and the Dissolved State

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