Molecular Weight and Intrinsic Viscosity of Nitric Triesters of Corn Starches and Dextrins

Oligosaccharidesof DP 3-10 were evaluated for their properties of density, refraetive index, viscosity, optical rotation, reducing power, and infrared absorption characteristics.Tables of data were developed giving the expected values of each property for each oligosaecharide.As expected, density, refractive index, viscosity, optical rotation, and reducing power were related to the molecular weight of the sugars. The degree of the effect of molecular weight on each of these properties was established.

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“…The linear relationship between log [v] and log DP reported by Caesar et al (1947) seems to be substantiated by this work.…”

Section: Resultssupporting

confidence: 83%

Isolation and Evaluation of the Saccharide Components of Starch Hydrolysates. II. Evaluation

Hoover¹,

Nelson²,

Milner³

et al. 1965

Journal of Food Science

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“…The availability of two starch fractions, namely, amylose and amylopectin, siinplified the study of two considerably different polyineric carbohydrate nitrates (2,8,9,24). Thus, recently the Will and Lenze method for the preparation of whole-starch nitrate (23) was revived once again by Ashford, Evans, and Hibbert (2) for nitrating the amylose and the amylopectin fractions of the starch granule.…”

mentioning

confidence: 99%

Stabilization of Polymeric Carbohydrate Nitrates From Studies on Starch, Amylose, Amylopectin, and Glycogen

Mustafa¹,

Dawoud²,

El-Shourbani³

1962

Can. J. Chem.

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Whole starch, an~ylose, amylopectin, and glycogen (polymeric carbohydrates of the a-D-glycosidic linkage type) were nitrated by nitric acid in the presence of phosphoric anhydride and stability properties of the nitrated products were studied. Crude amylose nitrate is more stable than a~nylopectin nitrate and the latter is less stable than the whole-starch nitrate a s judged by the Bergmann-Junk test. The stability of glycogen nitrate is closely similar to that of amylopectin nitrate.Appreciable stabilization of the crude nitrates mas brought about by boiling with slightly allcaline water for long periods (60-70 hours). All stabilized samples were found to possess closely si~uilar stability properties. The Bergmann-Junk values of all examined nitrates ranged from 2.2 to 1.7 mg of nitrogen per gram sample; the latter value seems to represent the maximum stabilization which could be attained for the polymeric carbohydrate nitrates of the a-D-glycosidic linkage type. In the case of cellulose nitrate (6-D-glycosidic linkage type) Bergmann-Junk values of 1 to 1.25 mg of nitrogen were obtained.

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Isopiestic method for determining molecular weights of polymers

Parrette¹

1955

J. Polym. Sci.

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The methods generally used for determination of the molecular weight of polymers usually cannot be used for molecular weights between 1000 and 30,000. This is the range most suitable for determination by the isopiestic method, whereby the molecular weight is measured by comparing the vapor pressure of the polymer solution with that of a solution containing a reference solute. The isopiestic principle can be adapted to polymers if the high degree of dependence of solute and solvent activities upon concentration can be evaluated. This is easily accomplished by plotting the reciprocal of the apparent molecular weight against the concentration and making an extrapolation to infinite dilution. Certain modifications of the conventional isopiestic techniques are necessary in order to accelerate the attainment of isopiestic equilibrium and to eliminate water from the solutions. Isopiestic equilibrium is readily attained if a proper combination of solvent and temperature is chosen, and if the solutions are agitated adequately. Water may be removed by the use of a drying agent in the solutions, although the drying agent causes minor errors which are difficult to correct. Results obtained with the isopiestic method show that it is reliable for molecular weights up to 40,000. The accuracy decreases rapidly with higher molecular weights.

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Molecular Weight and Intrinsic Viscosity of Nitric Triesters of Corn Starches and Dextrins

Cited by 18 publications

References 1 publication

Isolation and Evaluation of the Saccharide Components of Starch Hydrolysates. II. Evaluation

Isolation and Evaluation of the Saccharide Components of Starch Hydrolysates. II. Evaluation

Stabilization of Polymeric Carbohydrate Nitrates From Studies on Starch, Amylose, Amylopectin, and Glycogen

Isopiestic method for determining molecular weights of polymers

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