A facile method for the study of slow physical and chemical processes in polymeric systems

Lundgren, Roger; Sandén, Roland; Albertsson, Ann‐Christine

doi:10.1002/app.1989.070370506

Cited by 7 publications

(3 citation statements)

References 4 publications

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“…Isothermal microcalorimetry is a well-established technique to study the stability of different chemical substances. It is widely used in pharmaceutical (Buckton, 1995;Koenigbauer, 1991) and material science (Lundgren, 1989) to obtain thermodynamic (heat of reaction) and kinetic (rate constants, rate laws) information of the appropriate investigated process. The knowledge of these parameters can be used to predict the degradation rates under storage conditions.…”

Section: Resultsmentioning

confidence: 99%

Use of Microcalorimetry in Monitoring Stability Studies. Example: Vitamin A Esters

Runge¹,

Heger²

1999

J. Agric. Food Chem.

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Vitamin A is very sensitive to chemical degradation caused by oxygen, light, heat, and other stress factors. If light and oxygen are excluded, the dominant degradation reaction for vitamin A derivatives is heat-induced formation of kitols, that is, dimers or higher oligomers. In this study vitamin A esters were used as model systems to evaluate microcalorimetry as a tool for monitoring the stability of heat sensitive substances. To obtain more knowledge about the model reaction, analytical investigations (supercritical fluid chromatography) were also performed. Because analytical and microcalorimetry data were consistent, a quantitative description of the kinetics and thermodynamics of the kitol formation reaction could be obtained. Aside from the academic motivation, this is important for practical purposes such as shelf life stability of vitamin A in feed, food, and pharmaceutical products. The vitamin A stability of a given sample can easily be predicted from the initial heat flow in a simple microcalorimetry experiment. Compared to conventional stability tests, this offers savings of money and time.

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Section: Resultsmentioning

confidence: 99%

Use of Microcalorimetry in Monitoring Stability Studies. Example: Vitamin A Esters

Runge¹,

Heger²

1999

J. Agric. Food Chem.

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“…Polymerizations, Adhesives, and Cements: Slow Reactions of Sample Components. Isothermal calorimetry has been used to study the processes involved in curing, setting, aging, and polymerization of polymers, adhesives, and cements. ,− …”

Section: Illustrative Examples Of Applicationsmentioning

confidence: 99%

Calorimetric Measurement of the Kinetics of Slow Reactions

Hansen

2000

Ind. Eng. Chem. Res.

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A brief review of the application of calorimetry to measurement of the kinetics of slow processes is presented. Processes degrading or otherwise changing the properties of materials often occur too slowly to be readily measured by conventional chemical analyses but can be measured in a relatively short period of time by heat conduction calorimetry. Instrument selection and derivation of rate laws from calorimetric data are discussed, and illustrative examples are presented.

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“…Several examples of zero-order reactions that were studied calorimetrically can be found in the literature but no extensive quantitative analysis was made because of this analytical constraint. The reactions include autocatalytic oxidation of drugs, polymer curing, oxidation of lipids, and enzymatic reactions …”

Section: Introductionmentioning

confidence: 99%

Calorimetric Determination of Rate Constants and Enthalpy Changes for Zero-Order Reactions

et al. 2012

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Calorimetry is a general method for determination of the rates of zero-order processes, but analysis of the data for the rate constant and reaction enthalpy is difficult because these occur as a product in the rate equation so evaluation of one requires knowledge of the other. Three methods for evaluation of both parameters, without prior knowledge, are illustrated with examples and compared with literature data. Method 1 requires the reaction to be studied in two buffers with different enthalpies of ionization. Method 2 is based on calculation of reaction enthalpy from group additivity functions. Method 3 applies when reaction progresses to completion. The methods are applied to the enzymatic hydrolysis of urea, the hydrolysis of acetylsalicylic acid, and the photodegradation of nifedipine, respectively.

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A facile method for the study of slow physical and chemical processes in polymeric systems

Cited by 7 publications

References 4 publications

Use of Microcalorimetry in Monitoring Stability Studies. Example: Vitamin A Esters

Use of Microcalorimetry in Monitoring Stability Studies. Example: Vitamin A Esters

Calorimetric Measurement of the Kinetics of Slow Reactions

Calorimetric Determination of Rate Constants and Enthalpy Changes for Zero-Order Reactions

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