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Digitale Medien

A segment concept in the dissolution of stereoregular isotactic polyacrylonitrile into three dinitrile solvents, CN-(CH2) n -CN (n = 1, 2, and 3), at elevated temperatures (2000)

Minagawa, M. ; Hashimoto, K. ; Shirai, H. ; [weitere]

Springer

Colloid & polymer science 278 (2000), S. 352-357

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ISSN: 1435-1536

Schlagwort(e): Key words Isotactic polyacrylonitrile ; High-temperature dissolution ; Dinitrile solvents ; Segment mobility

Quelle: Springer Online Journal Archives 1860-2000

Thema: Chemie und Pharmazie , Maschinenbau

Notizen: Abstract The dependence of the dissolution temperature (T sol) of isotactic polyacrylonitrile (PAN) on tacticity was studied for three dinitrile solvents. A linear relationship was obtained in the inverse plots of the tacticity dependence of the T sol of PAN. A phenomenological analogy between the tacticity dependence of the T sol of isotactic PAN and the molecular-weight dependence of the glass-transition temperature of amorphous polystyrene is discussed from a thermodynamic point of view. The linear relationships in both phenomena are explained in terms of a common mechanism: a breakdown of thermodynamic competition, enthalpy, and entropy through the segment mobility. The significance of segment concept and molecular mobility at elevated temperatures are discussed.

Materialart: Digitale Medien

URL: http://dx.doi.org/10.1007/s003960050524

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Digitale Medien

Pulse response in an immobilized-enzyme column: Theoretical method for predicting elution curves (1980)

Adachi, S. ; Hashimoto, K. ; Matsuno, R. ; [weitere]

New York, NY [u.a.] : Wiley-Blackwell

Biotechnology and Bioengineering 22 (1980), S. 779-797

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Details

ISSN: 0006-3592

Schlagwort(e): Chemistry ; Biochemistry and Biotechnology

Quelle: Wiley InterScience Backfile Collection 1832-2000

Thema: Biologie , Werkstoffwissenschaften, Fertigungsverfahren, Fertigung

Notizen: A theoretical method for predicting the elution profile of a pulse response in an immobilized-enzyme column is proposed. The method is based on a mass balance model, which is extensively used in gel chromatography. To test the method, a pulse of sucrose solution was applied to a column of spherical acrylamide gel in which was entrapped invertase from yeast, and it was eluted with 0.05M acetate buffer at pH 5.0. The elution curves of the substrate and the product were in fairly good agreement with the theoretically calculated ones. The method was extended to the system of reversible as well consecutive reactions.

Zusätzliches Material: 9 Ill.