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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. ; [et al.]

Springer

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

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ISSN: 1435-1536

Keywords: Key words Isotactic polyacrylonitrile ; High-temperature dissolution ; Dinitrile solvents ; Segment mobility

Source: Springer Online Journal Archives 1860-2000

Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics

Notes: 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.

Type of Medium: Electronic Resource

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

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A novel method of preparing of glass capillary columns: Low-temperature plasma etching and polymerization (1979)

Masada, Y. ; Hashimoto, K. ; Inoue, T. ; [et al.]

Weinheim : Wiley-Blackwell

Journal of High Resolution Chromatography 2 (1979), S. 400-404

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ISSN: 0935-6304

Keywords: Gas chromatography ; Capillary, glass ; Low temperature plasma etching ; Polymer film on the inner surface from organosilicone monomer ; Flexibility of this new method discussed ; Discharge chamber described ; Chemistry ; Analytical Chemistry and Spectroscopy

Source: Wiley InterScience Backfile Collection 1832-2000

Topics: Chemistry and Pharmacology

Notes: A novel method is described for the preparation of stable glass capillary columns (glass open tubular columns), including the etching and formation of a polymer film on the inner glass capillary surfaces. The approach used here is based on low-temperature plasma etching and polymerization. Under the influence of a field of radio frequency discharge, low pressure gases of fluoric compounds, introduced into the glass capillary tube, generate excited fluorine radicals which etch the inner surface. The plasma of organosilicone monomer in the glass capillary yields a uniform polymerized film on the inner surface. The resultant material functions as a good stationary phase for glass capillary gas chromatography (GC2). The inner surfaces treated with such a plasma, can be studied by means of a scanning electron microscope (SEM). The flexibility of this method permits the use of various stationary phases and surface modification.

Additional Material: 8 Ill.