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Home  >  Journal list  >  Polymer Journal  >  Vol.17  No.4 (1985)  >  pp.607-619

Polymer Journal
<<Previous article Vol.17  No.4 (1985)   pp.607 - 619 Next article>>

Light Scattering and Viscometric Study on Polyacrylonitrile in Dimethylformamide, Ethylene Carbonate/Water Mixture, and Aqueous Nitric Acid

Kenji Kamide1), Yukio Miyazaki1) and Hidehiko Kobayashi2)
1) Textile Research Laboratory, Asahi Chemical Industry Company, Ltd.
2) Research and Development Administration, Asahi Chemical Industry Company, Ltd.


ABSTRACT:  An attempt was made to determine the Flory theta solvents and the unperturbed chain dimension A of polyacrylonitrile (PAN). A sample of PAN, polymerized using redox catalyst and having isotactic triad of 26% and syndiotactic triad of 24%, was fractionated by successive solution fractionation method to give a series of fractions with the ratio of weight- to number- average molecular weight MwMn of 1.15—1.41. A mixture of ethylene carbonate (EC) and water containing 85 wt% EC and aq. 55 wt% nitric acid was identified by the light scattering method to be Flory theta solvents at 25°C whose second virial coefficients were zero. The Mark–Houwink– Sakurada (MHS) equations were determined in various solvents. In the theta solvents, the radius of gyration ⟨S2z1⁄2 was proportional to Mw1⁄2 and the exponent a in MHS equations was always 0.5. The Flory viscosity parameter Φ was 2.3×1023 in DMF and 2.8×1023 in theta solvents, independent of Mw. The unperturbed chain dimension parameter A, the conformation parameter σ and the characteristic ratio C were determined by thermodynamic and hydrodynamic methods. Both methods gave consistent results. The solvent dependence of these parameters was demonstrated.


Keyword:
Flory Solvent/ Unperturbed Chain Dimension/ Polyacrylonitrile/ Second Virial Coefficient/ Mark–Houwink–Sakurada Equation/ Flory viscosity Parameter/ Conformation Parameter/ Characteristic Ratio

Published online: March 03, 2006
© Copyright, 2006 by The Society of Polymer Science, Japan

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