Viscosities of poly(N-vinylacetamide) solutions in the presence of salts, urea and guanidine hydrochloride |
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Authors: | J S Hong H Maeda M Akashi |
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Institution: | (1) Dept. of Chemistry Faculty of Science Kyushu University Fukuoka 812-81 Japan, JP;(2) Department of Applied Chemistry and Chemical Engineering Faculty of Engineering Kagoshima University Kagoshima 890, Japan, JP |
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Abstract: | Summary In the aqueous solutions of poly(N-vinylacetamide) in the presence of Na2SO4 or (NH4)2SO4, the intrinsic viscosities were small and the Huggins constants were large compared with those in water. Similar but much
less effects were observed for NaF. Opposite effects were found, however, for NaSCN. The poor solvent quality of aqueous sulfate
solutions was significantly improved by the addition of guanidine hydrochloride to 3 M or higher. Urea was much less effective
in improving the solvent quality. The different M28.8neffects observed between urea and GdnHCl may be explained by their different
binding affinities to amide group. Solubilization of PNVA flocculates induced by the presence of 0.8 M Na2SO4 took place by adding urea to 1 M, although only small changes were detected in the viscosity behavior accompanying the addition
of 1 M urea.
Received: 12 June 1997 Accepted: 4 August 1997 |
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Keywords: | Poly(N-vinylacetamide) viscosity salting-out urea guanidine hydrochloride |
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