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  Home > JCE Print > Journal of Chemical Education > Issues > 1997  > January  >
In the Laboratory
The Gelation of Poly(Vinyl Alcohol) with Na2B4O7 · 10H2O: Killing Slime
K. W. McLaughlin, N. K. Wyffels, A. B. Jentz, and M. V. Keenan
Department of Chemistry, University of Wisconsin-River Falls, River Falls, WI 54022
Cover
January 1997
Vol. 74 No. 1
p. 97
Abstract
The gelation of poly(vinyl alcohol), PVA, with sodium tetraborate decahydrate (borax) to produce "slime" is a popular chemistry demonstration (1). Since the borate serves to cross-link the PVA, the degree of cross-linking can be varied by changing the borate concentration (2). One way of changing the concentration of borate available to hold the PVA chains together is to "disable" the borate by protonation with a strong acid (3, 4). The titration of slime with sulfuric acid (eq 1) allows students to examine the relationship between cross-linking, viscosity, and the onset of gelation. This modification to a popular chemistry demonstration produces an interesting chemistry laboratory experiment designed to introduce students to the relationship between molecular structure and the bulk properties of macromolecules.
More Information
*  Citation
 McLaughlin, K. W.; Wyffels, N. K.; Jentz, A. B.; and Keenan, M. V. J. Chem. Educ. 1997 74 97.
*  Keywords
*  History
 Created:
Last Updated:		 July 29, 1999
June 23, 2005
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