Slime and Poly(Viny1 Alcohol) Fibers An Improved Method Gary G. Stroebel, Jonathan A. Whitesell, and Robert M. Kriegel Augusta College, Augusta, GA 30910
During a n impromptu, day-long "Slime Workshop", our students developed what we think are significant improvements to procedures reported previously ( 1 , 2 ) .The principle modification involves use of a n 8% (wlv) stock solution of poly(viny1alcohol) (PVA)in water, rather than the 4% aqueous solution utilized in other procedures. We found that combining portions of our PVA solution with equal volumes (1:l)of 4% aqueous sodium borate produces a less sticky and more viscous (and, therefore, less messy!) version of Slime. Furthermore, by slowly adding the 4% sodium borate to a vigorously-stirred (sturdy glass rod, by hand) 8% PVA solution in a volume ratio of 1:2, a gellike material is formed immediately that can be handled convenientlv. without the "kneadinn" necessarv for thickening ~ h m produced e from more &lute PVA ;ohtions. This feature i s vanicularlv useful for demonstrtlrion purposes, because assistants and even spectators can examine and test samples (by bouncing them, stretching them, etc.) soon after formation, because the material formed in this manner does not flow readily, or adhere to hands and clothing. Our students also developed an interesting new demonstration of the unique properties of the material formed
from equal volumes of reactants. When 10&200 mL (we used Slime recovered from several experiments) are placed into a tightly-stoppered 500-mL Erlenmeyer flask, slow inversion of the flask permits the Slime to wet the inner walls and flow like a classical liquid. However, rapid and vigorous shaking of the inverted flask results in coalescence to a material sufficiently rigid to bounce within the flask. Slow movement of the flask once again permits the sample to flow as a liquid. Finally, treatment of the 8% PVA solution with acetone provides PVA fibers as described for use with the more dilute solutions ( 1 , 3 ) . In preparing the 8% PVA solution, we recommend overnight agitation with a magnetic stirrer in order to achieve homogeneity and complete dissolution of the WA lumps that inevitably form, even upon slow introduction of the solute, with stirring, to water. Literature Cited
C. E.Jr J Chem.Edue.1992.69.915. 2. Cassasss, E.2.: Saquis, A. M.; Van Dyke, C.H.J. Chom.Edue. 1988,63,57. 3. Sherman, Marie C.J. Chom.Edue 1992.69.883. 1.Rod"guer,F;Carraher,
Volume 70 Number 11 November 1993
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