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Hydrogen Bonding in Slime

Procedure

• Pour 100ml of 4% polyvinyl alcohol solution into a 250ml beaker, add a couple of drops of food coloring for your favorite color.

• Pour 16ml 4% sodium tetraborate solution into the polyvinyl alcohol solution while stirring vigorously with the supplied wooden stick.

• Stir the solution as fast as you can for 30 seconds or so - until the solution begins to polymerize.

• You now have a colored polymer.

Reactions

Sodium borate hydrolyzes in water to form a boric acid-borate ion buffer with pH around 9.

B₄O₇² (aq) + H₂O <---> HB₄O₇^2- (aq) + OH^- (aq)

The borate ions react with the hydroxyl groups of the poly(vinyl alcohol) [-CH₂ CHOH-]_n to form cross links possibly with the elimination of water. The cross links probably involve hydrogen bonds that break and reform under flow.

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Last Updated: 1/23/03