Boron is essential for cross-linking the polymer chains in Silly Putty. In real Silly Putty, the polymer chains are made from polyvinyl alcohol, but you can make your own slimy polymeric putty with Elmer's glue. Here's a good recipe from Steve Spangler's website:
This recipe is based on using a brand new 8 ounce bottle of Elmer’s Glue. Empty the entire bottle of glue into a mixing bowl. Fill the empty bottle with warm water and shake (okay, put the lid on first and then shake). Pour the glue-water mixture into the mixing bowl and use the spoon to mix well. Add the glue-water mixture to the glue in the mixing bowl. Go ahead… add a drop or two of food coloring.
Measure 1/2 cup of warm water into the plastic cup and add a teaspoon of Borax powder to the water. Stir the solution – don’t worry if all of the powder dissolves. This Borax solution is the secret linking agent that causes the Elmer’s Glue molecules to turn into slime.
While stirring the glue in the mixing bowl, slowly add a little of the Borax solution. Immediately you’ll feel the long strands of molecules starting to connect. It’s time to abandon the spoon and use your hands to do the serious mixing. Keep adding the Borax solution to the glue mixture (don’t stop mixing) until you get a perfect batch of Elmer’s slime. You might like your slime more stringy while others like firm slime. Hey, you’re the head slime mixologist – do it your way!
When you’re finished playing with your Elmer’s slime, seal it up in a zipper-lock bag for safe keeping.
The borax dissociates to borate ions in solution. The -OH groups on the borate ions form weak hydrogen bonds with the -OH groups of the polyvinyl alcohol (or glue polymer), which allow the polymeric chains to link and unlink as the putty (slime) stretches.
See the Boron (B) atom in the middle? Neat, huh? |
And that's probably more than you'll ever need to know about boron. Oh, except that boron compounds make a pretty green flame when burned: