Cross Linked Polymers!

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In this segment we finish preparing our “Silly Putty” from Glue and Borax.

Items

  • Kitchen Scale
  • Borax
  • Elmer's Glue
  • Water

In this part we finish preparing our silly putty by rinsing it in water to wash away any unreacted sodium tetraborate. Without rinsing, you may find your sample is tacky and leaves the skin of your hands dry by sapponifying the fats and oils in your skin (aka “dishpan hands). Yet the rinsed sample, with some stretching and kneading, can be formed into a clean, pliable sample of a white amorphous solid that kids will enjoy handling because of its “nonNewtonian” properties (it behaves like a liquid under some conditions, as a solid under others).

Students normally ask to keep the reacted samples. If you do send them home, send them sealed in a plastic bag and keep them in your lab until the end of the day to avoid student temptation to handle the material in other classes. Caution the students to avoid letting the reacted polymer come into contact with carpet, upholstered surfaces or fabrics (it can stick to fibers). If a sample becomes dry and brittle, it can be rehydrated with a few drops of distilled water. You may choose to tint the solution or the dissolved glue with vegetable dye, yet we normally do not to avoid staining our hands when handling it.

Bonus! Stirring your solution with a highlighter will allow your final sample to fluoresce under a black light.

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