Image courtesy www.aqua-velvet.com

Foam does more than cushion the inelegant landings of would-be circus performers; we use it to pad furniture, for insulation, packaging, and miscellaneous other products, such as foam-coated wire hair curlers that resemble play-doh spaghetti.  While we love foam because it’s light-weight, absorptive, insulating, and so on, the manufacturing process is energy-intensive and an awful lot of it winds up accumulating in landfill. 

In response to the problem, scientists have developed an “ultra-light biodegradable foam plastic material made from two unlikely ingredients: The protein in milk and ordinary clay” (Physorg.com).  Before you go out and throw some pottery shards in your 2%, let me explain how this works.  Nearly all of the protein in cow milk is casein, and we already use it in an industrial setting to make adhesives and paper coatings.  The substance is not particularly strong and it’s water-soluble, so to “beef up” the casein and increase its water resistance the researchers “blended in a small amount of clay and a reactive molecule called glyceraldehyde, which links casein’s protein molecules together” (Physorg.com).

Powdered casein courtesy www.spectrafix.com

The resulting mixture was promptly freeze-dried, producing a “spongy aerogel, one of a family of substances so light and airy that they have been termed ‘solid smoke.’  To make the gossamer foam stronger, they cured it in an oven, then tested its sturdiness. They concluded that it is strong enough for commercial uses, and biodegradable, with almost a third of the material breaking down within 30 days” (Physorg.com).  You can read more about aerogel here.

Images courtesy Biomacromolecules

The biodegradable foam could find a use as a packing material or as a protective coating that degrades after a period of time to reveal a different material underneath.  I suppose you could also shoot it out of a circus cannon but I’m not sure the Ringling Brothers would be keen about it.

WU XING:

I’ve filed biodegradable foam under earth because it’s made with clay!

Cited:

“Development of Biodegradable Foamlike Materials Based on Casein and Sodium Montmorillonite Clay.” Tassawuth Pojanavaraphan, Rathanawan Magaraphan, Bor-Sen Chiou, David A. Schiraldi. Biomacromolecules 2010 11 (10), 2640-2646.

“Biodegradable Foam Plastic Substitute Made from Milk Protein and Clay.” Physorg.com 10/20/10. Accessed 11/16/10. URL