Biodegradable foam created from milk and clay
By Ben Coxworth
October 21, 2010
It’s always a bummer when you take something like a computer or TV out of its box, and realize that all that Styrofoam is just going to end up in the landfill. Although it can be recycled, due to transport costs and lack of market demand, most cities don’t do so. There’s also the fact that it’s made from petroleum – so it's a long way from being sustainable. Fortunately, though, an international team of scientists has recently developed a biodegradable foam. It’s made from clay and casein, which is a naturally-occurring protein in cow’s milk.
Casein is already used in some adhesives and paper coatings, but it lacks strength and is water-soluble. The small amount of clay in the foam gives the casein the needed water resistance, while the addition of a biocompatible agent called glyceraldehyde boosts its strength by cross-linking its molecules together.
The mixture is then freeze-dried, creating an aerogel that is then cured in an oven for added strength. The finished product has been deemed strong enough for use commercial applications, such as furniture cushions, insulation, packaging, and other products.
When the team added some of the foam to a compost media, almost of a third of the material broke down within 30 days.
The research was recently published in the journal Biomacromolecules.