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Cornstarch Foam

Compostable and water-soluble cushioning and thermal insulation.


Cornstarch foam caught the eye of the U.S. Navy as they looked for an alternative to styrofoam (expanded polystyrene or EPS) that they could safely dispose in the ocean. After extensive testing they found cornstarch foam was the perfect solution, because they could just mix the foam in a big pulper, let it break apart, and release it into the ocean with no detrimental effects to the marine environment.

Cornstarch foam is a renewable alternative to styrofoam. It performs comparably to EPS both in drop tests and as thermal insulation. Unlike most foams, cornstarch foam is compostable, and it doesn’t need the high heat of an industrial composter to break down, so even if the material somehow made its way to the ocean, it would still decompose.


The easy degradation of cornstarch foam is both a blessing and a curse. The material does not hold up well in water, so in cases where packaging might come in contact with moisture, the foam needs a plastic liner. This plastic liner can be difficult to recycle and adds an unwanted level of complexity to the end-of-life disposal process.