Scientists create biogradable styrofoam from milk

The research was led by David Schiraldi of Case Western Reserve University who told DairyReporter.com: “This is a product option for companies looking for a green, biofriendly material.​ The process itself is also very friendly, in that the only effluent is water vapour.” ​

The results of the study, recently published in Biomacromolecules, ​shows that a material produced using cows milk is both biodegradable and strong enough for commercial uses with almost a third of the material breaking down within 30 days.

Casein​

80 percent of the protein in cow milk is a substance called casein, which is already used in making adhesives and paper coatings.

“Casein shows good film-forming and coating properties as well as excellent barrier properties to nonpolar substances (oxygen, carbon dioxide, and aromas). This makes it an excellent candidate for numerous applications, such as paper coatings, adhesives, and food packagings,”​ said the researchers.

However, casein on its own has limited mechanical strength and is water sensitive, which can restrict its practical applications.

To make the casein more resilient and boost its resistance to water, the scientists blended in a small amount of clay and a reactive molecule called glyceraldehyde, which links casein’s protein molecules together.

The scientists freeze-dried the resulting mixture, removing the water to produce a spongy aerogel, a lightweight material. To make the gossamer foam stronger, they cured it in an oven and then tested its sturdiness.

The researchers say the development comes amid ongoing concern about plastic waste accumulating in municipal landfills, and reliance on imported oil to make plastics.

“These foam-like materials hold promise for a wide range of applications where the low density and environmental friendliness are of great importance; the ultra-low-density layered architectures result in favorable mechanical and thermal insulation properties,”​ the study concluded.

Scale and production​

The group has only created a few small samples of the product so far however the licensee of the technology AeroClay has produced larger samples and is currently working with end user companies, although Schiraldi said that the amount being produced is currently not in production quantities.

In terms of developing the product further on a university level, Schiralidi said he would like to work with a dairy school to see if the scientists can use a dairy product directly, rather than using purified casein.

Although the scientists have previously published a study in Green Chemistry​ testing the material, Schiralidi said that this particular study shows how to increase the mechanical properties of the aerogel, demonstrating its biodegradability.

The scientists claim that the new substance could be used in a range of products such as packaging, furniture cushions and insulation.

Biomacromolecules​ (2010)

"Development of Biodegradable Foamlike Materials Based on Casein and Sodium Montmorillonite Clay”​

Authors: Tassawuth Pojanavaraphan, Rathanawan Magaraphan, Bor-Sen Chiou and David A. Schiraldi

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