A team of researchers from the University of the Basque Country in Spain and Colorado State University have created packaging material that is fully recyclable.

To develop the new material, the team examined two different chemically recyclable homopolymers — poly(gamma-butyrolactone) and poly(trans-hexahydrophthalide) — and combined them to make copolymers, taking properties from each. For instance, poly(gamma-butyrolactone) demonstrates the appropriate rigidity, or mechanical properties, required of packaging while also demonstrating high permeability, meaning that its barrier likely would not hold up against assorted gases and vapors that could potentially impact food safety or quality. Meanwhile poly(trans-hexahydrophthalide) is highly rigid with low permeability.

To achieve the desired mix of low permeability and appropriate rigidity, the team altered the composition of both homopolymers and combined them to achieve the desired blend of characteristics. The result, according to the team, is packaging that challenges the performance of other biodegradable polymers currently in development.

What sets plastic apart as an ideal material, particularly for food packing are its light weight, high ductility and low permeability to vapors and gases. Combined, these characteristics serve to enhance packaged food safety and quality. However, plastic is generally non-recyclable and nonbiodegradable, which is why the world is now overwhelmed by the material as it occupies landfills and even the world’s oceans.

Although biodegradable alternatives to plastic currently exist, often it is at the expense of one of the desired properties offered by plastic. One such example often touted as an alternative to plastic is poly(lactic acid). Poly(lactic acid) is a biodegradable polymer that is a promising substitute for plastic. However, what sets it back is its high rigidity and high permeability.

The team has detailed their findings in the journal Nature Communications.

To contact the author of this article, email mdonlon@globalspec.com