Metallic coatings in food packaging are often difficult to recycle, but UK researches have developed a new transparent film that could replace some metallic layers.
Reported in peer- reviewed journal Nature Communications, the new films can be produced using a cheap, environmentally friendly process and provide a similar level of food protection to the metallic layers, while also being full recyclable.
Multi-material composites which include metallic layers offer an essential barrier for food preservation, and is an industry standard approach to achieving necessary gas barrier performance. But these layers are difficult to separate and recycle.
University of Oxford Professor Dermot O’Hare and colleagues have created synthesised thin films made from nanosheets of layered double hydroxides – a fully inorganic material – which are developed in a process that only needs water and amino acids.
They are similarly impermeable to oxygen and water vapour as regular metallic coatings, while being transparent and mechanically robust. The films are also synthentic, meaning its composition is fully controllable.
Researchers are still ensuring the development of the films can be as cost effective as aluminium vapourisations. The new films have met several safety standards for contact with food but further testing is being undertaken before they can be used in packaging.