Longer Shelf Life and Fewer Plastic Substances in Food29 January 2015
Synthetic materials are convenient in many respects, but they have one disadvantage: they are permeable to gases.
In order to make plastic more impervious, Ruhr-Universität engineers are applying wafer-thin layers onto the surfaces, which not only increase the shelf life of food in plastic packaging, but also prevent the migration of substances from the plastic into the food.
Light and break-proof synthetic materials are everywhere.
However, people are still concerned that harmful substances may seep into the food.
Currently, supplying baby food in plastic containers is being debated.
“A synthetic material that does not leak any substances does not exist,” said Prof Peter Awakowicz, Head of the Institute for Electrical Engineering and Plasma Technology at Ruhr-Universität.
“Using our coating, the volume of those substances could be reduced to a mere one per cent of the current volume.”
Coating Plant for PET Bottles Already Available
Together with his team, Dr Awakowicz researched how an object can be coated with a specific synthetic material using plasmas.
The results are affected by many parameters, such as plasma density, oxygen content, and the intensity of ion bombardment. In collaboration with partners from the industry, the RUB engineers have optimised the process to a considerable extent for PET bottles.
The research consortium also owns a coating plant.
A Barrier Layer from Glass
The applied barrier layer that makes plastic more impervious is made from wafer-thin glass.
The RUB researchers did not apply it directly to the plastic, however, because they discovered that the oxygenic plasma process necessary for this purpose destroys the synthetic surface.
Therefore, Dr Awakowicz’ team initially coated the surface with an oxygen-free protective layer, followed by the glass layer.
The engineers also demonstrated that the protective layer transforms the glass layer following application, thus making the plastic even more impervious.
The coating process is relevant not only for food packaging. Artificial kidneys and organic light-emitting diodes are also made from synthetic materials and could benefit from the process.
A detailed article with pictures can be found in the online magazine RUBIN, the RUB’s science magazine:http://rubin.rub.de/en/making-synthetic-materials-more-impervious.