Gas barrier properties are the Achilles heel when it comes to using biopolymers in (fresh) food packaging. Around the world, scientists and industry are working - often together - to develop feasible alternatives based on renewable resources to replace the use of conventional petroleum-based plastics. Solutions up to now have mainly involved the use of 'hybrid' laminates; at the same time technologies such as atomic layer deposition, in which Al2O3 coatings with thicknesses of 10-50 nm are "grown" on bioplastic materials, are being explored to discover whether these produce suitable barriers for use in food packaging, without affecting the biodegradability.
By comparison, the use of wood to improve permeability against, for example, oxygen, sounds relatively low-tech; old school, even.
Yet this is exactly what they're doing in Norway. A team of Norwegian scientists at the Foundation for Scientific and Industrial Research (SINTEF), in collaboration with the Norwegian biorefinery Borregaard, a company specialized in the production of advanced wood-based biochemical alternatives to traditional petroleum-based chemicals, is working on the development of a membrane made of what is called microfibrillated cellulose (MFC). MFC consists of plant fibers that are only 100 nanometers in diameter, but that can be extremely long, making them highly suitable as a reinforcement material for biodegradable plastics. More significantly, MFC has the ability to disable access to gases such as oxygen, offering potential for use in biodegradable food packaging, whether in bottles, jars or plastic foil. In addition, sensors integrated into the packaging can provide information about the condition of the food: the temperatures to which it has been exposed or whether it is ready to spoil. Developing safe and sustainable packaging that prolongs the shelf life of food, helping to persuade more consumers to choose healthier alternatives and at the same time, reducing food waste, is a major challenge confronting packaging manufacturers today.
The project, called NanoBarrier, is to begin in March 2012 and run for four years. Åge Larsen, a senior researcher at the SINTEF Group and the project manager, said, "The use of bioplastics may help to promote sustainable development. The overall objective is to create materials and packaging that are climate neutral." And he adds: 'In any case, as the oil runs down, we are going to need alternative raw materials.'
Asked why, with so much plastic waste available, the team was not looking more closely at the opportunities posed by recycling, Larsen pointed out that, to all purposes and intents, recycling still equals downcycling. "Recycling is useful, but in practice, recycled plastics often end up a step or two lower down the quality ladder than the original raw material," he says. "This is why we believe that MFC fibrils in combination with bioplastics will help us produce high-quality, environmentally friendly packaging."
The project is receiving funding from the European Union. Despite not being a member of the EU, Norway is a prominent presence among the - in total - 15 participants.
The first prototypes are expected in a couple of years.