Sweden – research indicates potential for ecofriendly plastics to protect food

Xylan is one of the most common carbohydrates in nature present in both hardwood and annual plants such as barley, rye, wheat and maize. Chalmers University of Technology reports that soon xylan will be able to replace aluminium and polymers in packing.



Despite the fact that xylan exists in these large amounts in nature and in by-product from industrial processes, it is not used today in applications as plastic materials. One reason for this is the lack of knowledge of the material properties of xylan. The chemical structure of xylan depends on the plant source.



Maria Gröndahl has studied the properties of xylan-based materials: “If we were able to understand the effect of the molecular structure of xylan on material properties, we could create tailor-made xylan-based materials with desired properties.”



In this study, xylan was extracted from aspen wood, corn fibre and barley husks and relationships between chemical structure and material properties were evaluated. The effect of side groups on solubility, interactions with water, film formation and crystallinity as well as thermal and mechanical properties were studied. The film forming ability and the flexibility of the material were controlled by addition of plasticizers.



It was shown that xylan-based films are excellent oxygen barriers. This is an important property in packaging of oxygen sensitive products such as pharmaceuticals and food products such as juice, coffee and snacks.



The great majority of plastic materials in use today are based on fossilic raw materials. These materials contribute to enhanced greenhouse effects when burned. Xylan-based materials, however, are carbon dioxide neutral and a more environmentally friendly alternative. The material can be composted after use since it is biodegradable. This study shows that xylan has a potential as a renewable, biodegradable packaging material.



The thesis “Effects of Molecular Architecture of Xylans on Material Properties” was defended in public on October 27, Chalmers tekniska högskola i Göteborg