NEW RESEARCH RESULTS: Biobased nanocomposite coating for food packaging materials

Thursday, 25 March 2010 18:20

Jari Vartiainen, Mikko Tuominen and Kalle Nättinen developed a new biobased nanocomposite coating with improved barrier properties. Nanotechnology in food packaging is expected to grow strongly over the next five years as the increased globalization sets demands for shelf life enhancing packaging. Applications of nanotechnology include e.g. improved barrier, mechanical and antimicrobial properties.

Nanocomposite coatings with improved properties were produced from ultrasonic dispersed chitosan and hydrophilic bentonite nanoclay. Biohybrid coatings were applied onto argon–plasma-activated LDPE coated paper. The intercalation of chitosan in the silicate layers was confirmed by the decrease of diffraction angles as the chitosan/nanoclay ratio increased. Nanocomposite multilayer coatings had improved barrier properties against oxygen, water vapor, grease, and UV-light transmission.

Oxygen transmission was significantly reduced under all humidity conditions. In dry conditions, over 99 % reduction and at 80 % relative humidity almost 75 % reduction in oxygen transmission rates was obtained. Hydrophilic chitosan was lacking the capability of preventing water vapor transmission, thus total barrier effect of nanoclay containing films was not more than
15 % as compared with pure chitosan. Because to very thin coatings (≤1 μm), nanoclay containing chitosan did not have antimicrobial activity against test strains.

All coating raw materials were ‘generally recognized as safe’ (GRAS) and the calculated total migration was in all cases <6 mg/dm2, thus the coatings met the requirements set by the food packaging legislation. Processing of the developed bio-hybrid nanocomposite coated materials was safe as the amounts of released particles under rubbing conditions were comparable with the particle concentrations in a normal office environment. The developed biobased nanocomposite coatings can be potentially exploited as safe and environmentally sound alternatives for synthetic barrier packaging materials.

Reference:

Vartiainen, J., Tuominen, M., Nättinen, K. Bio-hybrid nanocomposite coatings from sonicated chitosan and nanoclay. Journal of Applied Polymer Science 116 (2010), 3638 – 3647.

More information:

Jari Vartiainen, This e-mail address is being protected from spambots. You need JavaScript enabled to view it
Research Scientist
Tel. +358 20 722 6188

Kalle Nättinen, This e-mail address is being protected from spambots. You need JavaScript enabled to view it
Research Scientist, Team Leader
Tel. +358 20 722 3512