BioORMOCER®—compostable functional barrier coatings for food packaging

Abstract

Biodegradable packaging materials are already in use. However, there are severe re-strictions preventing the broad application in food packaging, especially due to insufficient barrier properties. Our idea was to improve these properties with a biodegradable coating. The Fraunhofer-Institut für Silicatforschung ISC has been developing high-barrier coatings for various packaging applications based on a class of materials with glass-like structural units, named ORMOCER®. How-ever, these state-of-the-art ORMOCER® coatings are not biodegradable. The aim of our work was to modify ORMOCER® to become biodegradable and, at the same time, preserve the barrier and functional properties. This was achieved by the incorporation of functionalized tamarind hemicellu-lose Glyate® into the ORMOCER® matrix. For this purpose a two-step amination reaction of Glyate® was chosen. The aminated product was analyzed by FTIR, solid-state NMR and elemental analysis. New aminated Glyate® containing bioORMOCER® lacquers could be synthesized. Lacquer quality assessment was performed by Raman spectroscopy. The properties of the resulting coatings were evaluated by laser scanning microscopy (LSM), oxygen transmission rates (OTR) measurements, E-Module determination and adhesion tests. Standardized tests for compostability, overall migration and antimicrobial properties were performed for the bioORMOCER® coatings. The evaluation showed that the new bioORMOCER® coatings are suitable for sustainable food packaging.