bioORMOCER(®)—Compostable Functional Barrier Coatings for Food Packaging

Biodegradable packaging materials are already in use. However, there are severe restrictions 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(®). However, 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 hemicellulose 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.