Innovative core elements
The innovative idea behind the project is the development of a novel thermo-formable fibre-based tray meeting the requirements for fresh food packaging in terms of antimicrobial and barrier properties. For this, the physical properties of fibre-based materials will be modified to introduce thermoplasticity, which is essential for the production of trays. Such modifications are expected to push paper and fibre-based materials into a novel class of products exhibiting extraordinary properties where nearly no eco-friendly solutions are yet present on the market.
To develop fibre-material with thermoplastic properties, the functional groups of cellulose fibres have to be chemically modified. For this purpose, the hydrophilic cellulose will be partially converted to a hydrophobic material to introduce ductile properties. The degree of substitution is a central question of research in terms of the balance of hydrophilic and hydrophobic properties of the fibres to meet requirements of paper making process (hydrophilic functionality) as well as the thermo-forming process (hydrophobic functionality).
Ductile barrier coating
The experimental strategy for the development of ductile barrier coating with simultaneous oxygen and water vapour barrier will be a multi-layer approach. For the moisture barrier, hydrophobic polymers like waxes will be evaluated. The functionality of the second layer will be the barrier function against oxygen. Here, hydrophilic polymers like starches and/or polyvinyl alcohol (PVOH) will equip the tray material. The barrier properties of the individual layers will be tuned via introduction of cross-linker like tri- or di-carboxylic acids like citric acid. Furthermore, tensile properties of the multilayer film will be modified, using inorganic fillers. Both, the tuning of ductility and barrier functionality will be evaluated by establishing an experimental matrix.
Formulation of new bio-based antimicrobial coatings
Antimicrobial coatings will be obtained by two different research methods: the use of bio-based antimicrobial agents and by the development of superhydrophobic coatings. Firstly, the incorporation of antimicrobial agents into the eco-packaging will be simultaneously evaluated following two approaches:
- Incorporation of antimicrobial compounds using spray coatings methods.
- Incorporation of antimicrobial compounds in the matrix via melt-processes.
In parallel of these two approaches, antimicrobial activity will be obtained by the development of super-hydrophobic coatings.
In addition to antimicrobial properties, water-resistance and durability (contact angle, impurity tests, easy-to-clean tests after abrasion) will be evaluated on the developed super-hydrophobic coatings, in the framework of applying the coating on packaging material.