Chemical modifications for more sustainable materials: from the laboratory to the market



Improve properties or reduce layers. These have been the strategic lines of the NEWDEFER project of the ITENE technology centre, which is supported by the IVACE and in which work has also been done with active packaging technologies.


Improving the properties of packaging materials is a key area of work to contribute to environmental sustainability, as it allows the reduction of the amount of material used or the substitution of conventional materials with bio-based ones. In this improvement, using chemical modification technologies in melt, ITENE has worked in the NEWDEFER project, supported by the Valencian Institute of Business Competitiveness (IVACE).


On the one hand, multilayer packaging, commonly used, offers excellent barrier properties thanks precisely to the combination of the properties of the materials of the different layers. However, due to the different chemical nature of the materials used, it is necessary to use adhesives to join the different layers. One such material is ethylene vinyl alcohol (EVOH) copolymer, which is used in high barrier applications in the food and cosmetics industry. However, due to their sensitivity to moisture, EVOH copolymers must be used with additional layers in multi-material packaging, increasing their complexity, cost, and difficulty of recycling.


For this reason, at NEWDEFER we have resorted to chemical modification by reactive extrusion of EVOH in order to decrease sensitivity to humidity and increase affinity with other materials, being able to eliminate the use of adhesives when these materials are used in multi-layer structures. In this way, an improved multilayer film with a simplified structure has been obtained for food packaging applications and hygiene or cosmetic products that require a high barrier.


On the other hand, copolymer-reinforced biopolymer formulations have been developed for rigid biodegradable or compostable injection packaging applications. In this case, work has been carried out with two biopolymers, polybutylene succinate (PBS) and polyhydroxybutyrate-co-valerate (PHBV), for which customised copolymers have been synthesised and introduced into the molten polymer matrix, in order to improve the processability and barrier properties of the biopolymers. This enables their use in applications where the barrier of the biopolymer as a monomaterial was insufficient to adequately protect certain foods, in addition to achieving processing conditions similar to conventional materials.


Finally, this project has also worked with active packaging technologies. Specifically, active materials based on EVOH containing different natural bioactive compounds with antioxidant and/or antimicrobial activity have been developed by extrusion. The results achieved in NEWDEFER were presented last 23rd October in a technology transfer session that is available online.


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