DEVELOPMENT OF BIOBASED POLYESTERS FOR BARRIER COATINGS IN MONO-MATERIAL PLASTIC PACKAGING APPLICATIONS

In recent years, sustainability has become a central priority across industries, driven by the urgent need to mitigate climate change and reduce environmental impact. The chemical sector, particularly polymer manufacturing, is embracing this shift by developing eco-friendly alternatives to fossil-based materials. Traditional petroleum-derived packaging materials pose several challenges, including waste management issues, resource depletion, limited recyclability, environmental persistence, and price volatility. As a result, the growing demand for sustainable packaging is accelerating research into alternative materials. Polyester resins are widely used in flexible packaging due to their excellent mechanical properties and processability. The incorporation of biobased monomers is increasingly seen as a viable solution for producing sustainable polyesters. In this context, furan-based building blocks, obtainable from renewable feedstocks such as lignocellulosic biomass and agricultural residues, can be synthesized through chemical, biological, or biotechnological routes, contributing to reduced greenhouse gas emissions and decreased dependence on finite fossil resources. Moreover, furanic polyesters provide coating films with excellent barrier properties against gases, moisture, and oils, making them promising candidates for high-barrier solutions in mono-material plastic and paper packaging. These bio-based alternatives could effectively replace traditional fossil-derived aromatic monomers such as terephthalates and isophthalates. This study investigates the potential of furan-based monomers in solventborne polyester systems to develop fully organic, high-barrier coatings for mono-material plastic and paper packaging. The aim is to create sustainable, high-performance materials that comply with food safety standards and promote circular economy principles. To this end, novel polyester formulations incorporating different ratios of furanic monomers (2,5-furandicarboxylic acid and its methyl ester) and renewable glycols (1,5-pentanediol, diethylene glycol) were synthesized and characterized. The resulting materials were applied as coating layers on plastic and paper substrates and evaluated in terms of their barrier properties.