Bio-based terpolymer moisture barrier materials for sustainable food packaging

Overview

This research proposes a new class of multi-functional moisture barrier materials based on terpolymers that combine bio-based hydrophobic comonomers with adhesion-promoting functional monomers and cyclic ketene acetals (CKAs). The resulting polymers are designed to serve as skin layers in co-extruded or blended food packaging films, offering both moisture resistance and controlled degradability. By integrating hydrophobic bio-derived monomers such as myrcene, farnesene, or alkyl methacrylates with functional monomers like glycidyl methacrylate and hydrolyzable CKAs, these terpolymers address the dual challenges of barrier performance and end-of-life sustainability in packaging applications.

Technical specifications

Key material design features:

• Hydrophobic backbone: Bio-based dienes (myrcene, farnesene) and vegetable oil-derived alkyl methacrylates provide inherent moisture resistance
• Amphiphilic character: Copolymerization with polar functional monomers enables tunable surface and adhesion properties
• Degradable junctions: CKAs introduce ester linkages along the polymer main chain via radical copolymerization, enabling hydrolytic chain scission
• Adhesion capability: Low fractions of glycidyl methacrylate (GMA) provide compatibilization with PLA and other substrate layers
• Processing versatility: Designed for co-extrusion, blending, and compatibilization as skin layers in multilayer film structures

Research approach:

• Synthesis and characterization of hydrophobic monomer-rich compositions for baseline moisture barrier testing
• Incorporation of GMA at low loadings to confirm adhesion without compromising barrier performance
• Terpolymerization with CKAs to introduce hydrolyzable chain scission nodes
• Blending studies with PLA to evaluate compatibility and adhesion in small-scale mixers
• Degradation testing using available analytical equipment

Technology readiness level

This research is at an early stage (TRL 1-2). The hypothesis has not yet been experimentally validated. The research team has prior experience with bio-based dienes and vegetable oil-based methacrylates for thermoplastic elastomers and has demonstrated copolymerization of dienes with polar monomers. However, the specific combination of these monomers with CKAs for moisture barrier applications requires systematic validation. Key next steps include confirming moisture barrier properties, optimizing monomer ratios, demonstrating terpolymerization with CKAs, and conducting blending and adhesion studies with PLA. Access to moisture testing equipment is identified as a critical need for advancing this research.