Edinburgh Napier University

  Poly (butylene adipate-co-terephthalate) (PBAT) is a biodegradable polymer recognized for its potential to reduce plastic waste due to its biodegradability and compostability. However, conventional end-of-life options for PBAT, such as composting and biodegradation, involve additional costs, require substantial space, and consume significant energy, which may not align with broader sustainability goals. Therefore, an alternative approach through recycling is highly desirable. This study investigates the recyclability of neat PBAT and Joncryl ADR 4468-modified PBAT with 0.5 wt% Joncryl, a multifunctional epoxy-based chain extender known to enhance the processing stability and properties of polymers. The research evaluates the tensile, flexural, thermal, and rheological properties of the materials after multiple injection molding cycles to provide comprehensive data on their performance under re-processing conditions. The results demonstrate that neat PBAT retains its tensile modulus with only a~ 6% reduction after seven cycles, while Joncryl-modified PBAT exhibits a 26% increase in modulus after five cycles, attributed to enhanced branching. Additionally, modified PBAT showed superior rheological stability and resistance to thermal degradation compared to unmodified PBAT. This study highlights the potential of mechanical recycling to extend the lifecycle of biodegradable polymers, reducing environmental impact and conserving resources.

Highlights
• 0.5% Joncryl enhances PBAT recyclability by preserving mechanical properties.
• Both PBAT and Joncryl-PBAT retain tensile strength, supporting recycling.
• Joncryl-PBAT resists degradation, showing stable modulus after reprocessing.
• Reprocessing raises crystallization temperature.
• Joncryl-PBAT maintains higher viscosity and modulus, resisting degradation.