One-Pot Synthesis of PBAT from PET Waste Using Metal-DES Catalytic Systems for Sustainable Packaging Applications

The accumulation of polyethylene terephthalate (PET) waste poses a major environmental concern, highlighting the need for effective recycling methods. Converting PET waste into high-value polymer materials offers a viable strategy to address plastic pollution. This research investigates the one-pot synthesis of poly-(butylene adipate-co-terephthalate) (PBAT) using various metal catalysts in combination with deep eutectic solvents (DESs) as cocatalysts. Different metal-based catalystszinc, tin, titanium, and antimonywere tested with DES systems such as choline chloride-glycerol (ChCl-Gly), choline chloride-para-toluene sulfonic acid (ChCl-PTSA), and choline chloride-urea (ChCl-Urea). The antimony trioxide/ChCl-Gly system demonstrated superior catalytic activity, yielding PBAT with molecular weights of 70,000-75 000 g/mol, followed by Ti > Sn > Zn. Optimized reaction conditions (0.25 wt % catalyst and 0.25 wt % ChCl-Gly at 220 °C) improved polymer characteristics over conventional methods. The resulting PBAT was analyzed for its physio-chemical, thermal, and mechanical properties, and PBAT composites were developed for packaging applications. Key thermal and mechanical parameters, including melt flow index (MFI), tensile strength, and elongation at break, were measured. Thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC) confirmed the polymer's thermal stability, demonstrating its potential for commercial packaging. This innovative method presents an alternative chemical recycling route for PET waste utilization, contributing to sustainable packaging material development.