Enhancing the properties of PLA/TPS blends using PLA-g-MA as a compatibilizer: a study on thermal, morphological, mechanical, chemical, and biodegradation characteristics

This study investigates the development and optimization of biodegradable polymer blends consisting of polylactic acid (PLA) and thermoplastic starch (TPS), using PLA-grafted maleic anhydride (PLA-g-MA) as a compatibilizer. Blends were prepared with PLA: TPS ratios ranging from 100:0 to 0:100 and compatibilizer concentrations of 0%, 3%, 5%, 7%, and 9%. Mechanical properties and melt flow index (MFI) were assessed for all blends, while thermal stability (TGA), morphological properties (SEM), and chemical and biodegradation behavior were specifically studied for the 70:30 and 80:20 blends at all compatibilizer concentrations. The 70:30 blend demonstrated superior thermal stability, with a weight loss reduction from 9.4 at 0% compatibilizer to 1.9 at 9% PLA-g-MA at 300 °C. SEM analysis revealed a transition from distinct phase separation at 0% compatibilizer to a homogeneous structure at 7% PLA-g-MA, particularly in the 70:30 blend. Biodegradation studies confirmed faster decomposition for the 70:30 blend, achieving 8.7% weight loss over 15 days at 7% compatibilizer, compared to 7.6% for the 80:20 blend under the same conditions. Mechanical property analysis showed significant improvements in tensile strength, impact resistance, and ductility with increasing compatibilizer concentration, particularly for blends with higher TPS content. These findings highlight the versatility of PLA/TPS blends for applications requiring tailored mechanical and thermal properties, along with enhanced biodegradability.