Effective compatibilization of poly(L-lactic acid)/poly(butylene adipate-co-terephthalate) blends via low-dose gamma irradiation

This study addresses the critical challenge of compatibilizing immiscible poly(lactic acid) (PLA) and poly(butylene adipate-co-terephthalate) (PBAT) blends. The aim is to investigate low-dose gamma irradiation (3-5 kGy) as an efficient and clean method to enhance the interfacial adhesion and overall performance of these biodegradable polymer blends, overcoming the limitations of conventional compatibilization techniques. PLA pellets were subjected to gamma irradiation at 3 and 5 kGy before being melt-blended with PBAT in a 50/50 wt% ratio using a twin-screw extruder. The resulting blends were comprehensively characterized to evaluate their molecular, mechanical, morphological, thermal, and rheological properties. Low-dose gamma irradiation induced controlled chain scission in PLA, reducing its molecular weight. This modification significantly improved the compatibility of PLA/PBAT blends, leading to a more homogeneous morphology with elongated PBAT domains. Consequently, the mechanical properties were enhanced, with the 3 kGy irradiated blend showing a 7.7% increase in yield stress and an 8.6% increase in elongation at break compared to the non-irradiated blend. Furthermore, the thermal stability of the blend irradiated at 3 kGy improved, with the onset degradation temperature increasing by 5.3 °C. Low-dose gamma irradiation is a highly effective and promising strategy for compatibilizing PLA/PBAT blends. The controlled degradation of PLA enhances interfacial adhesion, leading to a synergistic improvement in mechanical and thermal properties without the drawbacks of high-dose irradiation or chemical additives. This method offers a scalable and environmentally friendly pathway to develop high-performance, fully biodegradable materials for sustainable packaging and other advanced applications.