Compatibilization strategies and mechanical performances of starch-based blends for sustainable packaging

Starch-based biodegradable polymer blends are promising candidates for sustainable packaging, pairing renewability and biodegradability with reducing environmental burdens. However, thermoplastic starch is hindered by inherent hydrophilicity, limited mechanical strength, and high moisture sensitivity. Moreover, the intrinsic incompatibility between starch and biodegradable polymers such as poly(lactic acid) and poly(butylene adipate-co-terephthalate) leads to poor interfacial adhesion, phase separation, and reduced mechanical integrity. Addressing this interfacial disparity is therefore essential to achieving performance levels suitable for large-scale packaging applications. This review systematically evaluates recent advances in compatibilization strategies for starch-based biodegradable polymer blends, which are categorized into three major classes, namely, physical, reactive, and hybrid nanofiller-assisted approaches. Each strategy is analyzed in terms of its interfacial mechanisms and their effects on morphological evolution and overall mechanical performance. Emerging green compatibilization pathways, including deep eutectic solvent (DES)-assisted and bio-derived systems, are also assessed for their potential to reconcile environmental sustainability with industrial scalability. Reactive and hybrid methods generally provide superior interfacial stability and mechanical reinforcement, though challenges persist regarding processing control, scalability, and biodegradability preservation. Collectively, these insights establish a framework for designing high-performance starch-based blends that integrate structural functionality with sustainable processing, accelerating their transition from laboratory-scale concepts to practical, low-carbon packaging solutions.