Reactive Compatibilization of Zizania latifolia Leaf Powder‐Reinforced Biodegradable Polyester Composites With a Grafted Compatibilizer and an Epoxy Chain Extender

ABSTRACT Agricultural‐residue fillers can lower the material footprint of biodegradable composites, but their hydrophilic surfaces often weaken polyester interfaces. This study resolved the individual and combined effects of maleic‐anhydride‐grafted poly(lactic acid) (MAH‐g‐PLA) and a multifunctional epoxy chain extender (ADR) in a 70/30 poly(lactic acid)/poly(butylene adipate‐co‐terephthalate) blend containing Zizania latifolia leaf powder (ZLP). Low‐filler prescreening, single‐factor gradients, and factorial controls were assessed by tensile testing, melt mass‐flow rate (MFR), dynamic rheology, Fourier‐transform infrared spectroscopy, scanning electron microscopy, differential scanning calorimetry, and thermogravimetry. The balanced formulation contained 5 wt% ZLP, 5 wt% MAH‐g‐PLA, and 0.5 wt% ADR. MAH‐g‐PLA increased tensile strength from 17.75 ± 0.81 to 26.54 ± 1.94 MPa and raised the onset degradation temperature from 294.64°C to 306.72°C. Subsequent ADR addition increased elongation at break from 9.97% ± 0.71% to 43.76% ± 5.44%, reduced MFR from 18.97 ± 0.60 to 15.13 ± 0.35 g/10 min, and increased G ′ from 65 to 160 Pa at 0.1 rad s −1 . The combined evidence indicates complementary interfacial‐load‐transfer and melt‐viscoelastic effects, establishing a factor‐resolved composition–structure–property framework for reactively compatibilized ZLP/PLA/PBAT biocomposites.