Effect of Nanochitosan on Shape Memory Performance of In Situ Compatibilized Poly(Lactic Acid)/Poly(Butylene Adipate‐Co‐Terephthalate) Nanocomposites: Morphological, Mechanical, Thermal, and Rheological Investigations

ABSTRACT This study investigates the synergistic effects of nanochitosan (NCh) and a multifunctional epoxy chain extender (ADR) on the morphology, crystallization, viscoelastic behavior, and shape‐memory performance of poly(lactic acid)/poly(butylene adipate‐co‐terephthalate) (PLA/PBAT) blends. Morphological analyses showed that NCh particles were mainly in the PLA phase and using ADR improved its dispersion and reduced the PBAT droplets size. Simultaneous use of NCh and ADR increased the storage modulus from 2930 to 3222 MPa and reduced the difference in glass transition temperature of the two phases. Rheological assessments demonstrated shear thinning behavior across all blends, and at higher NCh levels, a solid‐like response was induced. Young's modulus of the simple blend in the presence of NCh (1 phr) and ADR (0.5 phr) increased from 1358 to 1500 MPa. However, increasing the NCh level from 1 to 3 phr caused a decrease in elongation at break from 135% to 75%. The shape memory performance test showed that NCh reduced shape fixity (SF) and shape recovery (SR) by inducing stress concentration. However, the addition of ADR improved SF (90%–95%) and SR (95%–99%) through better interfacial adhesion. This study provides a foundation for optimizing biodegradable nanocomposites with tailored properties for sustainable biomedical uses and active packaging.