Sustainable poly(lactic acid) nanocomposites with chitosan-functionalized graphene oxide: Enhanced interfacial...

In this work, a novel GO-CS nanohybrid was developed using chitosan (CS) with a spherical microstructure, designed to enhance the compatibility of graphene oxide (GO) with the PLA matrix. PLA nanocomposites containing different loading levels of GO and GO-CS were prepared via solvent casting and systematically investigated for their thermal, mechanical, rheological, and microstructural properties, complemented by molecular dynamics simulation of interfacial interactions. The results reveal that the GO-CS hybrid enables significantly higher loadings (up to 2 wt%) while maintaining or even improving mechanical performance, in contrast to pristine GO which shows optimum properties only at very low loading (0.3 wt%). Molecular simulations confirmed the stronger interfacial interaction of GO-CS with PLA, attributed to the H-bonding facilitated by CS functional groups. Rheological analysis further showed that GO-CS reduces viscosity and elasticity, indicating improved processability, which is critical for scalable production. These findings demonstrate that effective interfacial engineering via spherical CS is a promising strategy to achieve a balanced combination of mechanical properties and processability in PLA-based nanocomposites, opening opportunities for applications in sustainable packaging and biomedical application.