Synergistic effects of Graphene Nanoplatelets and Joncryl ADR on the mechanical and thermal properties of PLA/POM nanocomposites

Poly (lactic acid) (PLA) is a bio-based polymer derived from renewable resources; however, its intrinsic brittleness and low ductility limit its wider application in engineering materials. In this study, the strength ductility balance of PLA was systematically improved through a multi-component design strategy involving polyoxymethylene (POM) blending, Joncryl ADR reactive compatibilization, and graphene nanoplatelet (GNP) reinforcement. A structured three-stage experimental approach was adopted: (i) screening PLA/POM blend ratios (20/80-80/20 w/w), (ii) optimizing ADR loading (0.2-1.2 wt%), and (iii) evaluating GNP reinforcement (1-5 wt%). The composites were fabricated via twin-screw extrusion and characterized using tensile testing, scanning electron microscopy (SEM), X-ray diffraction (XRD), and differential scanning calorimetry (DSC). The PLA40/POM60 blend significantly increased elongation at break from 2.6% for neat PLA to 12.3%, corresponding to a 4.73-fold improvement, although a slight reduction in tensile strength was observed. The incorporation of 0.4 wt% ADR effectively restored the tensile strength to ≈ 51.3 MPa while further increasing elongation to ≈ 14.0%, representing a 5.38-fold improvement compared with neat PLA. DSC analysis revealed an increase in crystallinity from ≈ 15.8% (neat PLA) to ≈ 22.2% for PLA40/POM60/ADR0.4, indicating enhanced structural organization after reactive compatibilization. Further reinforcement with 3 wt% GNP improved tensile strength to ≈ 52.0 MPa and elongation at break to 14.59%, corresponding to ~ 1.01× and 5.61× increases, respectively, relative to neat PLA. However, increasing GNP content beyond 3 wt% led to performance deterioration due to nanoplatelet agglomeration and reduced stress-transfer efficiency. Overall, the results demonstrate that the synergistic combination of blend toughening, reactive compatibilization, and nanofiller reinforcement provides an effective strategy for developing PLA-based nanocomposites with balanced mechanical and thermal properties. The developed materials show promising potential for applications in durable packaging and lightweight engineering components.