Enhancing Graphite Nanoplatelet Dispersion in PP Composites via Chemical Pretreatment for Cost‐Effective Packaging Applications

Polypropylene (PP) suffers from limited thermal stability and impact resistance, restricting its application in demanding environments such as cold‐chain logistics. PP nanocomposites reinforced with untreated (Un‐GnP) and pretreated (Pre‐GnP) graphite nanoplatelets were prepared to investigate the role of filler structure and surface chemistry. The pretreatment employed ice‐bath‐assisted ultrasonication to improve GnP exfoliation and dispersion within the PP matrix. Differential scanning calorimetry and X‐ray diffraction confirmed that GnPs acted as heterogeneous nucleating agents, enhancing crystallinity. Thermogravimetric analysis showed that Un‐GnP improved thermal stability, while defect‐rich Pre‐GnP reduced it. Dynamic mechanical and impact tests revealed a trade‐off between stiffness and toughness: Un‐GnP increased rigidity, whereas Pre‐GnP enhanced flexibility and low‐temperature impact strength. These results highlight that controlling GnP structure enables tailoring of PP nanocomposites, with Pre‐GnP composites showing promise for cold‐chain pallet packaging, where toughness under low temperatures is critical.