Reactive Mechanochemical in Situ Synthesis of Cu 2 O and ZnO Nanoparticles in Maleated Polyethylene: Structure–Property–Function Relationships

A solvent‐free reactive mechanochemical melt‐processing strategy was developed for the in situ synthesis of copper(I) oxide (Cu 2 O) and zinc oxide (ZnO) nanoparticles within a maleated low‐density polyethylene (mLDPE) matrix through the thermal decomposition of metal acetates under high‐shear conditions. The proposed approach enables simultaneous nanoparticle formation, dispersion, and stabilization in a single processing step. The structure, interfacial interactions, thermal behavior, mechanical properties, and antifungal activity of the prepared nanocomposites were investigated by XRD, FTIR, AFM, thermal analysis, and mechanical testing. XRD confirmed the formation of crystalline Cu 2 O and ZnO nanoparticles with an average crystallite size of 25 ± 1 nm at a loading of 5 wt%. FTIR revealed different interfacial interaction mechanisms, with Cu 2 O remaining mainly physically dispersed, while the Zn‐containing system showed evidence consistent with coordination interactions between Zn 2+ species and maleic‐derived carboxylate groups of mLDPE. Nanoparticle incorporation improved surface morphology, tensile properties, thermo‐oxidative stability, and resistance to fungal colonization compared with pristine mLDPE. Among the investigated systems, the ZnO‐containing nanocomposite exhibited the best overall performance. These results demonstrate that interfacial chemistry governs the structure–property relationships of mechanochemically prepared polymer nanocomposites and highlight reactive melt processing as a scalable route for multifunctional polymer materials.