The Role of TiO₂ and ZnO Nanoparticles in Optimizing the UV Resistance, Thermal Stability, and Mechanical Properties of Polyethylene-Based Composite Materials

Polyethylene (PE) is susceptible to photo-oxidative degradation under ultraviolet (UV) irradiation, exhibits limited thermal/oxidative stability, and faces stiffness-toughness trade-offs. This work examines TiO₂ and ZnO nanoparticles-employed as bare and surface-modified fillers with a PE-g-MA compatibilizer-to optimize the UV resistance, thermal stability, and mechanical performance of PE composites. Composites were produced by melt compounding and solution casting. Accelerated UV weathering was performed, and specimens were characterized by FTIR carbonyl index, UV-Vis, TGA/DSC/DMA, and SEM/TEM; differences were evaluated using ANOVA. Coated TiO2⁄ZnO at 1 − 3 wt% delivered the best balance, increasing oxidative-induction time, raising TGA onset temperature, and elevating crystallinity and storage modulus while preserving tensile strength after aging. Surface modification suppressed photocatalytic discoloration and embrittlement, whereas compatibilization improved interfacial stress transfer. The improvements arise from UV attenuation, heterogeneous nucleation, and strengthened polymer-filler interfaces. The findings demonstrate applicability to industrial packaging and outdoor parts; limitations include agglomeration and viscosity growth at higher loadings.