Effect of Ozone Aging and <scp>ZnO</scp> Doping on the Mechanical, Thermal, and Chemical Properties of Glass‐Epoxy Composites

ABSTRACT This study explores the effects of ozone exposure and ZnO doping on the mechanical, thermal, and chemical properties of glass‐epoxy composites. Composite samples were subjected to ozone aging under controlled conditions and were modified with 1%, 2%, and 4% ZnO contents. Tensile testing, FTIR, TGA, and DSC analyses were conducted to assess performance changes. Results showed that 700 parts per hundred million (pphm) ozone exposure enhanced tensile strength by ~12%, likely due to improved matrix–fiber interaction. In contrast, high ozone exposure led to polymer degradation and reduced mechanical performance. The highest tensile strength was observed in samples containing 2% ZnO under high ozone exposure, showing a 13.5% improvement over the unmodified composite, which indicates a clear synergistic effect between ZnO and ozone. Thermal analyses confirmed that ZnO improved thermal stability and increased glass transition temperature. FTIR results revealed that ZnO effectively reduced oxidative modifications induced by ozone, as indicated by the decreased intensity of –OH and C=O absorption bands. These findings suggest that tuning ZnO content and ozone exposure can improve the durability of glass‐epoxy composites.