Effect of UV Ageing on Thermo-Mechanical Properties of Ethylene-Vinyl Acetate Nanocomposite Encapsulant

Photovoltaic (PV) modules are used in outdoor and affected by ultraviolet (UV), heat and humidity which have high impact on the properties of the EVA encapsulant and cause yellowness, delamination and degradation of the material which further effects on the performance and service life of PV modules. This paper addresses the effect of UV aging of ethylene-vinyl acetate copolymer (EVA) with three different nano zinc oxide (n-ZnO) contents (0.05, 0.1, and 0.15 wt%) was performed in a xenon arc source chamber. Pure EVA, 0.05, 0.1, and 0.15 wt% of EVA/n-ZnO nano composites were prepared by solvent casting method using toluene as solvent. The prepared samples were exposed to UV light generated 0.51 W/m2 irradiance from a xenon lamp at 340 nm wavelength for 1000 hours. The effect of UV ageing on thermal, mechanical and electrical properties of EVA nanocomposite encapsulant has been investigated. Thermal conductivity was studied at room temperature (25°C) and at elevated temperature of 50 °C for before and after ageing samples. Tensile strength and elongation were conducted to check the mechanical properties after ageing. Water contact angle measurement was conducted to check the wettability of the encapsulants before and after ageing. It was observed that 0.1 wt% of EVA/n-ZnO nano composite retains better physical, mechanical and electrical properties.