Weathering Effect on PE Coated with Thin Layer of PU/Nanosilica Composite

Polyethylene (PE) film coated with polyurethane/nanosilica composite with varying composition were prepared and then exposed to ultraviolet radiation for accelerated weathering studies. The chemical and physical changes on nanocomposite coated PE film induced by UV exposure were studied by monitoring the changes in tensile strength, tensile modulus, elongation, carbonyl index, and visible light transmission. The effect of polyurethane/nanosilica composite coating on the durability and optical properties of polyethylene substrate was determined after 200 hrs and 500 hrs of ultraviolet exposure. There is no significant change was observed on visible light transmission for nanocomposite coated PE film after 500 hrs UV weathering. The mechanical properties of coated and uncoated PE were tremendously affected by UV exposure. PE coated with 4 µm of nanocomposite containing 6 wt% nanosilica showed less tensile properties deterioration compared to uncoated PE film after UV weathering. The surface protective coating of polyurethane/nanosilica composite with 6 wt% nanosilica content reduced the photodegradation rate of PE due to its excellent thermal stability compared to PE.