Weathering Effect on Virgin Polyethylene and Polyethylene Coated with Polyamide/Nanosilica Composite Coating

Polyethylene film coated with polyamide/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 polyethylene film induced by accelerated ultraviolet exposure were studied by monitoring the changes in mechanical properties, carbonyl index, infrared effectiveness, and visible light transmission. The effect of polyamide/nanosilica composite coating on the durability and optical properties of polyethylene substrate was determined after 200 hrs and 500 hrs of ultraviolet exposure. Ultraviolet weathering has resulted significant reduction of visible light transmission of nanocomposite coated polyethylene film after 500 hrs of ultraviolet weathering. The mechanical properties of coated and uncoated polyethylene film were tremendously affected by ultraviolet exposure. Polyethylene coated with nanocomposite coating layer showed higher strength loss rate compared to uncoated polyethylene film. The surface protective coating of polyamide/nanosilica composite accelerated the photodegradation rate of polyethylene film. This photodegradation effect was evident with the increasing of composite coating thickness and nanosilica content in polyamide/nanosilica coating material. There was no effect of weathering to the infra-red effectiveness of both coated and uncoated polyethylene film.