Optical analysis of polycarbonate – Lead nitrate composite films for UV-A shielding applications

Abstract

Due to global warming and ozone depletion in the atmosphere, protection for human beings from UV radiation becomes necessary. It is possible to shield a selective part of the solar light falling on the earth’s surface by using polymeric composite materials. In this work, polymeric composite films have been prepared by using polycarbonate as the host matrix and lead nitrate as filler. Different filler levels, equal to 0, 5, 15, 25, 35, and 50 weight percentages (wt%) of lead nitrate are dispersed in polycarbonate by ultrasonication, followed by solution casting. The prepared films are characterized by using UV–Visible absorption (optical) spectroscopy, and the resulting spectra have been analysed. It is found that the absorption edge is shifted towards higher wavelengths (red shifted) as the filler level increases, and for the composites with filler levels greater than 15wt%, it is observed that there is strong absorption of the incident electromagnetic radiation in the wavelength range varying from 335 nm up to 375 nm (which is in the UV-A range). However, the transmittance in the visible region (400 – 700 nm) decreases from 87% down to less than 43%. The 15 wt% (FL) composite film has 64% of visible light transmittance. Hence, after exploring further improvements, it is a good candidate to replace glass in different applications like UV-A band filters, as well as Ultra-Violet (UV) protection windows, doors, face shields and safety visors of helmets.