Development of light filter film from neutron induced track-etch polymer

Abstract

This research work aimed to develop the light filter film from neutron induced track-etch polymer. Locally-available polycarbonate plastic sheets for sunshade were irradiated with neutrons from radioisotope source, Californium-252 (252Cf). Neutrons interacted with hydrogen atoms in polymer molecules and induced a latent of proton tracks in the polymer. The tracks can be made visible upon etching in a basic solution. This study used a PEW solution which composed of 15% KOH, 40% ethanol and 45% water. The polymer containing proton tracks was analyzed for track density and track diameter. Light transmission properties in three regions, i.e. ultraviolet, visible light and infrared, were tested using SD2400 apparatus in order to evaluate filtering and diffusing properties. Additionally, variations in etching temperature and etching time were studied in order to evaluate proton track diameter distribution. Results showed that the filtering efficiency of track-etched polycarbonate film with track density of about 3.04 x105 – 1.11 x106 tracks/cm2 increased by 5 - 15 % in the visible light region and 1 - 12 % in the infrared region compared with normal polycarbonate sheet. Furthermore, the filtering efficiency in the ultraviolet region was 100% due to the inherent property of polycarbonate sheet. Finally, study of infrared light diffusion property using a laser pointer beam revealed 1 - 3 folds increase in infrared light diffusion. It can be concluded that the proton track-etched polycarbonate plastic sheets were suitable to be used as a light diffuser.