Salt weathering effect of polymer coatings studied by positron annihilation spectroscopy

Abstract Deterioration of polymer coatings due to UV light and salt effects as a function of exposure time was studied by using positron annihilation spectroscopy. Doppler broadening energy spectroscopy (DBES) of annihilation radiation and positron annihilation lifetime (PAL) were measured as a function of positron incident energy (0–30 keV). A significant decrease in the S -defect parameter from DBES and the intensity of o -positronium from PAL was observed as a result of the UV and salt exposures. Salt significantly increases the deterioration of polymeric coatings under UV irradiation by a factor of 2. Direct correlation between the decrease in gloss and the decrease of S parameter from positron data is observed.