فهرست نشریات علمی دسترسی آزاد ایران

This project mainly aims to synthesize a graphitic carbon nitride/carbon dots (g-C3N4/CDs) nanocomposite as a UV stabilizer to protect eco-friendly epoxy coatings exposed to UV rays and to avoid color change. To achieve this, using the pyrolysis of aqueous mixture of 1.8 g urea and 2.1 g citric acid, carbon dots were produced by a microwave-assisted method. Then, by adding 18 g melamine powder to the mixture and pyrolysis of it once again, g-C3N4/CDs nanocomposite was synthesized. By loading g-C3N4/CDs (CNCD) 0, 0.5, and 1 wt% into the epoxidized soybean oil-based epoxy (EP) resin matrix, EP/CNCD coatings were created. The results suggested that the EP/CNCD coatings (0.5 wt% and 1 wt%) exhibited fluorescence emission at 454 nm, strong absorption at 225 nm, 285 nm, and 345 nm wavelengths, and approximately 93-98% UV blockage at 315-400 nm. EP/CNCD 1 wt% showed more intense fluorescence emission, UV absorption, and UV blockage than the other samples. The morphological studies revealed that the photodegradation and surface roughness of EP/CNCD 0 wt% led by exposing the coatings to UV radiation (500 h, 60 ºC) were higher than those of the coatings containing nanofiller. The data from colorimetric analysis marked that EP/CNCD 0 wt% evinced the maximum color changes(∆E = 16.60) caused by exposure to UV among other coatings. The results of the pull-off adhesion strength test proved that loading CNCD (0.5 and 1 wt%) into the resin matrix improved the adhesion strength of the coatings before and after UV exposure.