Production and application of biochar in a UV radiation-curable epoxy paint as a substitute for graphite

Research on the use of sustainable fillers which promote improvements in the paints has been reported over the years. The present study investigated the production and characterization of a biochar produced from Pinus elliottii for application in an epoxy paint cured by ultraviolet radiation, comparing it with graphite, in proportions of 12.5 and 20 wt%. The Pinus elliottii sample was initially ground, and then submitted to physical and morphological characterization by field emission scanning electron microscopy (SEM) and X-ray diffraction (XRD). Later, the Pinus elliottii sample was subjected to pyrolysis at a temperature of 1050°C at a low heating rate (5°C/min). Biochar and graphite were separately incorporated into an epoxy UV-curable paint. The painted samples had their thickness measured and their mechanical and physical properties evaluated, namely gloss, hardness, bending, impact, contact angle with water, and exposure to salt spray. Biochar and graphite promoted a reduction in gloss and improved pencil hardness when incorporated into a UV-curable epoxy paint. In the salt spray resistance test, samples containing both biochar and graphite showed a slight delay in the beginning of the corrosion process. However, samples with biochar behaved better than samples with graphite in terms of blistering of the film in the incision region.