Polymer Particles with a Low Glass Transition Temperature Containing Thermoset Resin Enable Powder Coatings at Room Temperature

Epoxy-based powder coatings are an attractive alternative to solvent-borne coatings. Here, in-house synthesized low glass transition temperature (Tg) particles containing epoxy resin and poly(methyl methacrylate) formed coatings at room temperature upon impact with a surface. Suspension polymerization was used to prepare particles as a function of diglycidyl ether of bisphenol A (DGEBA) and methyl methacrylate ratios. Higher incorporation of DGEBA decreased the Tg to below ∼20 °C and eliminated the need to heat the particles and/or aluminum substrates to form coatings. Using an electrostatic powder coating apparatus, a ∼ 70% particle deposition efficiency was achieved on aluminum substrates heated to 200 °C, whereas, at room temperature, high-speed single particle impact experiments proved that particle bonding occurred at a critical velocity of 438 m/s, comparable to commercial cold spray technologies. The in-house synthesized particles used in this study hold potential in traditional and emerging additi...