Polymer Particles with a Low Glass Transition Temperature Containing Thermoset Resin Enable Powder Coatings at Room Temperature
Ind. Eng. Chem. Res., 2019, 58 (2), pp 908–916
Publication Date (Web): December 20, 2018
†Department of Chemical Engineering, University of Massachusetts Amherst, Amherst, Massachusetts 01003-9303, United States
‡Department of Mechanical and Industrial Engineering, University of Massachusetts Amherst, Amherst, Massachusetts01003-2210, United States
§ARL Center for Cold Spray, United States Army Research Laboratory, Adelphi, Maryland 20783-1138, United States
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 additive manufacturing applications.