Incorporating Epoxy and Amine into Poly(Methyl Methacrylate) for a Crosslinkable Waterborne Coating

The global market for waterborne coatings will continue to grow because alternative solventborne coatings emit environmentally hazardous volatile organic compounds (VOCs). However, most waterborne coatings are softer than solventborne crosslinked thermoset coatings because they feature thermoplastic polymer dispersions. To overcome these challenges, in this thesis we suggest a novel crosslinkable aqueous dispersion system that incorporates epoxy and amine particles into poly(methyl methacrylate) (PMMA); the particles will react when water (the solvent) evaporates, offering a potential one-component (1K) reactive system. Emulsion polymerization was used to synthesize the particles with the help of surfactants. Epoxy and amine particles were successfully incorporated during the synthesis of PMMA and formed a two-component (2K) aqueous dispersion. In this process, a non-ionic surfactant, Triton X405 (TX405), was used to prevent interactions with the amine particles. Nuclear magnetic resonance (NMR) was used to determine the actual incorporation ratios of epoxy and amine and we found an epoxy incorporation plateau. Dynamic light scattering (DLS) was used to determine the particle size distributions and a uniform distribution was observed. The pendulum test and the pencil test were used for coating hardness, which surpassed currently marketed waterborne coatings. The resulting aqueous dispersions could be cured under facile conditions, i.e., in air and at low temperatures. An increase in Tg was observed after crosslinking. Different mechanical properties were observed when the coatings were cured at different temperatures, 25°C, 70°C, and 100°C. These results suggest that we have successfully formed crosslinked coatings that contain our epoxy and amine incorporated particles, with mechanical properties comparable to the traditional solventborne coatings