Anionic Polymerization of Methylene Malonate for High-Performance Coatings

Abstract

Here, we demonstrate the anionic polymerization and the high reactivity of the novel monomer diethyl methylene malonate (DEMM). At room temperature and under atmospheric conditions, water and anionic functional groups (i.e., carboxyl, boronic, and phenol) quickly initiate DEMM. The polymerization of DEMM in water and the final molecular weight of the polymer were both demonstrated to be pH-dependent. Systematically, investigations were conducted to study the conversion rate of DEMM with various functional groups, and the polymerization was verified to occur with anionic groups using a carboxylate-initiated DEMM system. For coating applications, we also investigated a multifunctional derivative monomer called (DEMM)6 that is an oligomeric polyester of DEMM esterified with butanediol that contains on average six repeat units of reactive DEMM (commercially known as Forza B3000 XP). The incorporation of 15 wt % (DEMM)6 into latex containing methacrylate acid as a functional monomer yielded cross-linked coatings with a gel content of 76.25 wt % that had a 289% improvement in rub-resistance performance compared to controls (without (DEMM)6). This study provides a facile methodology to synthesize cross-linked latex coatings at room temperature.

High-Performance, UV-Curable Cross-Linked Films via Grafting of Hydroxyethyl Methacrylate Methylene Malonate

“…Recently, our lab has successfully incorporated a novel methylene malonate chemistry into thermoplastic polymers, including acrylic latexes to prepare high-performance coatings. 29 Our previous study verified the high reactivity of diethyl methylene malonate (DEMM) initiated by sodium methacrylate; we achieved an ∼89% conversion of DEMM to polyDEMM in 5 min under facile conditions (room temperature, in air, and in the presence of water). 29 The high reactivity and anionically polymerizable nature of DEMM enabled a fast and easy approach to graft methylene malonate onto polymers and surfaces with incorporated nucleophiles.…”

“…29 Our previous study verified the high reactivity of diethyl methylene malonate (DEMM) initiated by sodium methacrylate; we achieved an ∼89% conversion of DEMM to polyDEMM in 5 min under facile conditions (room temperature, in air, and in the presence of water). 29 The high reactivity and anionically polymerizable nature of DEMM enabled a fast and easy approach to graft methylene malonate onto polymers and surfaces with incorporated nucleophiles. In this study, we used a novel monomer, hydroxyethyl methacrylate methylene malonate (HEMA-MM, Figure 1), to modify conventional emulsion polymers and convert them to UV-curable polymers without the premature cross-linking observed with other approaches.…”

“…Methylene malonate chemistry enables the facile grafting of polymers onto nucleophiles (i.e., hydroxyl, carboxylate, borate, and phenolate groups) via anionic polymerization under ambient conditions. 29 Here, latex was synthesized using standard emulsion polymerization, and 10 wt % methacrylic acid (MAA) was incorporated to provide anionic carboxyl groups as initiators to polymerize DEMM. The pH value of the latex was modified to 6, above the pK a of MAA, in order to fully deprotonate carboxyl groups.…”

“…The synthesis of the UV-curable coatings using HEMA-MM chemistry was conducted, as displayed in Figure 3 and Figure S5. First, various amounts of HEMA-MM (0, 2.5, 5, 7.5, and 10 wt %) were added and covalently grafted to the latex particles via anionic initiation with the carboxyl group, 29 leaving an unreacted methacrylate group pendent on the particle surface. The covalent grafting of poly(HEMA-MM) to the carboxyl groups was verified using 13 C NMR via the identification of a covalent bond at 63 ppm (Figure S3).…”

Epoxy Resin-Encapsulated Polymer Microparticles for Room-Temperature Cold Sprayable Coatings

“…Powder coatings are extensively used in industrial applications to provide superior performance, durability, and surface protection. − To form a coating, a thin layer of fine powder is deposited onto a substrate, followed by softening, fusion, and curing at an elevated temperature. In comparison with conventional solvent-borne coatings and aqueous polymer dispersions, powder coatings offer distinct economic and environmental advantages, including avoiding the emissions of volatile organic compounds (VOCs), a reduced processing time, lower energy consumption during baking, and easy recycling of oversprayed powder. ,− All of these advantages have prompted the development of highly competitive powder coatings in the coating market; however, room for improvements remain …”