Optimization of Waterborne Poly(Urethane-Acrylate) Nanoemulsions Based on Cationic Polymerizable Macrosurfactants with Different Hydrophobic Side Chain Length

Abstract

In situ surfactant-free emulsion polymerization can help avoid the utilization of harmful co-solvents and surfactants in the preparation of waterborne poly(urethane-acrylate) (WPUA) nanoemulsion, but the solid content is extremely limited, which will affect the drying rate and film-forming properties. The utilization of polymerizable macrosurfactants can overcome the above problems. However, the research on cationic polymerizable macrosurfactants is extremely scarce. In this work, cationic dimethylaminoethyl methacrylate-b-alkyl methacrylates block copolymers (PDM-b-PRMA) with terminal double bonds and different hydrophobic side chain (HSC) lengths were fabricated via catalytic chain transfer polymerization (CCTP). HSC length of PDM-b-PRMA played an important role in the phase inversion, morphology, rheological behavior of WPUA nanoemulsions, as well as the comprehensive performance of WPUA/PDM-b-PRMA films. Polymerizable PDM-b-PBMA macrosurfactant had smaller molecular weight, lower surface tension and colloidal size than the random copolymer (PDM-co-PBMA) by traditional free radical polymerization. It was easy for PDM-b-PRMA to orientedly assemble at the oil/water interface and provide better emulsifying ability when the carbon number of HSC was four. Compared with WPUA/PDM-co-PBMA, WPUA/PDM-b-PBMA had a smaller particle size, stability and better film-forming properties. This work elucidated the mechanisms of HSC length in the fabrication of cationic PDM-b-PRMA and provides a novel strategy to prepare cationic WPUA of high performance.2 of 17 have [17] developed a poly(urethane-acrylate) (PUA) with enhanced ionic conductivity and excellent mechanical properties.PUA comprised the advantages of both polyurethane and acrylic polymers, and has been widely used in coatings, adhesives, and surface treatments [17,18]. Up to date, researchers have developed the focus of PUA research into waterborne poly(urethane-acrylate) (WPUA) to reduce the utilization of organic solvents, including anionic, cationic, and nonionic WPUA [19,20]. Heretofore, anionic WPUA has been extensively investigated [21][22][23][24][25]. Fei et al. [26] have used pentaerythritol triacrylate and hydroxyethyl acrylate as cross-linker to fabricate WPUA microemulsions, which was able to increase the mechanical properties and water resistance of cellulose fiber-based paper. Hou et al. [27] have prepared a waterborne anionic alkoxysilane-terminated polyurethane dispersion, which exhibited mechanical properties and excellent freeze-thaw stability.Compared with anionic WPUA, cationic WPUA displays better adhesion to anionic substrates such as cellulose fiber paper, glass and leather, etc. [28][29][30]. However, investigations on cationic WPUA are relatively rare to date [31,32]. Sheng et al. [33] have obtained WPUA with long-chain hydrophobic alkyl structure by radical polymerization of stearyl acrylate with double bond end-capped WPU, which has been used for water repellents. Heretofore, several approaches have been adopted to prepare WPUA, such as phys...

Preparation and properties of soap‐free emulsion of polyacrylate grafted by polyester with highHEMAcontent

“…4 Water-based coatings have gradually replaced solvent-based coatings because of rich sources and the advantages of water-green, environmentally friendly, and non-polluting dispersion media. [5][6][7] The waterborne acrylates also have been developed rapidly, which are mostly divided into three categories: water-soluble, emulsion, and waterdispersed. [8][9][10] Acrylate emulsion is prepared by emulsion polymerization process, which is an environmentally friendly product with high molecular weight, good physical properties, low system viscosity, fast drying speed, and easy cleaning.…”