High solid and low viscosity waterborne polyurethane acrylate with excellent anti-corrosion and anti-bacterial performances

The design and preparation of great corrosion resistance and high-solid waterborne polyurethane dispersion with low viscosity is still a challenge in the field of the polyurethane industry. Herein, we developed a simple method involving a core-shell process to prepare a core-shell structured waterborne polyurethane acrylate dispersion (WPUAD). First, isobornyl acrylate, a derivative of natural product borneol, dihydroxylated by a thiol-ene click reaction was used to prepare oil-based polyurethane acrylate as prepolymer A (core) and waterborne polyurethane acrylate as prepolymer B (shell). Then, the core-shell WPUAD was obtained by mixing and emulsifying the two prepolymer at a certain ratio. The study reveals that the core-shell structured WPUAD not only has a low viscosity (~1330 mPa.s) but also holds a high-solid content (~ 60 wt%). At the same time, the highly solid WPUAD has excellent stability with no breast breakage even after more than 1 year of storage. In addition, various electrochemical measurements, water contact angles, and water absorption tests were performed to determine the anti-corrosive properties of the WPUAD-derived coatings. The results show that the WPUA coatings exhibit significantly enhanced anticorrosion with respect to the single prepolymer B derived coatings, which is attributed to their high cross-linking density resulting from the core-shell structure and the introduction of hydrophobic isobornyl acrylate. In addition, because of the introduction of the dihydroxylated isobornyl acrylate as chain extenders, the WPUA coating has great anti-bacterial adhesion properties with an anti-bacterial efficiency of 82.3 %. We believe that our work provides a generic preparation method to obtain a commercially available high-solid WPUAD with excellent anti-corrosion properties.