Preparation and characterization of UV-curable waterborne polyurethane using isobornyl acrylate modified via copolymerization

Abstract

Improving the properties of waterborne polyurethane (WPU) is an imperative yet high-demand step in the application of WPU in industry. The UV-curing technique is an effective way to enhance the application properties of WPU. Herein, a UV-curable WPU emulsion was prepared by mixing isobornyl acrylate (IBOA), pentaerythritol triacrylate (PETA) and methyl methacrylate (MMA) with a commercially available WPU emulsion. With the introduction of the IBOA, the viscosity of the IBOA-modified WPU (IAWPU) emulsion decreased, and the particle size increased. The IAWPU emulsion was stable for more than 6 months. The resulting IAWPU film restricted the movement of the segment by the rigid ring structure of IBOA. Meanwhile, IBOA also leads to an increase in the crosslinking density of the IAWPU films. The resulting IAWPU films had great water resistance, exhibiting a higher contact angle and lower water absorption than pure WPU. The tensile strength of the IAWPU film is up to 13.52 MPa, which is 14 times higher than the 0.9 MPa of pure WPU films. This work demonstrates that IBOA can more effectively improve the water resistance and mechanical properties of WPU through UV-curing technology.