Maleopimaric acid-modified two-component waterborne polyurethane for coating applications

Maleopimaric acid (MPA), an important rosin derivative, was used to partially substitute isophthalic acid for the preparation of an anionic polyol (MPP) dispersion. The MPP dispersion was then applied to prepare a novel maleopimaric acid-modified two-component waterborne polyurethane (MPP-2K-WPU). The influences of NCO:OH molar ratio on the thermal properties, water absorption, surface free energy, and application properties of MPP-2K-WPU films were investigated. With increasing NCO:OH molar ratio, the thermal stability, pencil hardness, and ethanol resistance of MPP-2K-WPU films were improved, but the water resistance was enhanced firstly and then weakened. The surface free energy of MPP-2K-WPU films mainly depended on the dispersion interaction which was related to the structure of macromolecules. In addition, compared with the control sample of PP-2K-WPU(1.5:1) film, the MPP-2K-WPU(1.5:1) film exhibited improved thermal stability, water resistance, gloss, pencil hardness, and ethanol resistance. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133 , 43292.