Recent trends in environmentally friendly water-borne polyurethane coatings: A review

• Published in: The Korean journal of chemical engineering 2016, 33(2), 191, pp.388-400
• Main Authors: Noreen, Aqdas, Zia, Khalid Mahmood, Zuber, Mohammad, Tabasum, Shazia, Saif, Muhammad Jawwad
• Format: Article
• Language: English
• Subjects: Biotechnology; Catalysis; Chemistry; Chemistry and Materials Science; Industrial Chemistry/Chemical Engineering; Materials Science; Review Paper; 화학공학
• ISSN: 0256-1115; 1975-7220
• DOI: 10.1007/s11814-015-0241-5

Environmentally friendly waterborne polyurethane (WPU) coatings are used extensively due to their low VOCs emission than solvent based PU coatings. Additionally, WPU coatings have low temperature flexibility, pH stability, water resistance, superior solvent resistance, outstanding weathering resistance and desirable chemical and mechanical properties. This review provides an overview on the recent developments of WPU coatings and their value added applications in the coatings and paint industry. UV-cured WPU coatings provide an important class of green and ecofriendly coatings with outstanding mechanical properties and rapid curing system. Hyper-branched polyurethanes (PUs) show interesting properties, such as high solubility, reactivity and good rheological behavior owing to multiple end groups, compact molecular structure and diminishing chain entanglement. Inherently, WPU coatings have reduced stiffness and mechanical strength that can be increased by the addition of nanoparticles, like Ag, Cu, TiO 2 , SiO 2 and many more. Fire retardants, commonly phosphorous, are incorporated in the WPU structure to increase the flame retardancy of WPU coatings.