Chemistry and Technology of Waterborne Polyurethanes

Waterborne polyurethanes (WPUs) are high-performance polymers where water is present as a primary solvent. The properties of WPUs are mainly dependent upon the chemical composition of the polymers’ building block or starting material. Mainly diisocyanate, polyols, diols, neutralizers, catalysts, and additives are used in the synthesis process of WPUs. Generally, polyurethanes are hydrophobic in nature, which ionic or nonionic hydrophilic segments can modify to enhance their hydrophilic nature to disperse in water. WPUs have appeared as a new technology for producing an eco-friendly material because of their nontoxic and nonflammable properties. They show good adhesion to different surfaces, such as polymer fibers and glasses, and also apply to coating one component and two components with high durability and corrosion protection. This chapter begins with the introduction of WPUs, and it also includes the chemistry of WPUs. This chapter also covers WPU-based nanocomposites. The chapter discusses four important applications of WPUs: printing, surface sizing treatment, coating, and adhesives. Finally, the chapter ends with a comprehensive conclusion.