Waterborne Polyurethanes: Chemistries and Applications

Polyurethanes have long been known mainly for adhesives and coatings that exhibit high toughness, abrasion resistance, enhanced aesthetics, and durability. The performance standard for high durability coatings has historically been set by solvent-based polyurethanes. Alternative technologies based on waterborne polyurethane systems have been developed, however, as a result of environmental concerns for low-volatile organic compounds alternatives and less solvent exposure. Waterborne polyurethanes, which form films at ambient temperature, can be formed into a variety of applications with little to no co-solvent. They have great adherence to a variety of surfaces, including glass and fibres made of polymeric materials. These eco-friendly polymers are neither combustible, poisonous, or cause any waste products or air pollution. The polyurethanes are typically hydrophobic and insoluble in water. They must therefore be altered, for example, by adding ionic groups and/or non-ionic hydrophilic regions to the polymer structure, in order to be dispersed in water. WPUs have a number of exceptional qualities, such as good applicability, excellent abrasion resistance, and low viscosity at high temperatures, among others, which surely increased their use in biomedical disciplines such as medication loading and dressing for wounds. This has sparked an increased interest among researchers in creating new WPU with distinctive properties. Many processes and raw materials have been developed to prepare WPU. This chapter has examined several waterborne polyurethane types, synthesis methods, properties and applications.