Polyurethane coatings are renowned for excellent wear resistance, chemical resistance, mechanical properties, and corrosion resistance among various types of coatings. They have balanced mechanical properties, moderate to high hardness, good flexibility, and impact resistance arising from its soft and hard structural components. PU is a block copolymer with alternating hard segments (small diols and isocyanate-derived carbamates) and soft segments (long-chain polyols) shown in Fig. 4.1. These segments are thermodynamically incompatible and phase-separate at the nanoscale [1, 2]. Among these segments, the hard segment acts as physical crosslinkers, contributing tensile strength, hardness, and tear resistance, while soft segment imparts flexibility and elongation to the PU performance [3]. The overall mechanical performance of PU coatings depends on a complex interplay between their chemical structure, the ratio of hard and soft segments, crosslink density, and the use of additives or nanofillers [4]. Recent research has focused on tailoring these parameters to enhance specific properties such as hardness, flexibility, and impact resistance. Understanding these properties and how to improve them are pivotal for developing coatings capable of meeting challenging environmental and operational demands.