Thermoplastic polyurethanes: synthesis, fabrication techniques, blends, composites, and applications

Thermoplastic polyurethanes (TPUs) have attracted increasing attention from the scientific and industrial communities due to their rich chemistry and wide fabrication techniques, which open up a vast field of application. Incorporating other polymers or fillers in TPU composition further expands TPU applicability. TPU blends and composites have been explored in medicine, agriculture, textiles, electronics, aeronautics, food packing, sensors, and automobiles. Soft and hard segments of different compositions have been combined to produce TPUs with specific properties, such as soft touch, elasticity, transparency, impact strength, chemical resistance, and elastic memory. Although petroleum-based precursors are still the most applied, green sources of diisocyanate, polyol, and chain extenders have been increasingly exploited. This review first addresses the fundamental chemistry, synthesis, fabrication techniques, and structure of TPUs and further compiles works on TPU blends and composites.