Thermoplastic polyurethane (TPU) is any of a class of polyurethane plastics with many properties, including elasticity, transparency, and resistance to oil, grease and abrasion. Technically, they are thermoplastic elastomers consisting of linear segmented block copolymers composed of hard and soft segments.
The Chemistry of TPU:
TPU is a block copolymer consisting of alternating sequences of hard and soft segments or domains formed by the reaction of: (1) diisocyanates with short-chain diols (so-called chain extenders) and (2) diisocyanates with long-chain diols. By varying the ratio, structure and/or molecular weight of the reaction compounds, an enormous variety of different TPU can be produced. This allows urethane chemists to fine-tune the polymer’s structure to the desired final properties of the material. For example, a greater ratio of hard to soft segments will result in a more rigid TPU, while the reverse is also true.
Some use of TPU: