By varying the ratio, structure and/or molecular weight of the reaction compounds, an enormous variety of different TPU can be produced.
For an immiscible TPU, the loss modulus spectrum typically shows double peaks, each of which is assigned to the Tg of one component.
This so-called phase separation between both blocks can be more or less important, depending on the polarity and the molecular weight of the flexible chain, the production conditions, etc.
These "pseudo crosslinks", however, disappear under the effect of heat, and thus the classical extrusion, injection molding, and calendering processing methods are applicable to these materials.
TPU has many applications, including automotive instrument panels, caster wheels, power tools, sporting goods, medical devices, drive belts, footwear, inflatable rafts, fire hoses, buffer weight tips and a variety of extruded film, sheet and profile uses.
[2][3] TPU is also a popular material found in flexible outer cases of devices like mobile phones and keyboard protectors.
Plant-based bio TPU has been developed for green thermoplastic elastomer applications by BASF, Merquinsa-Lubrizol and GRECO, marketed as Elastollan N, Pearlthane ECO and Isothane respectively.