Thermoplastic Polyurethane Elastomers Temperature Dependence of Physical Properties

Thermoplastic urethanes can be regarded as linear, block copolymers of the (AB)_n type, the A block being considered the soft segment and the B block the hard segment.

This study was concerned with the temperature dependence of mechanical properties for thermoplastic urethanes based on polycaprolactone diols, 4,4-diphenylmethane diisocyanate (MDI) and 1,4-butanediol (BDO). The molecular weight of the polycaprolactone diol (A or soft segment) was varied independently, as was the relative concentration of the MDI/BDO hard (B) segment.

The resulting urethanes ranged from rubbery to hard and tough materials. Some of the urethanes displayed compatible behavior. Others displayed an incompatible behavior and were, thus, less temperature dependent.