The role of fast and slow processes in the formation of structure and properties of thermoplastic polyurethanes.

New multi-blocked thermoplastic polymers containing rigid polyurethane-urea and soft polydiethylene glycol adipate blocks have been synthesized. Basic features of their structure formation have been revealed. Three types of supramolecular organization have been found, which define the behavior of samples under heating and deformation conditions. The shape memory effect has been interpreted through the transition of one type of morphology to another. The variation of the functional characteristics of the material was addressed in the process of long-time storage at room temperature. The changes of physical-mechanical and thermodynamical properties of the materials were related to structural evolution within 60 months of storage. The competing role of crystallization and phase separation was proposed to explain the unusual mechanical behavior of the materials.