Special features of the structure and properties of segmented oligodiene polyurethane elastomers with rigid segments of different structure

A study of the structure and viscoelastic properties of oligodiene segmented polyurethanes shows that the introduction of urea groups into a rigid segment containing urethane groups significantly increases the degree of segregation of the flexible and rigid segments, and that rigid domains of inhomogeneous structure are formed. The network of physical bonds with rigid domains as network points is capable of rearrangement and fracture when subjected to different mechanical loads and different temperatures, because of the difference in the energy of physical interaction in the rigid heterogeneous domains. The relaxational transitions appear on the thermomechanical curves and the plots of the tangent of the dielectric loss angle against the temperature, their positions depending on the concentration of the urea groups and the magnitude of the applied mechanical load.