Orientierungsverhalten von segmentierten polyetherurethanen in abhängigkeit von der dehnung und den verwendeten lösungsmitteln

The solvent influence on two- phase structures resulting from drying films of segmented polyetherurethanes of different hard segment contents and molecular weights was investigated by infrared dichroism measurements of the orientational behaviour of the hard segments. A low density of physical crosslinking and/or minor association in solution leads to a lamellae structure resulting in an inhomogeneous distribution of stress at elongation. The formation of lamellae is impeded, if the solution shows pronounced formation of associates. Destruction of the lamellae can be monitored by studying the orientational behaviour for repeated deformations and by means of orientation-extension-hysteresis experiments. Stress-strain diagrams exhibit no contradictions to the discussed structural transformations by the influence of different solvents.