Structure and morphology of segmented polyurethanes: 4. Domain structures of different scales and the composition heterogeneity of the polymers

The morphology of polybutadiene containing polyurethanes has been studied by using small-angle lightscattering (SALS), small-angle X-ray scattering (SAXS), phase contrast microscopy and electron microscopy.Domain structures having sizes of 1000, 100 and 10 nm are observed within these samples and are explainedas the results of segregation on the molecular level, subchain level and segmental level, respectively. Thesephenomena are related to the molecular heterogeneity in chemical composition and average hard segmentlength. It has been found that because of the analogy in molecular structure with SBS block copolymers,segmented polyurethanes may form microdomains of soft and hard segments with more or less uniform sizeand regular arrangements in space