A systematic series of ‘model’ PTMO based segmented polyurethanes reinvestigated using atomic force microscopy

Effect of the degree of soft and hard segment ordering on the morphology and mechanical behavior of semicrystalline segmented polyurethanes

“…As the hard block length increases, in interlocking hard segment morphology develops, decreasing the average distance between hard domains, but increasing the thickness of the hard domain, which is confirmed by the SAXS studies. The development of a hard domain-continuous morphology upon increasing the hard segment size has been observed in other segmented polyurethanes [18,56]. The influence of this shift from a continuous, soft matrix to a hard, interlocking morphology directly influences the mechanical behavior of these multi-block polyurethanes.…”

“…AFM has been increasingly used as an alternative to transmission electron microscopy (TEM) for the visual interpretation of the nanostructure of segmented polyurethanes [56][57][58]. The surface morphology of these multi-block polyurethanes was imaged using tapping mode AFM.…”

Development and characterization of magnetorheological elastomers

“…Thus, for the imaged PUs, the microdomains appear lighter whereas darker regions correspond to the softer polyol phase. 16,17 Figure 21 shows the microphase of polybutadiene-PU. The existence of brighter areas demonstrated that the hard and soft segments did not possess homogeneous features and demonstrated phase separation in the PU elastomer.…”

Morphology and properties of thermoplastic polyurethanes with dangling chains in ricinoleate-based soft segments

“…Polyurethanes with a 70 wt% soft segment concentration (SSC) typically have non-spherical hard domains dispersed in the matrix of soft segments, while co-continuous phase morphologies have been postulated in the samples with 50 wt% SSC [6,7]. Reports also exist in the literature that demonstrate that if the hard segments can undergo crystallization, it may be possible to even develop spherulitic superstructures in such segmented systems [8][9][10][11][12]. In general, polyurethanes with 70% SSC are soft thermoplastic rubbers whereas those with 50% SSC are more commonly viewed as hard rubbers, both being of significant industrial importance.…”