Development of segmented poly(urethane-urea) elastomers and elastic fibers having good performance

Deformation mechanisms under large deformation and spinning theology of segmented poly(urethane-urea) were studied with the object of achieving ideal rubber elasticity, excellent elastic recovery and dye-affinity. The hysteresis behavior was verified by the fact that the irreversible transverce orientation of the hard segments occurred at low extension due to formation of spherulites structures. Copolymerization of hard segment was shown to improve hysteresis behavior and give rubber-like stress-strain relation. In order to improve elastic recovery at low temperatures. copolymerizing soft segment was found to be effective in preventing crystallization in its fixed state. The tertiary nitrogen group copolymerized in soft segment had the greatest effect on dye-affinity. Furthermore introducing tertiary nitrogen group into soft segments had the effect on elastic recovery at low temperatures. Spinning stress computed at the take-up point was found to be useful for describing the segmental orientation and the aggregate structure of the hard segment. Adequate spinning conditions were provided by simulation of the dry spinning process in relation to microstructure and orientation.