Chemical structure-physical property relationships in polyurethane elastomeric fibres; property variations in polymers containing high hard segment concentrations

Abstract

A series of linear polyether urethane elastomers has been prepared with soft segment (polyether) content ranging from 0 to 70.8 per cent. The polymers were wet spun; the mechanical and elastic properties of the resulting filaments were examined. Cross-sections of the filaments were examined under cross-polaroids. A macroscopically discernible phase change appears to be related to an inversion of stress-relaxation trends. Specific stress and elongation at break appear also to be affected by the same phase change; minor abnormalities of modulus and specific stress, inside a narrow variation of soft segment concentration, coincide with the appearance of spherulitic structure and birefringence. The elastic behaviour of the filaments is discussed and explained in terms of a physical structure consisting of soft and hard segment domains. © 1972.