Evolution of structure and properties in fiber formation from a thermoplastic polyester‐polyether segmented copolymer

Process‐structure‐property relationships in the formation of an elastic fiber from a melt of segmented polyester‐polyether copolymers are described. The “soft” segment, polyethylene oxide, is modified to prevent its crystallization at use temperatures. Features of the polymer related to phase separation of the soft segments and the crystallizable “hard” segments are discussed. An “ideal” morphology of such a thermoplastic elastomeric fiber that would maximize its recoverable extension is defined, and a path toward its realization in a melt spinning process is described.