INFLUENCE OF PROCESSING CONDITIONS ON THE MULTIPHASE STRUCTURE OF SEGMENTED POLYURETHANE

The multiphase structure of thermoplastic polyurethane elastomers is n ot only influenced by the chemical structure, but also by the processi ng conditions. The polymorphism of hard segment (HS) crystallites of a commercial polyurethane was investigated in dependence on the melt pr ocessing conditions using WAXS and d.s.c. The observed crystalline mor phology types are strongly influenced by the processing temperature. A nalysis of the results permits the assignment of HS crystallites of so -called 'type II' with high WAXS intensity to those melting above 220 degrees C. Additionally, the tensile strength was determined. These re sults related to the d.s.c. data allow to establish a processing-struc ture-property elation. (C) 1998 Elsevier Science Ltd. All rights reser ved.