STRUCTURE AND PHYSICAL-PROPERTIES OF SEGMENTED POLYURETHANE ELASTOMERS CONTAINING CHEMICAL CROSS-LINKS IN THE HARD SEGMENT

Two series of segmented polyurethanes, one containing 50% soft segment s and the other with 70% soft segments were synthesized. Chemical cros slinks were introduced through the hard segment in a controlled way. C hemical polyurethane networks were characterized by swelling. The effe ct of the degree of crosslinking on properties was examined. It was fo und that chemical crosslinks in the hard segment reduce the mobility o f the soft phase and destroy the crystallinity of the hard phase, but they improve heat stability of the hard domains. (C) 1998 John Wiley & Sons, Inc.