Thermoplastic elastomers by ''criss-cross''-cycloaddition polymerization

Segmented blockcopolymers were prepared via the condensation of telechelic precursors. ''Criss-cross''-cycloaddition of an aromatic aldazine with a diisocyanate gave telechelics with isocyanate functions at both ends. These prepolymers were reacted with alpha,omega-dihydroxytelechelic aliphatic polyethers. The cycloaddition-polymers served as hard segments with softening temperatures between 100 degrees C and 150 degrees C. The resulting segmented blockcopolymers exhibited microphase separation. Depending on the length and fractions of hard and soft segments, the mechanical properties varied from tough thermoplastics to soft elastomers with ultimate elongations above 800 %.