POLYMERS BY CRISS-CROSS-CYCLOADDITION .7. SEGMENTED BLOCK-COPOLYMERS

''Criss-cross''-cycloaddition of 4,4'-diisocyanatodiphenyl ether and 4 -methoxybenzaldazine was used to synthesize alpha,omega-diisocyanato t elechelics of molecular weights between 1600 and 3900. These precursor s were reacted with different alpha,omega-dihydroxy functionalized ali phatic polyethers to produce segmented block copolymers in which the p recursors obtained by cycloaddition reaction provide hard segment doma ins embedded in a polyether soft segment matrix. The resulting materia ls were soluble in common organic solvents such as tetrahydrofuran and chloroform and were characterized by spectroscopic techniques (H-1-, C-13 NMR, IR spectroscopy) as well as gel permeation chromatography (G PC) for molar mass determination The block copolymers were molded in a hot stage press, and the resulting samples were characterized by diff erential scanning calorimetry (DSC), dynamic mechanical thermal analys is (DMTA) and stress-strain measurement. The materials with a hard seg ment fraction below 0.36 and a molecular weight above (M) over bar(n) = 90 000 were elastomers with ultimate elongations above 700%.