GLASS-TRANSITION AND MELTING BEHAVIOR OF POLY(ETHER-ESTER) MULTIBLOCKCOPOLYMERS WITH POLY(TETRAMETHYLENE ISOPHTHALATE) HARD SEGMENTS

The glass transition and melting behavior of poly (ether-ester) multib lock copolymers with poly(tetramethylene isophthalate) (PTMI) hard seg ments and poly(tetramethylene oxide) (PTMO) soft segments are studied by differential scanning calorimetry (DSC) and small- and wide-angle x -ray scattering (SAXS and WAXS). Thermodynamic melting parameters for the PTMI homopolymer are estimated by WAXS and from the dependence of melting point on crystallization temperature. The melting behavior of PTMI is characterized by dual endotherms which are qualitatively repre sentative of the original morphology, although reorganization effects are present. The composition dependence of the glass transition temper ature parameters after rapid quenching from the melt are well describe d by mixed phase correlations for copolymers in the range 30-100 wt % hard segment. Combined with SAXS characterization at melt temperatures , a single phase melt is suggested in these materials which extends to temperatures below the hard segment melting point. (C) 1994 John Wile y & Sons, Inc.