SYNTHESIS AND CHARACTERIZATION OF ION-CONTAINING POLY(URETHANE-UREA-IMIDE) BLOCK-COPOLYMERS

Poly(etherurethane-urea-imide) (PEUUI) block copolymers containing a t ertiary amine have been synthesized by reaction of amine-terminated po ly(etherurethane-urea) (PEUU) prepolymer with 3,3,4,4-benzophenonetetr acarboxylic dianhydride (BTDA) followed by solution imidization. The a mine-terminated PEW prepolymer was prepared using poly(tetramethylene oxide) of molecular weight 2000 as soft segment, toluene diisocyanate (TDI), N-methyldiethanolamine (MDEA), and 4,4-oxydianiline (ODA). The PEUUI block copolymer was converted to ionomer by quaternizing the ter tiary amine of MDEA with different diacids and alkyl halides. Properti es of PEUUI ionomer films cast from solution were studied by infrared spectroscopy, differential scanning calorimetry, dynamic mechanical an alysis and stress-strain testing. The quaternization of PEUUI shifted the soft segment glass transition temperature (T-g) of PTMO to a lower temperature with subsequent development of hard segment ordering in c omparison to nonquatemized PEUUI. The morphological changes of PEUUI u pon quaternization were accompanied by dramatic improvements in mechan ical properties and dynamic modulus that was extended to much higher t emperatures. The mechanical properties and thermal transitions were fo und to depend on the nature of quaternizer, provided that the system e xhibited a two-phase interconnecting morphology. The improved mechanic al properties and lowered soft segment T-g of PEUUI ionomer samples we re due to increased hard domain cohesiveness caused by ionic interchai n interactions and aggregation of ionic groups.