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SynopsisA series of segmented ionene polymers based on the reaction of qw-bis(dimethy1 amino)polytetramethylene oxide with various dihalide compounds were investigated with respect to their structure-property behavior. The placement of quaternary ammonium ions and halide counterions along the polymer chains was varied by changing the molecular weight of the PTMO soft segment and the structure of the dihalide linking agent. The techniques of dynamic mechanical spectroscopy, thermal analysis, small angle X-ray scattering, and stress-strain behavior analysis were applied. For the case when the PTMO soft segment was amorphous, the ambient temperature properties of these materials displayed low modulus, high strength, and high elongation elastomeric behavior with tensile strength enhanced by the strain-induced crystallization of the PTMO. A high level of phase separation existed between the dihalide component relative to the PTMO soft segment. Due to the Coulombic association of the ionene species, these materials displayed many similarities to the segmented urethane ionomers. In particular, distinct domain structure was noted by SAXS, whose dimensional scale was similar to the segmented urethanes. It was also shown, however, that the driving forces for the microphase separation was caused by favorable electrostatic or Coulombic interactions in contrast to segment-segment incompatibility features as in the segmented urethanes.

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The structure and properties of polyisoprene-based telechelic ionomers having neutralized terminal sulfonate and carboxylate groups have been compared. In general, the mechanical properties of these materials suggest that metal sulfonates form stronger aggregates than the aggregates formed by metal carboxylates. This agrees with the results of previous workers who made similar comparisons for randomly substituted ionomers. Small-angle X-ray scattering data indicate that the periodic spacings between metal sulfonate aggregates are consistently higher than for the carboxylate ionomers, suggesting that the metal sulfonate aggregates may contain more ion pairs per aggregate than the metal carboxylate aggregates. The phase boundary between the ionic and nonionic regions is very sharp for both sulfonate and carboxylate ionomers.