Structure-property relationship of polyurethane ionomer

Polyurethane (PU) ionomers were prepared using various types of polyol (PTAd, PCL, PTMG, and PPG) and isocyanate (MDI, HDI, and IPDI), together with different extender (DMPA) contents, degree of neutralization, and number average molecular weight (M_n) of polyol. Modulus (E), strength (_b), and glass transition temperature (T_g) significantly increased with the increased amount of extender and extender neutralization. Among three of the iocyanate used, PU from MDI gave the highest modulus, strength, andT_g. With regard to theM_n of PTAd (600, 1000, 2000), PU from PTAd 600M_n gave the highest modulus, strength, andT_g, due probably to the highest hard segment content and phase mixing. On the other hand, PU from PTAd 2000M_n gave significantly improved strength over PTAd 1000M_n, and the highest elongation. The results were interpreted in terms of soft-segment crystallization, and soft-hard phase separation, which was concluded from the lowered softT_g.