Rheological characterization and morphology of nylon 1212/functional elastomer blends

The rheological characterization and morphological analysis of nylon 1212 toughened with a maleated triblock copolymer styrene-b-(ethylene-co-butylene)-b-styrene (SEBS-g-MA) elastomer were carried out. We found that the critical shear strain of nylon 1212 was higher than that of virgin SEBS-g-MA and the plateau modulus of the blends in the curves of a dynamic strain sweep test was larger than those of the virgin components. All of the curves of a dynamic frequency sweep test showed a second plateau in the low-frequency region, except those of nylon 1212 and the blend containing 10 wt % SEBS-g-MA. Furthermore, the positive deviation in the plots of G′ versus blend composition demonstrated that the blends were still immiscible, although the graft reaction improved the compatibility of the blends. According to the theory of phase transition, the phase-inversion point was predicted to be about 50 wt % SEBS-g-MA, which corresponded to the morphology analysis. Additionally, the yield stress behaviors and long-time relaxation behaviors of the blends were investigated. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009