Tensile deformation mechanism of polyamide 6,6/SEBS-g-MA blend and its hybrid composites reinforced with short glass fibers

Short glass fiber (SGF) reinforced polyamide 6,6 hybrid composites toughened with maleated styrene-ethylene butylenes-styrene (SEBS-g-MA) elastomer were prepared by compounding and subsequent injection molding. The hybrids were reinforced with 5, 10, 15, 20 and 30 wt% SGF. The matrix of the hybrids consisted of 80 wt% PA6,6 and 20 wt% SEBS-g-MA. Dilatometery was employed to characterize the deformation mechanisms of tough PA6,6/SEBS-gMA 80/20 blend and its hybrid composites under uniaxial tension. Dilatometric responses showed that both cavitation and shear yielding occur in PA6,6/SEBS-g-MA 80/20 blend during deformation. And the cavitation deformation prevailed over shear yielding in this blend after the initial elastic deformation. Moreover, the volume strain was observed to increase considerably with increasing SGF content for the hybrids investigated. SEM examination revealed that microvoids originated from the debonding of glass fiber from the PA6,6 matrix were responsible for the cavitation strain in the hybrids. Consequently, cavitation deformation predominated over shear yielding in hybrids.