Impact fracture toughness of short glass fiber-reinforced polyamide 6,6 hybrid composites containing elastomer particles using essential work of fracture concept

Polyamide 6,6 (PA6,6) hybrid composites toughened with maleated styrene-ethylene butylene-styrene (SEBS-g-MA) and reinforced with 5, 10, 15, 20 and 30% short glass fiber (SGF) were prepared via melt blending followed by injection molding. The matrix blend of composites consisted of 80 wt.% PA6,6 and 20 wt.% SEBS-g-MA. The impact fracture resistance of injectionmolded PA6,6/SEBS-g-MA 80/20 blend and its hybrid composites was investigated. Drop weight Charpy impact test showed that the hybrids exhibit much higher notched impact strength than the PA6,6 polymer under various test velocities of 1-5 m s^-1. Tough PA6,6/SEBS-g-MA 80/20 blend was not broken under the test velocities employed. The Charpy test is not a good technique to characterize the impact fracture behavior of tough polymer blend. The impact fracture resistance of tough PA6,6/SEBS-g-MA 80/20 blend can be characterized successfully using the essential work of fracture (EWF) concept under a speed of 3 m s^-1. Moreover, impact EWF measurements indicate the specific essential fracture work of hybrids to decrease with increasing SGF content. The specific non-essential plastic work was absent in hybrids owing to glass fibers restricting shear yielding of the matrix of composites. © 2002 Elsevier Science B.V. All rights reserved.