Fracture characterization of PC/ABS blends: effect of reactive compatibilization, ABS type and rubber concentration

The fracture of thin (3.18 mm) and thick (6.35 mm) specimens of polycarbonate (PC), acrylonitrile-butadiene-styrene (ABS) and PC/ ABS blends with both standard and sharp notches was examined by standard Izod and single edge notch three point bend (SEN3PB) instrumented Dynatup tests. Ligament lengths were varied for SEN3PB samples and the corresponding fracture data were represented by plotting the specific fracture energy (U/A) as a function of ligament length (l). The slope of these plots was found to be closely related to both the Izod impact strength and the size of the process (or stress whitened) zones surrounding the crack surface. Significant morphology coarsening was seen in some PC/ABS (70/30) blends for thick (6.35 mm) injection molded parts; blends compatibilized with 1% of an SAN-amine polymer exhibited well-dispersed, stable morphologies. The effects of blend composition, ABS type, sample geometry, PC molecular weight, temperature, rubber concentration and reactive compatibilization on the fracture properties of these materials were examined. (C) 1999 Elsevier Science Ltd. All rights reserved.