Essential work of Fracture and critical strain energy release rate analyses were used to investigate the effect of temperature (from 25 to -25 degreesC) and specimen ligament length on the fracture energy, obtained from an instrumented drop tower test, of two compatibilized nylon 6/ABS blends (40 and 25 wt% ABS) and the neat ABS. Three types of fracture were observed: ductile, mixed mode, and brittle. The essential work of fracture parameters were obtained by an analysis of the fracture energies for samples that Failed in a ductile manner. The dissipative energy density, u(d), was found to decrease with decreasing temperature for each of the three materials, while the specific limiting fracture energy, u(o), was found to be nearly invariant with temperature for the two blends but to decrease with decreasing temperature for the ABS. The critical strain energy release rate, G(IC), model gives an excellent description of the fracture energies of samples that failed in a brittle manner; G(IC) was Found to decrease as temperature was reduced. The yield stress, sigma (y), and the plane-strain critical stress intensity factor, K-IC, were also determined. The yield stress was found to be invariant with temperature, while K-IC decreases as the temperature is lowered. (C) 2001 Elsevier Science Ltd. All rights reserved.