FRACTURE-BEHAVIOR OF RUBBER-TOUGHENED POLYMER BLENDS

The fracture toughness of a core-shell rubber modified polycarbonate-copolyester blend was determined by using the J-integral approach. Single-edge notch bend specimens were tested at room temperature using a crosshead speed of 1 mm min-1. The resistance curve for the blend was not affected by specimen width, direction of crack growth with respect to mould-flow direction, and sidegrooving. Fractographic analysis suggested that the matrix debonded from the rubber particles thus relieving the triaxial stresses and enabling the matrix to yield more easily. The initiation of crack growth in the J-tests was observed to occur shortly after the onset of non-linearity in the load-deflection curve. Consequently, an attempt was made to describe fracture in this blend by using linear elastic fracture mechanics.