Impact fracture mechanisms in polymer blends: Rubber‐toughened nylon

Abstract

Abstract The impact fracture mechanisms of rubber‐toughened nylon are analyzed by measuring the energy dissipated in several different processes during notched fracture. An energy balance is thus established for the impact fracture. The stress‐whitened zone is shown to be the energy dissipation zone, having an energy dissipation density of 5.30 cal/g. About 25% (i.e., 1.44 cal/g) of the impact energy is dissipated by matrix crazing. About 75% (i.e., 3.86 cal/g) is dissipated as heat by matrix yielding, causing a temperature rise of 9.1 °C in the energy dissipation zone. Surface energy storage on the fracture surfaces is negligible (i.e., 1.45 × 10 −5 cal/g). During matrix yielding, about 12% of α‐triclinic nylon crystals is transformed into pseudohexagonal crystals.