抄録
Effects of molecular weight on the fracture formation of polystyrene have been studied in terms of the fracture surface morphology and the mechanical property. The fraction of mirror-like fracture surface increased with decreasing molecular weight. Samples for low-molecular weights were fractured as the mirror-like surface.
The craze width and the crack length were examined in relation to the molecular weight. The released energy per one crack propagation and the energy for crack formation per unit area were also estimated. It is concluded that high-molecular weight samples crack brittle at the maximum rate of fracture propagation (Vc). Low-molecular weight samples crack at the rate lower than Vc, giving rise to the mirror-like fracture surface.
