The morphology of crazes in polystyrene

Abstract

Thin sections of pre-crazed bulk specimens of polystyrene and thin sections containing crazes which were obtained by straining fresh films of polystyrene have been examined in the electron microscope. The use of reinforcing impregnants, a cold stage or a diamond knife was not required for ultramicrotomy. The microstructure of crazes in polystyrene has been shown in the later stages of craze deformation to consist of a well-defined fibrillar structure. The fibrils have a characteristic diameter of 200 to 400 Å and in the electron microscope the fibrils exhibit a beaded contrast. The beaded contrast can be considered as evidence for the existence of a domain structure in amorphous polymers. Some preliminary observations of the structure of crazes formed by straining in the electron microscope and some observations on the fracture surfaces of crazes are also reported.