Tensile Strength of Plastics below the Glass Temperature

Abstract

The times taken for two plastics, polystyrene and polyethyl methacrylate, to break under various constant loads are reported for both the glassy and rubbery states. A theory is presented which describes the strength properties of plastics in the glassy state. The theory predicts that the logarithm of the time taken for the sample to break is proportional to the applied load. Such behavior is actually found by experiment. The tensile data in the rubbery range are adequately represented by a theory previously developed for that region.