Stress‐cracking of polyethylene examined from the viewpoint of critical strain

Abstract

AbstractStress‐cracking in polyethylene has been examined from the viewpoint of critical strain based on a proposed theory for the formation of the cracks. Stress‐cracking under constant load and constant strain was determined experimentally at 60°C. on a 3.5 melt index high‐density polyethylene. A critical strain of 1.95% associated with a critical relaxation time of 90 min. was found for the sample. Good agreement was found between the theory and experiments made in Igepal CO 630. Some disagreements between the theory and experiments made in air were attributed to the rate of propagation of the cracks.