Prediction of environmental stress cracking resistance in linear low density polyethylenes

Recently it has been shown that the strain hardening modulus (G_p) at 80°C can be used to predict the environmental stress cracking (ESC) resistance of polyethylenes. The advantage of using strain hardening to determine ESC resistance is that the data may be obtained relatively easily and quickly using simple tensile test equipment. In this article, the strain hardening modulus has been used to predict the ESC resistance of three grades of linear low‐density polyethylene. Unlike in the previous research, the measurements were conducted at room temperature enabling tests to be performed without the need of a temperature‐controlled oven. This was achieved by reducing the strain rate to increase the sensitivity of the technique and increasing the thickness of the specimens to improve the repeatability. The strain hardening modulus data were found to correlate well with the ESC results obtained from long‐term full notch creep tests and are consistent with the known molecular structure of the polyethylene grades. POLYM. ENG. SCI., 2008. © 2007 Society of Plastics Engineers