Environmental stress cracking resistance of polyethylene: The use of CRYSTAF and SEC to establish structure-property relationships

Nineteen commercial high-density polyethylene resins made with different polymerization processes and catalyst types were analyzed by high-temperature size exclusion chromatography and crystallization analysis fractionation. The information obtained with these characterization techniques on the polymer chain structure was correlated to environmental stress cracking resistance. Environmental stress cracking resistance increases when the molecular weight and concentration of polymer chains that crystallize in trichlorobenzene between 75 and 85 °C increase. Polymer chains present in this crystallization range are assumed to act as tie molecules between crystal lamellae.