Abstract: In this paper, we analyzed the correlation between the slow crack propagation of PE and the single/multiple microstructural parameters including the number of molecular chains, molecular weight and distribution, content and distribution of short-chain molecules, and lamella thickness. Many studies indicated that the molecular weight and its distribution, content and distribution of short-branched chains exhibited a more significant correlation with the SCG resistance of PE pipes than other single microstructural parameters. The SCG resistance of PE pipes could be well measured with the structural parameters consisting of the multiple microstructural parameters.

Key words: polyethylene pipe, slow crack growth resistance, microstructure, tie molecule, molecular weight and distribution