New methods for checking divergences in the manufacturing of pe resins and ppipes: heological and physicochemical procedure for identity cards characterization

摘要

A manufacturing inspection procedrue for PE resins and pipes based on two new methods has bene developed.This procedrue should allow extending the detection further upstream of any manufacturing divergences tha tcould reduce the long term resistance of PE piping.The first of these two methods concerns the rheology of the material.It is based on the original model developed by Gaz de France at the beginning of htis decade and leads to a set of five parameters characterisitc of the behavior of the mateiral.the second mehtod relates to the appearance of slow cracking.Based on a modified SIS technique,it consists in determining a physicchemicla parameter which gives an image of the extent of entanglement of the macromolecules in the solid and thus the greater or lesser tendency to slow crackign of the studied mateiral.The overall procedrue permits to establish identity cards of the PEs under study.the final stage of this study is the transfer of these methods to the PE pipe and/or resin manufacturers.