Tests for developing gas pipe resins

Abstract

The three major requirements for a gas pipe resin are: the minimum required strength (MRS) to resist ductile failure; excellent resistance to slow crack growth (SCG); and resistance to brittle fast fracture as exhibited by a low S4 critical temperature T _c. In developing a new PE resin, it is necessary to consider many variables, including the catalyst, type of reactor and the parameters of reactor operation. Tests for screening the effects on these mechanical requirements of this multitude of variables should be rapid and relatively inexpensive. Accelerated test methods available to industry for the development of PE 100 resins for gas pipes are reviewed. The emphasis is on the use of accelerated polyethylene notch tests (PENT) to measure the resistance to SCG and a Charpy impact test to predict T _c.