Fracture - RCP # 2004 Milan
The three major requirements for a gas pipe resin are (1) the MRS , (2) excellent resistance to slow crack growth[SCG] and (3) resistance to brittle fast fracture as exhibited by a low S4 critical temperature,[Tc]. In order to develop a new PE resin, it is necessary to investigate many variables involving the catalyst, type of reactor and details in the operation of the reactor. The tests for screening the effects of this multitude of variables should be rapid and relatively inexpensive. This paper describes test methods used by a major resin producer in order to develop a PE 100 resin for gas pipes. The emphasis will be on the use of accelerated PENT tests to measure the resistance to SCG and a Charpy impact test[PAC] to predict the S4 critical temperature[Tc]. The fundamental basis for the correlation of the Tc with the Charpy energy will be presented.