Slow crack growth and impact mechanisms in polyethylene

The development of pipe grades requires the careful balance of several mechanical properties, of which two of the most important are the resistance to slow crack growth and rapid crack propagation. In the present paper, small scale tests are presented, which enable the rapid assessment of these properties. These development tools have been shown to correlate reasonably well with the more common industrial test methods for slow crack growth and rapid crack propagation resistance. In addition, these techniques have been used to develop an understanding of how molecular structure relates to properties, and this provides a framework within which the structural requirements of property balance can be discussed. PRCPA/1532 (C) 1998 The Institute of Materials.