NMR IMAGING OF POLYETHYLENE PIPES

H-1 nuclear magnetic resonance (NMR) imaging techniques have been used to image the extrusion aid (EA) in polyethylene (PE) pipe samples. Th e resulting two-dimensional images show the distribution of EA within the pipe. EA is found to be uniformly distributed in a normal pipe. Ex amples of degraded pipes, due to exposure to extreme conditions, show migration of EA to the pipes' wall surfaces. NMR images of a normal pi pe and two examples of damaged pipes are presented. The imaging techni que and the results are discussed. (C) 1995 John Wiley and Sons, Inc.