Mobile NMR for Analysis of Polyethylene Pipes

NMR relaxometry is a suitable tool to determine the morphology of semi-crystalline polymers by its ability to discriminate between rigid, mostly crystalline and soft, usually amorphous material. The NMR-MOUSE◦R (nuclear magnetic resonance mobile universal surface explorer) was explored in this work to supply morphological data of poly(ethylene) pipes nondestructively. PE-100 pipes were investigated in the new state, after squeezing them flat, and after annealing well below the glass temperature. Furthermore, the change in morphology induced by a pressure load from the inside and a point load from the outside was investigated as a function of depth, and the morphology change across a welding line was imaged. A shear-band was detected by destructive high-field NMR imaging in an area of severe deformation of a pipe, where an anomalous depths profile was observed by the NMR-MOUSE. These results demonstrate that the NMR-MOUSE is a suitable tool for non-destructive state assessment of polymer pipes on the basis of laboratory reference data.