63. Impact of Exposure Conditions on the Morphology of Polyethylene by Compact NMR
This current work reviews the potential of compact NMR for monitoring and quantifying morphological changes in PE exposed to elevated temperatures and/or contact with different solvents. To prove the reliability of compact proton NMR relaxation measurements, the results are compared with data from conventional high-field proton wide-line NMR spectroscopy, DSC, and FTIR spectroscopy. It could be shown that simple, static proton relaxation measurements garner detailed information about the exposure-induced morphological changes through the quantification of phase composition and chain dynamics. Moreover, the NMR method has a key advantage over other methods, because the chain mobility of the soft amorphous phase is a very sensitive microscopic parameter under exposure conditions. The various presented examples and the good agreement of the NMR results with those of other analytical methods show that low-field NMR is a promising option for in-situ aging studies.