1H NMR Tests on Damaged and Undamaged XLPE Samples

XLPE (Cross-linked polyethylene) samples were subjected to high voltage AC in a plane-plane configuration and the voltage was increased to a level such that discharge was observed across the surface of the test sample for durations up to 10hrs. Selected stressed samples together with virgin samples from the same manufactured batch were tested using NMR (Nuclear Magnetic Resonance) spectroscopy. Specifically,
¹
H NMR spin-lattice (T
₁
) and spin-spin (T
₂
) relaxation time measurements were employed to examine potential changes in the chemical bonding of undamaged and damaged XLPE samples. Preliminary data show that there may be a moderate increase in the T
₁
and T
₂
values of the damaged samples in comparison to the undamaged ones. This raises the possibility that NMR can be a useful additional experimental tool in characterizing material degradation.