Effect of Organic Montmorillonite on the Watertree Aging Properties of XLPE/OMMT Nanocomposite Dielectrics

In this different crosslinked polyethylene/organic montmorillonite (XLPE/OMMT) nanocomposite dielectrics were prepared by melt blending method to investigate the influences of organic montmorillonite types on the water-trees aging properties of the nanocomposites. Water-tree aging tests were performed on pure crosslinked polyethylene (XLPE) and XLPE/OMMT specimens using the water needle electrode method, the characteristics of the water trees were observed by microscopy and the growth length of water trees was statistically analyzed, and the chemical structure of the water trees before and after aging was characterized by fourier transform infrared spectroscopy (FTIR). The test results show that the crosslinked network of XLPE and the well-dispersed OMMT3 lamellae create a complex three-dimensional hybrid structure that effectively inhibits the growth of water trees in XLPE/OMMT3 nanocomposite dielectrics. This structure improves the ability of the XLPE molecular chain to resist damage. In the water-tree region of nanocomposite dielectrics, the carbonyl index R and the hydroxyl (-OH) vibration peak both rise, indicating that water-tree aging is due to electrochemical degradation, while the chain breakage of XLPE/OMMT3 is less in the process of watertrees growth, showing excellent thermal and oxygen aging resistance.