Effect of melamine modified cellulose nanocrystals on the performance of oil-immersed transformer insulation paper

It is generally believed that the service life of transformer oil-paper insulation is determined by the aging condition of transformer insulation paper. In order to further improve the anti-aging performance of transformer insulation paper, the cellulose nanocrystals (CNCs) modified by citric acid crosslinking and melamine amidation, were used to prepare the transformer insulation paper. The insulation paper containing modified CNCs was characterized with Fourier Transform Infrared Spectroscopy, X-ray diffractometry and Scanning Electron Microscopy. When the dosage of modified CNCs was 3.0 wt% at the beating degree of pulp of 35 °SR, compared with the reference insulation paper, the tensile index of insulation paper containing modified CNCs was increased by 17.30%, the AC breakdown strength in air and oil were increased by 12.95% and 40.28%, respectively. And the degree of polymerization of insulation paper containing modified CNCs was 50.50% higher than that of reference insulation paper at the aging time of 28 days. The melamine modified CNCs could improve the thermal aging performance of transformer insulation paper.