Temperature plays the main role in oil-paper degradation.In order to study oil-paper aging mechanism

accelerated thermal aging experiments in laboratory were performed.Kraft paper and naphthenic mineral oil were thermally aged for 370 days at 90 ℃.The XRD under different aging conditions of insulation samples were periodically performed

the variation of supramolecular structure of the oil-paper with different aging conditions was investigated

and the kinetics of paper degradation was also discussed in detail.The results indicate that the degree of polymerization（DP） of the oil-paper is caused by breakdown of hydrogen and glycoside bonds

resulting in cellulose’s inter-or inner-molecular force weakening and activation energy of pyrolysis decreasing.The crystal areas of cellulose are destroyed

and the crystal grain size decreases

and the crystal type keep stable during paper aging.The decreasing of DP coincides with the second-order kinetic model

and the decreasing law of DP can be well explained by relative degree of crystallinity.