矿物油-天然酯混合绝缘油减缓绝缘纸热老化速率机理的XPS研究

摘要

以矿物油-天然酯混合绝缘油及25#矿物油为研究对象,对比了两种绝缘油对绝缘纸热老化速率的影响,证实了混合油对油纸绝缘老化速率起到明显的抑制作用。为了进一步分析混合油对纤维素热老化的抑制机理,本文采用X射线光电子能谱（XPS）法,对在两种绝缘油中老化的绝缘纸表面及内部的XPS碳谱（碳原子的化学态）进行了研究,并结合表征绝缘纸老化程度的传统特征量-聚合度和油中糠醛含量进行了分析。结果表明,与矿物油相比,在混合油中老化的绝缘纸产生了新的基团-酯基（O-C=O）,这是混合油抑制绝缘纸热老化的主要原因。通过XPS碳谱的定量分析,发现形成酯基的碳原子主要位于纤维素链中的葡萄糖环上,为今后绝缘油和绝缘纸的抗老化改性提供了参考。%This paper studied how insulating oils,namely mixed insulating oil of mineral oil natural ester and 25# mineral oil,influence thermal aging rate of insulating paper and verified that the mixed insulating oil can effectively inhibit the thermal aging rate of insulating paper.For an in-depth investigation of the inhabitation mechanism,the X-ray Photoelectron Spectroscopy（XPS） was employed to obtain the XPS carbon spectra from both the surface and the inside of insulating papers immersed and aged in aforementioned insulating oils respectively,furthermore,combined with traditional parameters indicating aging extent of insulating paper： degree of polymerization（DP） and furfural content in oil,the spectra were thoroughly studied and analyzed.The obtained results reveal： a new group-ester group（O-C=O） is generated in the insulating paper aged in mixed oil,which is believed as the prime reason why the mixed oil inhibits the thermal aging rate of insulating paper;The quantitative analyses of XPS carbon spectra indicate the carbon atom of the newly generated ester group mainly oriented in the glucose ring of the cellulose chain,which provides valuable information for anti-aging modification of insulating oil and insulating paper in future.