纳米纤维素掺杂改善油浸纸介电性能的研究

Study on Improving the Dielectric Properties of Oil-immersed Paper by Doping Nano-cellulose

以探究阳离子纳米原纤化纤维素(CNFC)掺杂提升油纸绝缘介电性能为目的,制备了质量分数为0%、3%、5%和10%的纳米纤维素复合绝缘纸,用绝缘油真空浸渍后,在130℃下进行为期20d的加速热老化试验,研究了绝缘纸的化学结构、聚合度、抗张强度、相对结晶度、体电阻率、介电常数、介质损耗、击穿强度、纸中水分含量等参数随老化时间的变化规律。结果表明:CNFC掺杂对绝缘纸的化学结构影响很小;与普通绝缘纸相比,热老化过程中改性纸分子量和抗张强度下降速率减缓,水分生成量减少,体电阻率与击穿性能提升,但介电常数与介电损耗有少许增加。该文认为CNFC通过增加阳离子基团,增强了纤维素的链间作用力;通过填充绝缘纸内部气隙,提升了绝缘纸的击穿性能;通过增加氢键含量,延缓了纤维素链的裂解,提升了绝缘纸抗热老化性能。

In order to explore doping cationic nanofibrillated cellulose(CNFC)to improve the insulating dielectric properties of oil-paper,insulating papers with concentrations of 0%,3%,5%and 10%were prepared.After vacuum impregnation with insulating oil,the insulating papers were thermally aged at 130℃for 20 d.Furthermore,the chemical structure,average molecular weight,tensile strength,relative crystallinity,volume resistivity,dielectric constant,dielectric loss,breakdown strength,and moisture content of the insulating paper with aging time were studied.The results show that,CNFC has a negligible effect on chemical functional groups and crystallinity.Compared with ordinary insulating papers,during the thermal aging process,the molecular weight and tensile strength of modified paper decreases at a slower rate,the amount of water generated is reduced,the volume resistivity and electrical breakdown performance are improved,but the dielectric constant and dielectric loss are slightly increased.It is believed that CNFC strengthens the adhesion between cellulose chains by adding cationic groups,the breakdown performance of the insulating paper is improved by filling the internal air gap of the insulating paper,the cleavage of the cellulose chain is delayed by adding the hydrogen bond,and the thermal aging resistance of the insulating paper is improved.