BTCA改性对纤维素绝缘纸介电性能的影响

Effect of BTCA Modification on Dielectric Properties of Cellulose Insulating Paper

研究了1,2,3,4-丁烷四羧酸(BTCA)改性对纤维素绝缘纸介电性能的改善效果,利用傅里叶变换红外光谱分析及分子动力学模拟对改性前后纤维素的官能团变化和分子链运动进行表征和计算,并对制备的改性纤维素绝缘纸的介电性能、交流击穿强度、机械性能等进行了分析。结果表明,经BTCA改性后纤维素链间通过酯基交联,极性羟基减少,分子链运动(柔性)减弱,分子极性强度明显降低;当BTCA浸渍浓度为0.2 mol/L时,改性纤维素绝缘纸在工频下的介电常数和介质损耗比未改性时分别降低了12.0%和21.7%,交流击穿强度和抗张强度分别提高了9.7%和12.0%,断裂伸长率变化不明显,BTCA改性纤维素绝缘纸既保持了良好的机械性能和交流击穿强度,介电性能也得到了最大提升。

The effect of 1,2,3,4-butanetracarboxylic acid(BTCA)modification on the dielectric properties of cellulose insulating paper was studied. The changes in functional groups and molecular chain motion of cellulose before and after modification were characterized and calculated by Fourier transform infrared spectroscopy and molecular dynamics simulation. The dielectric properties,AC breakdown strength,and mechanical properties of the prepared modified cellulose insulating paper were analyzed. The results showed that after BTCA modification,the cellulose chains were cross-linked by ester groups,the polar hydroxyl group decreased,the molecular chain motion(flexibility)weakened,and the molecular polar strength reduced significantly. When the BTCA concentration was 0. 2 mol/L,the dielectric constant and dielectric loss of the modified cellulose insulating paper at power frequency were reduced by 12. 0% and 21. 7%,respectively compared with the unmodified counterpart,and the AC breakdown strength and tensile strength were increased by 9. 7% and12. 0%,respectively. The change in elongation at break was negligible. The modified cellulose insulating paper not only maintained good mechanical properties and AC breakdown strength,but also had the greatest improvement in dielectric properties.