间位芳纶短切纤维/浆粕的配比对芳纶绝缘纸性能的影响

Effect of the Ratios of Aramid Fiber to Pulp on the Properties of Aramid Paper

为了研究间位芳纶短切纤维和浆粕的配比对间位芳纶绝缘纸机械性能和介电性能的影响规律及机理,实验室制备了不同纤维配比的芳纶绝缘纸,测量了芳纶纸的拉伸强度和断裂伸长率,芳纶纸的相对介电常数和介质损耗的频域介电曲线,以及在工频电压下的击穿场强。对比了芳纶绝缘纸和410型Nomex纸的拉伸性能、介电性能以及热稳定性,并结合芳纶纤维的结晶性能及形态分析了纤维配比对芳纶纸拉伸性能和介电性能的影响机理。实验结果表明：随着短切纤维含量的增加,芳纶纸的拉伸强度和断裂伸长率先增大后减小,相对介电常数逐渐减小,介质损耗在低频段（10^-1-10^2 Hz）逐渐增大而在高频段（10^4-10^6 Hz）变化不大,击穿场强随有较大幅度的降低。实验室自制的芳纶绝缘纸的热稳定性已达到Nomex纸的水平,拉伸性能介于Nomex纸横、纵向性能之间。当短切纤维含量较多时,会向芳纶纸中引入较多的微小孔洞,导致芳纶纸的击穿场强有所降低。

In order to study the influence and its mechanism of the ratio of aramid fiber to pulp on the mechanical and dielectric properties of aramid insulation paper, we prepared aramid insulation papers with different fiber ratios in laboratory, and measured their tensile strength, elongation at break, dielectric curves of relative dielectric constant, dielectric loss in frequency domain, breakdown strength under power-frequency voltage. Meanwhile, we compared the lab-made aramid papers with T410 Nomex paper in the aspects of tensile property, dielectric property and thermal stability, and hence discussed the influence of fiber ratio on the aramid papers＇ tensile properties and dielectric properties combined with crystallization and morphology measurement. The results showed that, for the lab-made aramid papers with increasing content of chopped fibers, their tensile strength and elongation at break first increase and then decrease, their relative dielectric constant decreases, their dielectric loss increases slightly at lower frequencies（10^-1-10^2 Hz） but bared changes at higher frequencies（10^4-10^6 Hz）, and their breakdown strength reduces significantly. While having thermal stability close to Nomex paper, the lab-made aramid insulating paper has tensile properties between the horizontal and the vertical tensile properties of Nomex paper. Increasing the content of aramid fibers in aramid paper would introduce more small holes into the paper and hence decrease the paper＇s breakdown strength.