静电纺丝法制备聚醚酰亚胺纤维膜的结构和介电性能研究

STUDY ON STRUCTURE AND DIELECTRIC PROPERTIES OF ELECTROSPUN POLYETHERIMIDE FIBROUS MEMBRANES

采用静电纺丝法制备了聚醚酰亚胺(PEI)纤维膜,通过扫描电子显微镜(SEM)和偏振红外对PEI纤维膜的微观结构进行研究.实验结果显示纺丝液溶剂决定了PEI的可纺性,以N-甲基吡咯烷酮(NMP)为溶剂时,空气湿度显著地影响纺丝过程以及纤维的形态.在相同纺丝工艺条件下,随着纺丝液浓度的增加,所得PEI取向纤维沿辊筒收集方向的排列规整性提高,纤维平均直径由405 nm增加到3.25μm.PEI纤维膜介电性能的研究表明,取向纤维膜的介电常数很小,最低可达到1.1,其介电损耗也维持在较低的水平,纤维膜的接收方式以及热牵伸处理会对PEI纤维膜的介电性能产生影响。

Electrospinning was applied to prepare PEI fibrous membranes.The micro-structure of PEI fibrous membranes was studied by scanning electron microscope（SEM） and polarization infrared spectrum.The experimental results show that under the same solution concentration of PEI,the viscosity of spinning solution in the low boiling point organic solvent is higher than the viscosity in the N-methyl pyrrole（NMP）,the volatility of the solvent and the viscosity of spinning solution have a great effect on the spinnability of PEI.When NMP was used as a solvent,air humidity greatly influenced the process of electrospinning and the morphology of PEI fiber.Under the same electrospinning condition,with raising the concentration of spinning solution,the parallelism of the oriented PEI fibers shows an increasing trend,and the average diameter of PEI fibers is also increasing,ranging from 400 nm to 3.5 μm.The dielectric properties of PEI fibrous membranes were tested by a precision impedance analyzer（4294A,Agilent） in the frequency range of 103 Hz to 107 Hz at the room temperature and under ambient atmosphere.The results indicate that the dielectric constants of PEI oriented fibers are very low,can get to 1.1,meanwhile their dielectric loss are basically unchanged,maintaining at a very low level.The receiving methods of fibers and hot-stretching can influence the dielectric properties of PEI fibrous membranes.