连续静电驻极纳米纤维基空气滤材开发

Development of Nanofibrous Membrane with Continuous Electret Treatment for Air Filtration

选用聚偏氯乙烯(PVDF)为原料,N,N-二甲基甲酰胺(DMF)为溶剂,二氧化钛(TiO_(2))和氮化硅(Si_(3)N_(4))的混合物为驻极体材料,通过静电纺丝技术制备纳米纤维膜,对其进行静电驻极来进一步提升过滤效率。通过研究所制备的纳米纤维膜的结构、表面形貌以及过滤性能,掺杂了纳米颗粒的PVDF@TiO_(2)/Si_(3)N_(4)纳米纤维膜的过滤性能要强于未掺杂纳米颗粒的PVDF纳米纤维膜,当掺杂的纳米颗粒的浓度达到5%时,所制得的纳米纤维膜的性能最优。在对掺杂纳米颗粒浓度为5%的PVDF@5%TiO_(2)/Si_(3)N_(4)纳米纤维膜驻极过程中,当PVDF@5%TiO_(2)/Si_(3)N_(4)纳米纤维膜驻极后,其纤维的直径和孔径都会有所减小,同时其过滤效率也会进一步增加,达到99.93%,相较于未驻极之前的性能,提升了7.40%。本文还测试了将驻极之后的纳米纤维膜放置后的性能,经过放置后,其电性能会发生不同程度的衰减,但最终依旧会保持一个稳定的电势。为提高放置后的纳米纤维膜的电性能和过滤性能,本文对放置后的纳米纤维膜进行了二次驻极实验,结果表明,驻极之后的纳米纤维膜放置时间越久,其恢复到最佳电势所需要的时间也会越久,但其过滤效率依旧可以达到99%以上,同时所需的时间均在7 min内,实现了充电7 min,即可达到长时间工作的目的。

In this study,poly(vinylidene chloride)(PVDF)was selected as the raw material,N,N-dimethylformamide(DMF)as the solvent,and the mixture of titanium dioxide(TiO_(2))and silicon nitride(Si_(3)N_(4))as the electret material.The nanofibrous membrane was prepared by electrospinning technology,and the electrostatic electret was carried out on it to further improve the filtration efficiency.By studying the structure,surface morphology and filtration performance of the prepared nanofibrous membrane,it was found that the filtration performance of the PVDF@TiO_(2)/Si_(3)N_(4) nanofibrous membrane doped with nanoparticles was better than that of the undoped PVDF nanofibrous membrane,and the nanofibrous membrane prepared with the concentration of doped nanoparticles reaching 5%had the best performance.In the electret process of PVDF@5%TiO2/Si3N4 nanofiber membrane with a concentration of 5% doped nanoparticles,it found that when PVDF@5%TiO_(2)/Si_(3)N_(4) nanofibrous membrane is electret,the diameter and pore size of the fiber will decrease,and the filtration efficiency will further increase to 99.93%.Performance improvement of 7.40% is achieved,compared to that before electret.This paper also tested the performance of the nanofibrous membrane after the electret was placed.After the placement,the electrical performance of the nanofibrous membrane would decay to different degrees,but it would still maintain a stable electric potential.In order to improve the electrical properties and filtration performance of the nanofibrous membrane,a secondary electret experiment on the nanofibrous membrane after placement was conducted.According to the experimental data,the longer the nanofibrous membrane is placed,the longer it takes to recover to the optimal potential.However,its filtration efficiency can still reach more than 99%,and the required time is all within 7 min.The purpose of long working time can be achieved by charging 7 min.