Preparation And Properties Of Aramid Nanofiber Insulating Paper

Aramid nanofibers(ANFs)not only have the advantages of high strength,high temperature resistance and electrical insulation of aramid fibers but also have the characteristics of large aspect ratio,high specific surface area and strong surface activity.These characteristics contribute to the close combination of fibers to form a dense fiber network structure,which is an ideal material for the development of nanofiber insulation paper.In this paper,two kinds of aramid nanofiber paper with good insulation were prepared by different processes.The main contents are as follows:(1)Meta aramid nanofibers with uniform diameter distribution,softness and low crystallinity were prepared by solution spraying method.After mixing with para aramid nanofibers obtained by mechanical treatment,high density aramid nanofiber insulation paper was obtained by wet forming and high temperature and high-pressure hot-pressing process.The effects of two kinds of fiber ratio and hot-pressing treatment on the insulation paper have systematically studied and the influence of the insulation paper on the electrical insulation performance of the insulation paper.The results show that the insulation paper with a 5:5 aramid nanofiber ratio has the best mechanical properties and electrical insulation.After hot pressing at 245?,30 MPa and 5min can reach 37 k V/mm and1.34×10¹⁵?·cm,respectively.(2)Aramid nanofibers(ANFs)were prepared by stripping para aramid chopped fibers in KOH/DMSO system.The modified BNNs/ANFs system was prepared by mixing 3-aminopropyl trihydroxy silane surface modified BNNs with aramid nanofibers.The modified BNNs/ANFs nanofiber insulation paper with high insulation,thermal conductivity and mechanical properties was prepared by vacuum filtration,vacuum drying and high temperature hot pressing.The surface modification of BNNs was confirmed by FTIR,TG and XPS.In addition,the basic morphology,structure,mechanical properties,thermal conductivity and electrical insulation of the modified BNNs/ANFs nanofiber insulation paper were characterized.The results show that when the loading amount of modified BNNs is 10 wt%,the nanocomposite paper has excellent mechanical properties and insulation properties,and its breaking strength,dielectric strength and volume resistance can reach 238 MPa,156 kV/mm and 6.95×10¹⁶?·cm,respectively.