Fabrication Of Anion And Cation Exchange Membranes By Electrospinning And Investigation Of Their Properties

Today, as an essential separation material, both anion and cation exchange membranes have been used not only in industries but also our daily life. Electrospinning is a kind of simple and efficient technology to prepare ultrafine fibers. It can fabricate microns to nanoscale fibers continuously. Therefore, this article adopts the method of electrospinning to prepare anion and cation exchange membranes. On the one hand, the anion and cation exchange membranes prepared by electrospinning are made up of a lot of ultrafine nanofibers. And nanofiber has a larger specific surface area, thus it increases the contact area between exchange membranes and solution to improve the ion exchange efficiency. On the other hand, compared with the traditional methods to prepare ion exchange membranes, ion exchange membranes prepared by electrospinning have not used toxic substances, with low energy consumption, friendly to the environment, and accord with the direction of sustainable development. This paper focuses on the synthesis and characterization of copolymer, membrane preparation and property research, and made the following progress:First of all, choosing two kinds of anion and cation exchange monomers, we selected N, N-dimethylaminoethyl methacrylate (DMAEMA) as anion exchange monomer and styrene sulfonate (SSS) as cation exchange monomer. A unit was needed to have crosslinking effect, so we choosed 2-hydroxyethyl methacrylate (HEMA) as crosslinking unit. Through exploring conditions, we used solution polymerization method to prepare Poly (DMAEMA-co-HEMA) and Poly (SSS-co-HEMA) copolymer.1H NMR, FTIR were adopted to analyze and determine the products.Secondly, after having found the reasonable solvents, the copolymer solution was electrospun by the home-made electrospinning device. Then, we designed the orthogonal experiment and explored the influence factors of solution concentration, voltage, flow rate, tip to collector distance on fiber diameter. Ultimately, the experimental data was analyzed and got the optimal electrospinning condition that can make the fiber diameter smaller and more uniform. The anion and cation exchange membranes were electrospun respectively under the optimal conditions. The water uptake, mechanical properties, thermostability and permselectivity of the membranes were measured after crosslinking. Finally, under the conditions had explored above, the anion-cation exchange membranes which can exchange not only anion but also cation were prepared by conjugate electrospinning.