Modified polyurethane nanofibers as antibacterial filters for air and water purification

Abstract

In the present research, we aimed to produce polymer nanofibrous filters for antibacterial purification of air and water and prove their efficiency and stability under simulated filtration conditions. Polyurethane solutions were modified by microparticles (700 nm to 1 μm) and nanoparticles (≈50 nm) of copper oxide (CuO) in order to compare the influence of the dimensional characteristics of modifier on the properties of composite filters. Antimicrobial additives (used concentrations 5; 7; 9.5 and 12%) were introduced directly into the pre-electrospinning solutions and then were thoroughly intermingled. The rheological behaviour of such solutions was studied before the electrospinning process. Then composite layers were prepared by the industrial Nanospider technique. SED-EDX results confirmed a smooth and well-oriented structure and the presence of CuO for all of the modified samples. The antibacterial efficiency of the nanofibrous mats with micro- and nanoparticles was studied using the model microorganisms Escherichia coli and Staphylococcus gallinarum. The stability of particle fixation into the fiber structure was determined under the simulated conditions of water filtration. Moreover, a special device AMFIT-13 was designed and used to characterize the bacterial filtration efficiency of nanofibers for air purification. A very important result of this research is a proven fact that microparticles of CuO are a more suitable additive for the selected method of antibacterial modification of polyurethane filters than nanoparticles from technological and economic points of view.