Functionalization of polyacrylonitrile nanofibers with beta-cyclodextrin for the capture of formaldehyde

Polyacrylonitrile (PAN) is frequently used in filtering applications due to its sound mechanical properties, chemical resistance and thermal stability. beta-cyclodextrin (beta CD) can entrap molecules and improve the filters' performance. The removal of formaldehyde, a common indoor pollutant, has increasingly attracted widespread attention. In this work, we present two different methods for the production of electrospun PAN nanofibers containing beta CD capable of capturing formaldehyde from the air. The former comprised the addition of beta CD to PAN/dimethyl sulfoxide solutions and the subsequent electrospinning of the mixture. The latter involved the crosslinking of beta CD on electrospun PAN fibers by alkaline hydrolysis and esterification with citric acid. For both methods, we used solutions with different polymer concentration and viscosity. In addition, the rheology of solutions, as well as the morphology, surface area, chemical structure and thermal resistance of electrospun fibers were analyzed. The formaldehyde capture potential of beta CD containing PAN nanofibers was evaluated using high performance liquid chromatography. Conclusively, we found that, while functionalized PAN nanofibers with average fiber diameter from 432 nm to 647 nm might be used for indoor air purification, functionalized fibers obtained by addition of beta CD are more effective for capturing formaldehyde than fibers obtained by crosslinking of beta CD. (C) 2016 Elsevier Ltd. All rights reserved.