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

Abstract

Polyacrylonitrile (PAN) is frequently used in filtering applications due to its sound mechanical properties, chemical resistance and thermal stability. β-cyclodextrin (βCD) 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 βCD capable of capturing formaldehyde from the air. The former comprised the addition of βCD to PAN/dimethyl sulfoxide solutions and the subsequent electrospinning of the mixture. The latter involved the crosslinking of βCD 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 βCD containing PAN nanofibers was evaluated using high performance liquid chromatography. Conclusively, we found that, while functionalized PAN nanofibers with average fiber diameter from 432nm to 647nm might be used for indoor air purification, functionalized fibers obtained by addition of βCD are more effective for capturing formaldehyde than fibers obtained by crosslinking of βCD.