Electrospun poly(bisphenol A-co-4-nitrophthalic anhydride-co-1,3-phenylenediamine) fibers: Preparation and potential for use in filtration applications

Poly(bisphenol A-co-4-nitrophthalic anhydride-co-1,3-phenylenediamine) (PEI) fibers were successfully prepared byelectrospinning from PEI solutions in dichloromethane (DCM), 1,2-dichloroethane (DCE), N-methylpyrrolidone (NMP) andcertain mixtures between NMP and N,N-dimethylformamide (DMF). Electrospinnability of PEI solutions in NMP was greaterthan that in DCM and DCE. The addition of DMF with NMP for the preparation of PEI solutions helped improve electrospinnabilityof the PEI solutions. The effect of solution concentration on morphological appearance and/or size of the obtainedproducts was investigated. At low concentrations of the PEI solutions, discrete beads and/or beaded fibers was formed.Smooth fibers were obtained at the highest concentration investigated, i.e., 20% (w/v). The size of the obtained fibers wasfound to be an increasing function with the solution concentration or, to be exact, the solution viscosity. The water fluxesthrough the electrospun fiber mats prepared from 20% (w/v) PEI solutions in 75/25 and 50/50 NMP/DMF mixtures wereinvestigated in comparison with the films prepared by phase immersion-precipitation technique. The fiber mats exhibitedmuch greater fluxes of water than the films, which implied their potential for uses as filtration membranes