Nonafiber MembraneofEVOH-Basedlonomer by Electrospinning

Electrospinning isa straightforward and effective technique toproduce nanofiber nonwovens. Inthis paper, acomb ionomerofpoly(ethylene covinyl alcohol) end-capped with sulfonic acid(EVOH-g-SO3H) was synthesized by two-step synthesis process andelectrospun intononwovenmembranes. Theeffect ofprocessing parameters onthefibrous andbeads morphology wasinvestigated byscanning electron microscopy (SEM).Theresult indicated thatthemorphology ofEVOH-g- SO3Hmembranewasheavily dependent ontheelectrospinning process astheelectrospinning voltage (v), theconcentration of polymer solution (c), thesurface tension ofpolymer solution (6), thesolution flow-rate (u), andthedeposition distance between the syringe needle andthecollecting drum(1). A 'beads-on-string' morphology couldbeseenfromSEM imagewhenthesolution waselectrospun inDMAc/water whiledecreasing thesurface tension isa goodwaytowards theformation offibers without beads. Whenthesolution concentration reaches 35wt%,amelded twist-ribbon structure couldappear. Thereisanoptimumrange of solution concentration (5.0-20.Owt%) for a stable electrospinning and nonwovenformation. A higherapplied voltage couldresult ina higher electric chargedensity onthe surface ofpolymer solution jetduring theelectrospinning, they causethehigher splitting tothepolymer jetandresult inhigher density andsmaller diameter ofroundbeads, aswellastheyalso produce thethinner diameters fibers. Keywords-electrospinning; EVOH-g-SO3H; SEM;morphology