The Synthesis And Investigation Of Novel Electrospinning Processing Additives

Electrospinning has been recognized as an efficient technique for the fabrication of polymer nanofibers. Some issues in this field are usually getting fibers with beads at lower concentrations and fiber entangling at higher concentrations. Hyperbranch polyester end groups were modified with alkyl and fluoro-alkyl compounds of different chain lengths to produce alkyl-modified and fluoride-modified H20 derivatives. This work explored the use of these new compounds as additives for PAN solutions for a better electrospinning. The above mentioned issues were relsolved efficiently by those alkyl-modified and fluoride-modified hyperbranch polyesters. The electrospun fibers from 17wt% PAN/DMF solutions containing 1wt% (with aspect to PAN) H20-g-PFOA were uniform and seperated, while the diameter of fiber was significantly reduced.The work tried to analyze the relationship between the morphology of fibers and rheology properties of electrospinning solutions.The change of apparent viscosity with shear rate, shear stress with shear rate, nonNewtonian index, the longest relaxtion, and configuration viscosity index were investigated. Rheological measurements revealed that addition of those new compounds in small amounts to 17wt% PAN/DMF solutions leads to reduction of entanglement density, by which better fibers were formed. It was found that the derivatives of H20, especially the H20-g-PFOA cound efficiently improve the morphology of fibers electrospun at high concentrations.