Study On Effect Of Lithium Chloride On Cellulose Acetate, Polyvinyl Alcohol Polymer Solution And Microspheres By Electrospinning

This paper is to study the effect fiber morphology by electrospinning by using Polyvinyl Alcohol (PVA) and Cellulose Acetate (CA), adding LiCl with different concentration. The morphology and the fineness of the nanofibers mat were observed through scanning electron microscopy (SEM), and the jet was intercepted by glass slide to evaluate the changing rate of the diameter of fiber on spinning. Then, because of the hydrophobicity of CA, we used CA/Acetone solution to drop in PVA aqueous solution to produce microspheres fiber and analyzed how to make ideal solution.This paper is divided into two parts. The first part is chapter two and three, mainly focus on the effect of nanofiber diameter, distribution, and the jet morphology which is in the process of spinning and internal structures after adding different concentration of inorganic salts in polymer solution. The second part is to study the manufacture of microspheres fiber.The first part of the study showed that if LiCl was added to PVA, spinning process become easy. Under the same PVA concentration, when the concentration of LiCI increased, the diameter of spun fibers increased, the length of stability part of fiber decreased, the diameter of liber decreased, and the diameter of instability part reduced. If adding LiCl into CA, spinning process became difficult. LiCl made CA having salt effect, and improved spinning speed of the solution, so that the spinning liquid solidified ahead of time, unable to obtain fiber mat. Since we cannot intercept the fiber if LiCl was added to CA, then CA without LiCl was used to study the changing rate of the diameter of the fiber. Through the experimental, we verified the theoretical derivation and obtained the index relation between the jet radius of electrospinning nanofiber and axial distance. It showed that the changing rate of the stability part is r～z-1/2 along the axis of the fiber diameter and the changing rate of the instability part is r～z-1 along the axis of the fiber diameter.In the second part of the study showed that, with the solute of the 2.5mg/ml CA/Acetone solution, the ideal spinning solution is 5%PVA+0.2%LiCl. It can make the shape of microspheres better. Preparation of microspheres fiber needs to use two kinds of incompatible substances, with low concentration and low polymerization degree of the polymer as the solvent, to obtain the microspheres fiber with good shape.