The Fundamentals of Electrostatic Spinning

Abstract

A mathematical analysis of uncrimping of textile fibers in an electrostatic field is given. One important result of this analysis is that a textile fiber is very little uncrimped in the field strengths that can possibly be used in this process, since higher field strengths cause a dielectric breakdown. A mathematical treatment of the orientation of fibers in an electrostatic field is also given. The amount of orientation depending on the fiber physical properties and process parameters are calculated. It is shown that a freely-suspended single fiber moving in an electrostatic field may perform either a periodic or nonperiodic lateral vibration depending on the magnitude of the electrostatic field strength. It is shown that in an electrostatic spinning process there is little fiber orientation in the time available before the fiber enters into the rotor-electrode. The critical value of the field strength determining whether a fiber will perform a periodic or nonperiodic movement is calculated. It is shown that the transfer of fibers of variable fineness by means of an electrostatic field from the feeding device to the twisting element is a randomizing process of the positions of fibers relative to each other, and this is rather important as far as the yarn evenness is concerned.