An investigation of yarn spinning from electrospun nanofibres

Abstract

The aim of the thesis is to investigate yarn spinning from electrospun nanofibres. The concepts of staple and core yarn spinning on electrospun nanofibres has been investigated by examining nanofibre uniformity, alignment, twist insertion and yarn take up by engining and engineering a new take up mechanism. Nylon 6 nanofibres have been fabricated and used throughout this work. The effects of varying the electrospinning parameters such as applied voltage, polymer solution concentration and electrospinning distance on fibre morphology have been established for process optimization. A novel nanofibre aligning mechanism has been devised and systematically revised to enable optimization of alignment process parameters. MWCNTs have been successfully dispersed into nylon 6 nanofibres and have been aligned along the nanofibre body by manipulating the electric and stretching forces with the aid of the alignment mechanism. Novel mechanisms for spinning continuous twisted nanofibre/composite nanofibre yarn and core electrospun yarn have been researched, developed and implemented by making samples. It has been found that defining the velocity and count of the nanofibres entering the spinning zone is important for controlling the yarn count and twist per unit length. By modelling the electrospinning jet, mathematical equations for theoretically calculating the velocity of the jet and nanofibres and their count have been established, necessary for process control. Aspects of practical measurement and comparison of jet and nanofibre velocities have been described and discussed. Tensile testing of single nanofibre and nanofibre mats has been attempted for mechanical characterization. Initial results show the range of tensile strength of nylon 6 nanofibre assemblies and indicate the effect of change of process parameters. A review of those engineering mechanisms related to various nanofibre architectures and their industrial and commercial importance has also been reviewed, described and discussed.