Study On The Process And The Mechanism Of Preparing Polyacrylonitrile-based Carbon Nanofibers Through Electrospinning

Electrospinning with its simple equipment and low cost is considered to be the most effective method to prepare continuous nanofibers.Owing to its large specific area and high porosity,it is popular in tissue engineering,minisensor and filter material,etc.However,its low yield constrains its industrial application,and also is a major concern in the field of electrospinning.In addition,the prepared nanofibers are random nanofiber web,which leads to low mechanical strength and used to be composite with other materials.To broaden its application fields,preparing continuous nanofiber yarn also become a hot research area.Based on this,some new types of methods were obtained for the improvement of output of nanofibers and preparation of nanofiber core-spun yarn,which were used as precursors to prepare micro/nano composite carbon fibers.In the paper,conventional textile yarn can be used as spinneret,from surface of which lots of jets could be ejected through solution immersion,solution entrainment,droplet formation and entering electric field.Jets formation in three different ways can be observed by the high-speed camera.Based on the Maxwell simulation,the effects of fineness,surface structure and materials of spinneret on quality and output of nanofiber were analyzed.Meanwhile,the relationship between parameters(solution concentration,spinning voltage,spinning distance and take-up speed etc.)and quality,output of nanofiber.To solve the problem of low mechanical strength,nanofibers can be covered on the surface of conventional yarn in orientation,which makes core-pun yarn possess nano effects and mechanical strength.This paper proposed a new method that a conventional yarn was placed between two parallel aluminum flakes to twist aligned nanofibers on the surface of core yarn,and then a novel nanofiber core-spun yarn is formed.Micro/nano composite carbon fiber with high crystalline and pre-oxidation nanofiber web with pleasant softness are prepared through water-washing,drying desification,optimal stabilization and carbonization processing.Morphology,changes of structure and property of nanofiber in every heat treatment stage are analyzed by SEM,FT-IR,X-raydiffraction and STA synchronous thermal analyzer.