Preparation Of Intelligent Thermo-regulating Nanofibers By Electrospinning And Its Performance Study

With the continuous development of society,people have put forward higher and higher requirements for clothing and other textile materials.Its function is also changing from the original role of covering the body and keeping warm to the modern versatility and high comfort.In recent years,the intelligent textile materials which are able to perceive the environment temperature change and regulate temperature by absorb or release heat has caused the attention of many scientific researchers.And the preparation of all kinds of multi-functional thermo-regulated fiber is intensively demanded,thus has great research value.This paper is devoted to the preparation of multifunctional intelligent temperature-regulated nanofiber materials by electrospinning technique.The first part of this paper is the basic experiments part.Firstly,coaxial electrospinning technology is used to prepare the core-sheath structured thermo-regulated nanofibers with different cortical materials and their internal microstructures were adjusted.Octadecane was selected as the core phase change material for its suitable temperature range of phase transition.We synthesized a series of thermal-regulated nanofibers with polyvinyl butyral（PVB）,polyvinylpyrrolidone（PVP）and polyacrylonitrile（PAN）as sheath and octadecane as core.Then the microstructures of the core-sheath nanofibers were adjusted by the selection of core solvents.PVB solution was used as the sheath solution,and the core solutions were isopropyl alcohol,kerosene,chloroform solutions of octadecane and pure melted octadecane.Finally,continuous core-sheath structured and bambo-liked nanofibers with different sizes and spacing of octadecane particles were synthesized.The thermal and mechanical properties of the nanofibers with the above four structures were studied.Finally,it was concluded that the bamboo-like structural nanofibers obtained by using isopropyl alcohol as solving liquid of octadecane had the most comprehensive properties.In the second part,the apparent morphology and thermal properties of intelligent temperature-regulated nanofibers were studied,and the near-infrared absorption function was added to the material.Thermo-regulated fibers with core-sheath structure were prepared by coaxial electrospinning with PVB as sheath and octadecane as core,and the effects of PVB concentration and core feed rate on fiber morphology and latent heat were studied.The results showed that when PVB concentration was 10%and core feed rate was 0.08 m L/h,the fibers had good morphology of cylindrical and the latent heat could reach to 118 J/g.Then cesium tungsten bronze was doped into the PVB sheath,making the composite fibers had the ability to absorb near-infrared light and transferred to heat energy,and it almost had no impact on the spinning process parameters,when the concentration of cesium tungsten bronze was 9%,the latent heat of composite fiber was 96.9J/g.Finally,we synthesized a series of waterproof and breathable（W&B）membranes with thermo-regulated property by coaxial electrospinning with PVDF,PVB and octadecane as the raw material.Firstly,well-performed pure W&B membranes were synthesized by ordinary electrospinning,when the concentration of polymer solution was 19 wt%,and the solvent mass ratio of DMAC and acetone was 5/5,the fibrous membrane had the best W&B performance with water contact angle of 131.4°,hydrostatic pressure of 60.5 k Pa,WVTR of 8.344 kg m^-2d^-1,and tensile strength of 13 Mpa.When octadecane was loaded into the fibers by coaxial electrospinning,although it possessed a thermo-regulated function,other performances all had a certain decrease.In order to improve the performance degradation caused by the load of octadecane,different mass fraction of CNTs were doped into the sheath and studied,the results showed that when the mass fraction of CNTs was 0.75%,the comprehensive performance of the fibrous membranes had an obvious promotion with latent heat of 50.1 J/g,water contact angle of 133.6°,hydrostatic pressure of 59.2 k Pa,WVTR of 7.846 kg m^-2d^-1,and the tensile strength could be as high as 20.2 MPa.