Study On Efficient Preparation,Structure Control And Application Of Multi-Needle Electrostatic Spinning Micro-Nano Fiber Composite Yarn

As a major method for preparing nanofibers,research on electrospinning is gaining more and more attention.Nanofibers aggregates prepared by electrospinning have the specificities of high porosity and large specific surface area.Typically,pure nanofiber aggregates have limited their application due to their weak mechanical properties and difficulties in secondary processing.Combining nanofibers with conventional yarns,however,retains the strength of conventional yarns and has the properties of nanofibers,which can be used in the development of new functional textiles with great significance.In this paper,based on the self-developed multi-needle water bath electrospinning device,the electric field simulation software ANSYS Maxwell is used to simulate the electric field distribution of multi-needle electrospinning,to establish a quantitative model for calculating the electric field distribution of multi-needle,and to analyse the effect of electric field variation and electric field interference on the structure of micro-nano fiber composite yarn（MNFCY）under different process parameters.The effects of electric field variation and electric field interference on the structure and performance of MNFCY were analyzed.The results of the study show that the peak field intensity generally occurs at the two sides of the needles under different needle arrangements,while the field intensity at the middle needle is smaller.In the 5#arrangement the electric field is strong and uniform,and a stable jet can be formed.The electric field strength at the needle head increases with increasing voltage and decreasing receiving distance.Secondly,based on electric field simulation analysis,this electrospinning device was used to continuously prepare MNFCY with polyester filament（PET）as the core yarn and polyamide 6（PA6）nanofibers as the cover layer.The effects of needle arrangement,voltage,spinning rate,receiving distance and winding rate on the structure and properties of MNFCY were investigated to optimise the preparation process and to obtain MNFCY with excellent properties.The results show that the diameter of the nanofibers on the surface of MNFCY is the smallest at the receiving distance of 5 cm,under the 5#arrangement,at the voltage of 24k V.The crystallinity of MNFCY increases and then decreases with the increase of the spinning rate.The increase in the winding rate of the yarn can improve the efficiency of preparing MNFCY.Finally,the MNFCY/PANI composite conductive yarn was obtained by continuous conductive treatment based on in-situ polymerization of MNFCY with conductive polyaniline（PANI）attached to its surface,and the effect of reaction solution concentration on its structure and properties was investigated.The conductivity of the MNFCY/PANI composite conductive yarn increased and then decreased as the concentration of the reaction solution increased,with the highest conductivity being 7.53 S/cm.The MNFCY/PANI and PET/PANI composite conductive yarns were made into gas-sensitive elements with the same parameters to study their sensitivity to NH₃.It was shown that MNFCY/PANI showed higher sensitivity to NH₃and shorter response-recovery times,indicating that the nanostructured MNFCY/PANI has better response-recovery to NH₃.In the repeatability test,MNFCY/PANI showed better reversibility,repeatability and stability,and has been initially qualified as an excellent gas-sensitive element.