Study On Forming Mechanism And Properties Of Electro-spinning Composite Nanofiber Filter Material

With the rapid development of industrialization and urbanization in China,air pollution caused by PM2.5 has become a serious threat to people’s health and life.Under the current high emission standards,traditional fiber filtration materials can not meet the higher filtration requirements due to the problems of coarse fiber diameter,uneven fiber distribution and large pore diameter.Electrospinning technology can produce nanoscale spinning fibers,and the capture effect of PM2.5 is remarkable.At present,electrospinning research in the field of air filtration is mostly small experiments,traditional electrospinning device has small output,easy to plug needles and difficult to clean and other problems,electrospinning nano fiber filter material still has low strength and high filter resistance problems.In this paper,a linear electrode type batch electrospinning device was designed,and based on the device,the electrospinning process parameters and comprehensive performance of the composite filter material were studied.Finally,a kind of electro-spinning air filter material with high filtration efficiency,low filtration resistance and good mechanical strength was developed.In this paper,a linear electrode type batch electrospinning device was designed,and based on the device,the electrospinning process parameters and comprehensive performance of the composite filter material were studied.Finally,a kind of electro-spinning air filter material with high filtration efficiency,low filtration resistance and good mechanical strength was developed.(1)A linear electrode type batch electrospinning device was designed.The device was mainly composed of a linear electrode type spinning module,a flat plate type lifting and receiving module,a rewinding and unwinding module,a precision liquid supply module and a high-voltage power supply module,which consisted of a liquid storage module and a lifting platform.Lifting liquid storage module can quickly brush the spinning electrode,which provides a guarantee for the efficient and large-scale preparation of nanofibers.The plate-type lifting and receiving module makes the spinning collection distance easy to adjust.Then complete the selection of precision liquid supply module and high-voltage power supply module,followed by the completion of the overall layout and design of the device,the device for safety protection treatment,and finally complete the physical design and construction of the device,to solve the traditional electrospinning device output is small and easy to block the needle and other problems.(2)Based on COMSOL software,a simplified electric field model of the spinning working chamber was established.The distribution characteristics of the electric field in the working chamber were analyzed.The influence of the electrode diameter,the spinning voltage and the collection distance on the working field strength was explored,and the size of the spinning electrode was optimized.(3)TPU/PAN composite nanofiber filter material was prepared based on a self-designed linear electrode batch electrospinning device.The effects of different mixing ratio of spinning solution,spinning voltage and collection distance on the fiber surface morphology and coating fastness of TPU/PAN composite nanofiber filter membrane were investigated.Finally,the optimum spinning parameters were determined as follows: TPU/PAN mixing ratio 3:1,spinning voltage 45 k V,collecting distance 19 cm.(4)The comprehensive performance of TPU/PAN composite nanofiber filter material was analyzed based on the optimal process parameters.Firstly,the absorption bands of TPU/PAN composite nanofiber filter material were analyzed,and the existence of TPU and PAN components was proved.Then,the filter effect and filter resistance of the composite filter material were detected,and it was found that the composite filter membrane became thicker,which contributed to the improvement of the filter effect,and also caused the growth of the filter resistance.The composite filter membrane thickness is too large or too small can not meet the use of air filtration requirements,through the calculation of quality factor to find the best filtration performance of composite nanofiber filter material.Then,the pore size and porosity of the composite filter material are analyzed.It is found that the thickness of the composite filter membrane is negatively correlated with the pore size and positively correlated with the porosity.When the composite membrane is gradually thickened,the increase rate of porosity will slow down.Secondly,the air permeability of the composite filter material is analyzed,and it is found that the composite filter membrane becomes thicker,and the air permeability of the filter material will decrease.Finally,thermogravimetric analysis was conducted on the composite filter membrane,and it was confirmed that the TPU/PAN composite nanofiber filter material had good thermal stability in the temperature below 280℃.