| Electrospinning nanofiber membrane shows excellent performance in the field of precision filtration as its small diameter, high surface area and porosity. However, the study of nanofiber structure parameter is still not enough. On the one hand, it would hinder the study of filtration performance of nanofiber; on the other hand, limit the application of nanofiber membrane as filter material. Therefore, it is necessary to study the filtration performance systematically. Polyacrylonitrile and cellulose acetate are the usual membrane filtration material, wettability for PAN was poor, CA is natural biodegradable material and inexpensive, furthermore, it has good wettability. Therefore, both can blend advantages, it can be fit for different filtration domain through the mixing ratio of PAN and CA.In this paper, PAN/CA composite nanofiber membrane was prepared by homemade electrospinning equipment. Infrared spectrometer was employed to research the compatibility of PAN and CA; scanning electron microscope (SEM) and Photoshop software was employed to compare nanofiber morphology and fiber diameter under the different electrospinning parameters; the optimal technological parameter was obtained through single factor and orthogonal experiment; mechanical properties and wettability of PAN and PAN/CA whose mass ratio were 90/10 and 80/20 respectively were tested and compared; porosity of nanofiber was tested by image analysis method and density method respectively; pore distribution of PAN/CA nanofiber and PLA spunbonded nonwoven ware tested by pore size analyzer; bacterium and air filtration performance of composite nanofiber membrane ware tested by bacterium filter and integrated filter analyzer, and discussed the filtration mechanism, results showed as bellow:(1) The breaking strength and breaking tenacity of nanofiber membrane whose mass ratio was 90/10 had enhanced by 37.7% and 4.42%, comparing with PAN nanofiber membrane;(2) The compatibility of PAN and CA is low in some of the amorphous region;(3) Nanofiber diameter of PAN/CA increased with the solution mass fraction increased, increased with the electrospinning speed increased, decreased with voltage increased, decreased with receiving distance increased. Nanofiber whose diameter was 100~130nm and average pore size was 1.26nm could be available in these conditions: solution mass fraction was 11%, voltage was 18kV, receiving distance was 15cm, and the electrospinning speed was 0.6ml/h.(4) Image analysis method is simple and easy to carrying out and straightforward, the error was 4.07% compare with density method, which can substitute for image analysis method.(5) The introduction of CA could improve wettability of PAN. Nanofiber membrane has excellent filtering properties and filtration efficiency reached 98% up, which has high quality filtration performance.(6) Electrostatic effect, interception and diffusion played an important role in filtration for nanofiber membrane. The filter efficiency for the particles diameter about 5.0μm reaches 99.65 % after nanofiber membrane loaded on nonwoven substrate for 5 min; the filter efficiency for the particles diameter about 2.0μm reaches 99.98 % after nanofiber membrane loaded on nonwoven substrate for 10 min, which could satisfy high effective filter requirements, and nanofiber membrane presents excellent performance in the field of precision filtration. Look forward to get high efficiency filtration material by the means of mutil-nozzle in order to realize industrialization. |
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