| Air quality on a national scale has declined sharply over the past few years,along with the intensification of environmental smearing problems.Issues such as smog and excessive concentrations of suspended particulate matter occur occasionally,which have already severely threatened human beings’physical health.As a result,how to mitigate the detriment brought by air contamination has become an important subject all over the world.Air filter materials have become one of the efficient means of defence due to their effective and fast governance effect.Electrospinning nanofibers have been extensively applied to air filter materials because of their strengths such as fine diameter,uniform bore diameter distribution,preferred bore connectivity,and high specific surface area.Nonetheless,there are some issues in the size of electrospinning nanofibers difficulty in further refinement,compaction accumulation of single-scale nanofiber structure,difficulty in achieving equilibrium between filter efficiency and filtration resistance,and other issues.As a consequence,this article comes up with an approach on the strength of high conductivity and extremely dilute solution to prepare PU microfine nanofibers.Moreover,on this basis,it constructs a multiple spatial-scale PU-PS/FPU nanofiber air filter material with reproducible anti-bacterial functions.The concrete work is as follows:（1）Halide antibacterial agent（GO-GH）is prepared from 5,5-Dimethylhydantoin and Graphene Oxide（GO）,and it is grafted onto the surface of PS/FPU nanofibers by means of surface chemical modification to form PS/FPU/GO-GH nanofiber membrane with reproducible anti-bacterial function.From the laboratory results to see,PS/FPU/GO-GH nanofibers show favourable mechanical capacities（138 MPa）and high-efficiency filtering quality（filter efficiency is 99.85%,and filtration pressure resistance is 79 Pa）.While guaranteeing the filter capacity.The PS/FPU/GO-GH nanofiber membrane had a significant inhibitory effect on colonies and could rapidly sterilize bacteria within 5 min.The inhibition rate of bacteria was 97.8%for E.coli and 97.2%for S.aureus.At the same time,after several cycles of chlorination,the active chlorine content is more than 92%,and the bacteriostatic rate of E.coli and S.aureus can still reach more than 90%.（2）PS/FPU/GO-GH nanofiber membrane was combined with different gram weight melt-blown cloth to prepare nanofiber melt-blown composite material,and the optimal gram weight was evaluated by synthesizing the results.The results show that the average pore diameter of the composite decreases from 5.43μm to 3.64μm and the porosity increases from67.3%to 83.2%when the gram weight increases from 25 g/m2 to 50 g/m2.The filtration efficiency of PM0.3 reaches 99.97%,and the filtration piezoresistance is only 89 Pa.The quality factor was 0.0911 Pa-1.After electrostatic removal test,the physical filtration efficiency can be maintained above 80%.When the weight of melt-blown Booker is 35 g/m2,it can show good dust absorbing effect（86.5 g/m2）.（3）Ultrafine PU nanofibers were prepared by the theory of high conductivity and extremely dilute solution.On this basis,PU-PS/FPU multi-scale nanofiber air filtration materials were constructed.When the ratio is 1:1,the multi-scale PU nanofibers have the characteristics of small pore size（0.55μm）and high porosity（95.7%）.The filter material demonstrated excellent performance,including high filtration capacity for PM0.3(filtration efficiency of 99.998%,filtration resistance of 92 Pa,quality factor of 0.1298 Pa-1),excellent hydrophobicity（122℃）and high dust capacity（97.3 m/s2）.The filter material successfully demonstrated high air permeability（182 mm/s）.After washing for 10 times and circulating filtration for 10 cycles,the filtration efficiency remained stable and demonstrated a rapid and repeated purification capacity for PM2.5.It can be seen that PU-PS/FPU nanofiber filtration materials can be applied in the fields of air filtration,adsorption,and antibacterial. |
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