Preparation Of Cellulose-based Degradable Air Filter Material Based On Electrospinning Technology And Its Application In Masks

Air pollution caused by particulate matter seriously threatens people's health,and masks have become the most direct and effective tool for personal protection.At present,the filtration performance of polypropylene(PP)melt-blown nonwovens masks decreases with the attenuation of electric charge,which leads to the decline of protective performance,as well as the poor recyclability of the masks and environmental pollution caused by discarded masks.Therefore,there is an urgent need for the development of environmentally friendly reusable masks.In this paper,cellulose-based degradable air filter materials were prepared by electrospinning technology,and its preparation process,structure and properties were studied systematically,and its application in mask materials was expanded.The specific work is as follows:Firstly,the aim was to prepare a cellulose-based air filter material.Choose cellulose acetate(CA)as spinning raw materials,acetone(Ac)and N,N-dimethylacetamide(DMAc)as solutions to prepare CA spinning membranes.The effects of various parameters(solution concentration,voltage,spinning distance)on the fiber morphology were analyzed,and the filtration performance of CA fiber membrane prepared with different spinning time was tested.The results show that when the mass fraction of CA was 14%,the spinning voltage was 15 k V,and the spinning distance was 18 cm,the uniformity of the prepared fiber was better;But on the whole,the strength of the fiber membrane is low(tensile stress was 0.18MPa),filtration performance was poor(the best filtration performance:filtration efficiency was 89%,pressure drop was 27 Pa,quality factor was 0.082).In order to improve the mechanical properties of fiber membrane,CA/TPU fiber membrane was prepared by introducing thermoplastic polyurethane(TPU)with high strength.The effects of the mixing of CA and TPU spinning solution in different ways(the spinning solution was stirred on the magnetic agitator,the spinning solution was mixed at the coaxial eccentric needle and the spinning solution was mixed at the coaxial eccentric needle)were studied,and the effects on the microstructure,mechanical properties,wettability,pore size and filtration performance of the fiber membrane were studied.The results show that the micro-morphology,mechanical properties(2.48 MPa)and filtration performance of mixed spinning were better than that of concentric spinning and eccentric spinning;when the gram weight was 2.2 g/m~2,the filtration efficiency of fiber membrane prepared by mixed spinning was 99.7%,and the pressure drop was 61 Pa.The conductivity of the CA/TPU spinning solution is low.During the spinning process,the jet is not fully stretched,resulting in large diameter and uneven thickness of the fiber,which in turn affects the performance of the fiber membrane.CA/TPU-x Li Cl ultra-fine fiber was prepared by adding lithium chloride(Li Cl),to the spinning solution,and the effect of Li Cl addition on the properties of the fiber membrane was studied.The CA/TPU-x Li Cl ultrafine fiber was prepared by adding lithium chloride(Li Cl)to spinning solution,and the effect of Li Cl addition on the performance of the fiber membrane was studied.The results show that when the addition of Li Cl was 1%,the prepared CA/TPU-1Li Cl fiber membrane had excellent filtration performance.When the filtration efficiency reached 99.8%,the pressure drop was only 52 Pa;After 10 cycles of testing,the filtration efficiency only dropped by 0.7%;Alcohol disinfection had no significant effect on its filtration performance.In summary,the CA/TPU-1Li Cl nanofiber membrane developed in this study has excellent filtration and durability performance,which can provide new ideas for the production of durable and reusable masks that are urgently needed at this stage,and also provide new solutions to the environmental pollution caused by the extensive use of masks.