Preparation And Performance Study Of Nanofiber Air Filter Material With Health Monitoring Function

With the rapid development of industrialization and urbanization,the problem of air pollution has become more and more serious,especially particulate matter（PM）pollution in the air,which has seriously endangered people’s lives and health.According to the World Health Organization,air pollution kills around seven million people worldwide every year.In addition,since 2019,COVID-19 has spread in a global epidemic,with various transmission methods and extremely fast transmission,causing great damage to the respiratory system and nervous system of the human body after infection.Coronavirus and other pathogens are easy to adhere to ultrafine particles(PM_0.3),ordinary medical masks and other protective materials can only physically block ultrafine particles,long-term use of ultrafine particles carrying viruses,bacteria and other pathogens will be deposited on the surface of the filter material,increasing the risk of infection.Signs such as respiratory rate and depth of breath are one of the important indicators for monitoring human health,and many diseases（such as heart disease,pneumonia,etc.）can cause changes in the respiratory rate of patients.However,traditional respiratory monitoring methods are extremely inconvenient,patients need to go to hospitals or medical institutions to use large equipment for testing,and portable devices cannot be used for real-time monitoring,increasing the risk of delayed treatment.In view of the above problems,this paper studies and prepares nanofiber membrane air filter materials,and introduces inorganic particles,nano-silver particles,silver-modified carbon nanotubes,etc.,through the structural regulation and functionalization design of nanofiber membrane air filter materials,nanofiber membrane materials with high efficiency air filtration performance with antibacterial,moisture permeable and low-temperature comfort and health monitoring functions are obtained.By optimizing the structure of nanofiber membrane,the functional application of nanofiber membrane is expanded,its killing ability against bacteria and other microorganisms is enhanced,and the comprehensive performance of nanofiber membrane materials is greatly improved.The results of this study can be divided into the following three parts:PVA-co-PE nanofibers were prepared by melt extrusion phase separation method,zinc oxide（Zn O）flower-like nanoparticles were prepared by hydrothermal method,and Zn O flower-like nanoparticles were introduced into the PVA-co-PE nanofiber membrane structure as a"scaffold"to prepare Zn O/PVA-co-PE nanofiber membrane.The appropriate amount of Zn O flower-like nanoparticles can effectively adjust the accumulation mode of nanofibers,optimize the structure of Zn O/PVA-co-PE nanofiber membrane,reduce the pressure drop of nanofiber membrane,and when the weight percentage of Zn O nanoflower particles reaches 50%,the performance of Zn O/PVA-co-PE nanofiber membrane is the best.The PVA-co-PE nanofiber suspension mixed with AgNO₃ solution was sprayed on the PP meltblown non-woven substrate with the electret removed,and the PVA-co-PE@Ag nanofiber composite film（NF@Ag）was prepared by reducing silver ions by UV light irradiation.The results show that the silver nanoparticles on the surface of the nanofibers can improve the hydrophilicity of the NF@Ag nanofiber membrane,and the NF@Ag nanofiber membrane has excellent moisture permeability.NF@Ag nanofiber membrane can achieve a filtration efficiency of 95.80±0.89%and a pressure drop of 122.00±1.73 Pa without relying on electrostatic adsorption.NF@Ag air filter material has excellent antibacterial properties,photothermal disinfection and thermal insulation properties against E.coli and S.aureus.NF@Ag air filter material can be patterned with interdigital electrodes designed as a breath monitoring sensor to accurately detect the respiratory activity and health of the human body.PVA-co-PE nanofiber membrane（NF）was prepared by spraying the PVA-co-PE nanofiber suspension to the PP meltblown non-woven substrate with the electret removed,and then coated with a layer of silver-modified carbon nanotube suspension on the NF surface to prepare Ag@CNTs air filter material.The results show that the introduction of silver-modified carbon nanotubes can significantly improve the hydrophilicity of Ag@CNTs nanofiber membranes,and at the same time impart excellent antibacterial properties to fiber membranes.Ag@CNTs has high-efficiency air filtration performance,with a filtration efficiency of up to96.30±0.41%and a pressure drop of 132.67±3.21 Pa.Ag@CNTs can be used as a moisture sensor,which can test a large relative humidity range（30 RH%-90 RH%）,and can accurately and effectively monitor human respiratory signs.