Preparation Of Antibacterial Air Filtration Materials For Masks By Electrospinning

Airborne particulate matter(PMs)pollution is a growing problem and a constant health hazard for the population.The recent outbreak of neonic pneumonia has also raised concerns about airborne hazards.Wearing a mask is a simple and easy way to protect against particulate matter and germs.However,there is still room for development of traditional masks.The meltblown nonwoven fabric used in the filter layer of traditional masks needs to be electreted to achieve high filtration efficiency,and the filtration efficiency of the filter material will decrease with the loss of charge after electreting;it is also important that the air filter material for masks has antimicrobial properties,and the masks are easy to become a source of germ infection and transmission after use,but there is a lack of attention to the antimicrobial properties of masks.Therefore,the development of an efficient antimicrobial mask filter material has become a hot topic in academia and industry nowadays.Nanofiber membranes prepared by electrospinning technology have the advantages of high specific surface area,controlled morphology and multifunctional fiber surface,which provide a feasible method to prepare highly efficient and low resistance functional filter materials with unique advantages as high efficiency air filtration materials and have received wide attention from scholars in the field of filtration.Focusing on the filtration materials for protective masks,and pollutants such as particulate matter and germs present in the air,this topic selects green and environmentally friendly materials,and designs and prepares several antimicrobial fiber membranes with electrospinning as the main means,and applies them in air filtration.The main research contents and conclusions of the thesis are as follows:(1)A multifunctional CS/polyvinyl alcohol(CS/PVA)electrospun nanofiber membrane with high filtration efficiency and low filtration resistance was prepared using the natural antimicrobial properties of chitosan(CS),and the filtration efficiency of CS containing different time alkali treatments was investigated.The results showed that the CS/PVA fiber membrane with high filtration efficiency(99.9%)and low filtration resistance(77 Pa)was obtained at 12 h of CS alkali treatment time,and the fiber membrane also had some antibacterial properties.Finally,the designed CS/PVA fiber membrane was applied to oil-water separation,and the results showed that the separation performance of the fiber membrane was greater than 98%for edible oil,paraffin oil and n-heptane,and greater than 90%for lubricating oil in the oil-water system.The cycling performance of CS/PVA on oil-water separation was also tested,and the separation efficiency of more than 96%was maintained after 5 cycles for edible oil,for example.(2)In order to obtain better antimicrobial performance as well as reusability,1,3-dichloro5,5-dimethylhydantoin(DCDMH)was therefore selected as the antimicrobial agent with poly lactic acid(PLA)as the recyclable filter layer after raw material spinning.Excellent filtration performance and reusability.The effects of different contents of DCDMH(lwt%,2wt%,3wt%)on the filtration performance and antimicrobial performance of the fiber membrane were investigated.The results showed that with the increase of DCDMH content,the filtration resistance of the fiber membrane gradually increased with the increase of DCDMH content at the same spinning time.The optimal filtration performance,filtration efficiency(99.9%)and pressure drop(114.5 Pa)were obtained for the fiber membrane with 1 wt%DCDMH content at a spinning time of 50 min.The stability of the active chlorine content in PLA/DCDMH fiber membranes was tested,and the three DCDMH content fiber membranes were able to maintain the active chlorine content at more than 95%of the original content after one month of sitting,which has good stability.In addition,the membrane was soaked in sodium hypochlorite solution and sodium thiosulfate solution several times to simulate the process of disinfection and replenishment of active chlorine,and it was found that the filtration efficiency of the membrane remained above 95%after three cycles,but the pressure drop gradually increased.(3)The fiber membranes with multi-stage fiber diameter structure were prepared by adding different contents of organic salt tetrabutylammonium chloride(TBAC)to the PLA/DCDMH spinning solution.The effect of TBAC content on fiber diameter and filtration performance was investigated,and when the TBAC content was 1 wt%and the spinning time was 30 min,the filtration efficiency of the fiber membrane was optimal with 99.9%filtration performance and 176 Pa filtration resistance.The comparative experiments showed that the multi-stage fiber diameter membranes have better filtration performance than the single fiber diameter membranes.In addition,the membranes exhibited good stability of active chlorine content and antibacterial properties.