Controllable Preparation Of Intelligent Response Nanofiber Membrane And Its Air Filtration Performance

Global atmospheric changes and air pollution have brought serious threats and challenges to the quality of human life and the safety of other living organisms.It is of great significance to develop efficient protective air filters to remove the most harmful PM_2.5 suspended particles among air pollutants and reduce the public health risks caused by respiratory diseases caused by them.Electrospun nanofiber membranes are widely used in the field of air filtration because of their large surface area,high porosity and good surface adsorption.However,the current fiber air filter has a single protective function,which limits its further application.Therefore,it is of great theoretical significance and application value to intellectualize the electrospun fiber membrane,expand its versatility,controllable preparation of high efficiency and low resistance air filter material,and explore its application in the field of protection.In this work,for the end treatment of air filtration,the intelligent response nanofiber material system was constructed by electrospinning technology.With the optimization of response matrix materials and the design of macro-structure,the air filtration performance of fiber membrane materials and the feasibility of its application as indoor protective window screens and personal protective masks were studied.The research content is mainly divided into the following two parts:（1）In view of the urgency of indoor air protection,we used parallel grids as receiving devices to electrospin polymethyl methacrylate/1,3,3-trimethyl spiro[indo-2,3,3-[3H]naphthol[2,1-b][1,4]oxazine（PMMA/SPO）light-responsive nanofibers deposited on parallel grids.A fiber screen with directional arrangement is obtained.In this work,by regulating the PMMA concentration,the droplets with small diameter formed by turbulent splitting on the surface of the jet first reach the Rayleigh limit and are stretched into fibers under the action of electric field,while the internal jet is not enough to overcome the surface tension and form the microsphere morphology.The effect of the fiber/microsphere morphology on the air filtration performance was further studied.When the concentration of PMMA was 32 wt%,the bead structure of PMMA/SPO composite fiber window screen was beneficial to particle capture,and the filtration performance was excellent.The quality factor of comprehensive evaluation of the filtration performance was 0.0274 Pa^-1.After 100 s of ultraviolet irradiation,the fiber membrane gradually changes from white to purple,and the color difference value reaches 15.56.It has good photosensitivity and can effectively protect against sunlight.In addition,according to the GB T 28592-2012 precipitation grade standard,the mini-type water pump is used to simulate moderate rain.The water transportation efficiency of the screen window is 93.33%,which can realize indoor protection in rainy days.The light transmittance of the screen is no less than 70%during the experiment,which can fully meet the needs of indoor lighting.（2）On the basis of the above work,we further aim at the field of personal protection,by using glutaraldehyde（GA）vapor crosslinking treatment of polyvinyl alcohol/polyvinyl methyl ether（PVA/PVME）nanofiber membrane,and obtain a semi-interactive（semi-IPN）fiber membrane material with light transmission response after wet infiltration.It can realize visual monitoring of the service life of disposable protective masks.Infrared and thermal tests showed that PVA and GA were cross-linked,and PVME chain was bonded to the cross-linked PVA chain to form a semi-interactive structure.In the respiration simulation experiment,the micro-morphology and porosity changes of the semi-IPN fiber membrane showed that the PVME component dissolved in the moisture and filled in the pores between the fibers,which reduced the light refraction of the fiber/air interfaces and the light loss in the membrane.It gave the fiber membrane the light transmission response to moisture.COMSOL software simulated the process of moisture diffusion and verified the gradient light transmittance response of semi-IPN fiber membrane According to the technical specification WS/T 311-2009,the service life of disposable masks is usually no more than 6 hours,and the visualization of the mask use time within 6 hours can be realized by adjusting the film thickness.Moreover,after 6 hours of breathing simulation,the mask still has good filtration performance,and the removal efficiency of PM_1.0 and PM_2.5 is not less than92%.It can meet the air filtration requirements of protective masks.