Study On Wettability Regulation And Particle Separation Performance Of Electrospun Nanofibers

The rapid development of modern industry has caused serious air pollution,especially particulate matter（PM）pollution which has emerged as a globally recognized environmental issue that must be addressed urgently and immediately.The fiber filters have a great application prospect in the elimination of PM pollutants from the air on account of its advantages of diverse material selection,cost-effectiveness,lightweight with high accumulated density,low pres sure porosity,and facile synthesis.The filtering performance of fiber film will degrade in actual applications due to the complexity of the working environment,particularly under extreme conditions such as high PM concentration,high humidity,and high temperature.Therefore,developing filtration materials with high performance,stability,and adaptability to different operating conditions for the removal of PM pollutants are critical.Electro spinning has been well known as a relatively simple and manufacturing method to produce a type of continuous fiber with a nanometer diameter.Based on this,several electrospinning nanofiber materials with super-wettability were prepared in this paper by introducing polymers with low surface energy and spinning template polymers,and their PM removal performances were systematically studied under different PM concentrations,humidities,high temperature,and other harsh conditions.The main contents and results of this paper are as follows:（1）In the first part,a nanofibrou s membrane EPPM with superhydrophobicity and high PM separation efficiency was created by electro spinning two monomers of low surface energy poly dimethyl siloxane（PDMS）and easily electro spinning hydrophobic polymer polymethyl methacrylate（PMMA）.EPPM has an ultra-fine diameter of 3 5 0 nm,a high hydrophobic angle of 161.6°,and a melting point of 325℃.It is an ideal fiber filter with high PM separation performance in harsh environments.Under the condition of high humidity（RH=96±3%）,EPPM can s till achieve close to 100%separation of PM_2.5,and the pressure drop is only 70 Pa,which is only 0.07%of atmospheric pressure.（2）In the second part,by regulating the selection of materials of electrospinning precursor,we could add tough and wear-resistant polymer polyurethane（TPU）,and then blend PDMS and PMMA to prepare superhydrophobic electrospun nanofiber with high mechanical properties,which called P-ETPM.P-ETPM not only has an ultra-fine diameter of about 3 50 nm and a hydrophobic angle of 164°,but polyurethane is a flame-retardant material,P-ETPM has little mass loss at 3 00 ℃,and it is an excellent high-temperature resistant fiber material.Additionally,its mechanical property can reach 3.76 MPa,and the tensile fracture strain can reach over 400%.At the same time,the filtration efficiency of P-ETPM for PM_2.5 can still be greater than 99%,which is an excellent and efficient superhydrophobic electro spun nanofiber for PM separation.（3）In the third part,using polyvinyl alcohol（PVA）as the spinning template polymer,the inorganic silicon particle solution was electro spun into a nanofibrou s membrane with the extremely fine fiber diameter of only 80 nm.As a template,PVA can be removed after being calcined at 800℃ in a muffle furnace,PVA can be removed as a templated.Besides,modified by impregnation of poly viny lidene fluoride-hexafluoropropylene（P VDF-HFP）and 1H,1H,2H,2H-perfluorodecyltriethoxy silane（FAS）to obtain super amp hiphobic electro spun nano-silica fiber film called F-SiO₂ e-NFM.Besides,F-SiO₂ e-NFM has a contact angle greater than 150°for water and low surface energy organic solvents such as kerosene,methylbenzene et al.And almost no deformation or mass loss occurs under high temperature combustion at 1000℃.At the same time,the separation efficiency of PM_2.5 in high humidity environment is almost 100%,which is a kind of superamphiphobic electro spun nanofiber membrane with high-efficiency PM separation and flame retardant potential for practical application.