Influence Of Environmental Factors In The Charge Storage Stability And The Performance Of Melt-blown Polypropylene Nonwoven Fabric

In current years fine particulate matter strained consideration because of its detrimental threat to general health,environment,and ecology.So that it's an obvious matter to bring some system to purify it from our atmosphere.For this issue,air filter is a great solution to purify it.In this matter,electret air filters open a new era.As we know,most of the electret air filters nowadays made of melt-blown polypropylene nonwoven fabric.It's well known that the electret charge storage has a positive correlation with electret filters.However,in many cases,the charge storage performance of electret filters would be influenced by the surrounding environment,such as chemicals,solvents,oil mist,temperature,and humidity.Fibrous air filters are broadly utilized for dust assortment and ecological conservation.Successful filtration of dust particles is vital because such particles comprise a wellbeing danger.Electret polypropylene filters are regularly utilized for the filtration of submicron haze particles from dirtied gases.Fibrous materials utilized for air filtration give high filtration proficiency low air opposition because of low-pressure drop over the filter and show high productivity of gathering dust particles.In our current work,the electret charge storage of polypropylene melt-blown nonwoven fabrics with different crystallinity was evaluated under different temperature(25?.50?.75?,100?)and humidity(60%,80%.and 95%)at different time interval by SIMCO FMX-004 electrostatic field meter.Specifically,we analyzed the sample structure through different experiments such as SEM.XRD,pore size distribution,the fiber diameter estimated using Image J and the mean of 100 fiber diameters were determined.The samples were kept in a constant oven by controlling the temperature of 25?,50?,75? and 100? consecutively in the periods of 1-20 days(while the relative humidity was being 60%).and then the charge amount of samples was tested by Simco-ion Digital electrostatic field meter.Similarly,the samples were stored in a humidity chamber at a relative humidity of 60%,80%,95%in the periods of 1-20 days,while the temperature was being at 25?,and then the charge amount of samples was tested by Simco-ion Digital electrostatic field meter.Besides,the effect of temperature on the structure and filtration properties of melt-blown nonwovens were investigated.Fiber diameter,pore size,thickness,areal weight,porosity,crystallinity,filtration efficiency,and pressure drop were evaluated.And also the relastionship between structure parameters and performance of nonwovens in pressure drop and filtration efficiency was analyzed.Based on the experimental results,we found that in most of cases the increase of temperature led to the increase of surface charge intensity of nonwovens,however,there is no significant differences.The higher crystallinity of samples had high surface charge intensity.The increase of humidity led to a significant decrease of surface charge intensity.However,all the results had large standard deviation due to the irregular surface structure of nonwovens.The temperature had slight impact on nonwoven structure,however it has big influence in performance of nonwovens.The mean pore size and porosity played significant roles in pressure drop and filtration efficiency of nonwoven,the higher porosity led to a lower pressure drop and a higher filtrartion efficiency.In addition,the pressure drop and filtration efficiency had positivie correlation.And the results could provide some guidances for development of industrial products.The environmental factors are still very important aspects for evalution the performance of nonwoven filter in their lifetime service and their efficiency under certain conditions,for instance,in oily conditions and in different chemical conditions.Therefore,there are still much work needed for improving the performance of nonwoven in air filtration.