The Research On Preparation And Properties Of Pani Electret Composites Applying In Air Filtration

In recent years,with the rapid development of industrialization,air quality problems have become increasingly serious,causing major damage to human health.Therefore,the use of air purification products has become an important measure for people to prevent diseases.With the increasingly prominent environmental problems and the urgent needs of the people,air filter materials have developed rapidly.Electret air filter material is a new type of filter material.Based on its physical interception,inertia effect,Brownian diffusion,gravity deposition and other effects of the filter material,the material is electretized to charge it,which can charge the air dust to play a role of electrostatic adsorption,so that improving the filtering performance of the material.It is a research hotspot to enable filter materials to carry a uniform and stable charge.Intrinsic polyaniline is an insulator with high volume resistivity,good dielectric properties,and good energy storage characteristics.At present,the processing technologies for preparing air filter materials on the market are mainly needle punching and meltblown processes.Needle punched nonwovens are widely used in factories for exhaust emission treatment due to their large dust holding capacity,but the filtration accuracy is low;meltblown non-woven fabrics are widely used in masks,air purifiers and other fields due to their small pore size and high filtration accuracy,but they have low dust holding capacity and short service life.Therefore,this topic based on the characteristics of acupuncture filter material with large dust holding capacity and long service life,etc.,combined the acupuncture filter material with intrinsic polyaniline for electret treatment to improve the filtration performance of the acupuncture filter material in order to broaden the application of polyaniline field.The main research contents of this topic are as follows:(1)A polypropylene needle-punched filter material with a basis weight of 100 g/m~2 was prepared by the needle-punched reinforcement process.A polyaniline/polypropylene composite air filter material was prepared by in-situ polymerization,and a single-factor experimental analysis was performed on the polymerization conditions of the in-situ polymerization of polyaniline,and the optimal polymerization conditions were obtained through various basic performance tests as the concentration of hydrochloric acid.When the concentration was 0.8 mol/L,the concentration of aniline monomer was 0.8 mol/L,and the concentration of ammonium persulfate was 1 mol/L,the adhesion amount of polyaniline reached the maximum,and the volume resistivity was the largest.(2)The corona electrets of polypropylene needle-punched filter materials and polyaniline/polypropylene composites were self-constructed using a corona electret device.The effects of different electret conditions on the materials were investigated through single-factor experiments.The performance changes of the two materials were compared and analyzed.Finally,the optimal electret conditions are obtained by orthogonal design.Under these conditions,the charge decay and charge distribution of the material are observed and analyzed.The results show that the surface electrostatic potential of the material is closely related to the electret conditions.By compounding polyaniline with polypropylene needle-punched filter materials,the surface electrostatic potential of corona electret is increased about 60%and the filtration efficiency is.improved about 20%,the charge retention rate in 300h is about 60%compared to a single polypropylene material.(3)The material was subjected to friction electret treatment with a fabric flat mill.The influence of friction electret conditions on the material was investigated through single-factor experiments,and the performance changes of the two materials were compared.Finally,the method of orthogonal test design was used to obtain the optimal friction electret conditions.Under this condition,the charge attenuation and charge distribution of the material were observed and analyzed.The results show that the significant influence of the experimental influencing factors is ranked as friction pressure>friction times>friction speed.Through the compounding of polyaniline and polypropylene needle-punched filter materials,the surface electrostatic potential is increased by 25%,and the filtration efficiency is increased by about12%,and the charge retention rate is about 50%within 30 minutes.(4)Based on the influence of corona electret and friction electret on material properties,a comparative analysis is performed.Comparing the two electret processes,the corona electret can make the surface of the material have a higher surface electrostatic potential,but the charge distribution of the friction electret is more uniform,and the filtration performance of the two electret processes improves the material.However,the friction electret is likely to cause the material to wear out due to excessive friction,resulting in accelerated charge dissipation and poor filter performance.