Optimal Design Of Nonwoven Air Filtration Materials: Effects Of Fiber Morphology

Compared with the traditional round fiber,profiled fiber has larger specific surface area,increases the porosity,particle loading capacity and collection efficiency of the filter material,and also has the indispensable excellent performance in the field of filtration,such as:pollution resistance,fluffy air permeability,adsorption and so on.In order to make the air filter material with high efficiency and low resistance filtration performance and excellent mechanical properties,meet the theme of green environmental protection.In this project,cotton,viscose,acetic acid,lyocell and polyester fibers were used as raw materials to prepare nonwoven filter materials by carding,netting and Spunlaced processing methods,and the influence of fiber morphology on the performance of nonwoven filter materials was discussed.Firstly,the properties of cotton,viscose,acetic acid,lyocell and polyester were studied.The results show that the degree of profile,shape coefficient and specific surface area of acetate fiber are the largest,which are 0.701,31.409 and 4878 cm~2/g,respectively;the mechanical properties of polyester fiber are excellent,and the breaking strength is 4.53 cn/dtex.Secondly,by comparing the performance of five kinds of fiber materials,for 0.7～1.1μm particles,the filtration efficiency of profiled fiber filter material is significantly higher than that of polyester fiber(circular section)filter material,especially the comprehensive filtration performance of acetate fiber(trilobal section)filter material is the best,the filtration efficiency is 85.43%,the filtration resistance is 12 Pa,and the quality factor is 0.1605.The longitudinal and transverse breaking strength of polyester filter material were 499 N and 121.67 N,respectively.Then,the influence of acetic acid fiber mixing ratio on the performance of acetic acid/polyester mixed filter material was discussed.With the increase of cellulose acetate,the longitudinal breaking strength of the filter material decreased obviously,and the air permeability,filtration efficiency and filtration resistance showed a trend of first rising and then declining.When the mixing ratio is 5:5,the filtration efficiency of the filter material is the highest(89.65%),the filtration resistance is the highest(10 Pa),the quality factor is the highest(0.2268),and the comprehensive filtration performance of the filter material is the best.The filtration efficiency of cotton,viscose,acetic acid and Lyocell/polyester fiber mixed filter materials with the mixing ratio of 5:5 are all above 70%.The filtration efficiency of acetic acid/polyester fiber filter material is the highest(89.82%),the quality factor is the highest(0.2285),and the filtration performance is the best.The longitudinal and transverse breaking strength of Lyocell/polyester filter material were 244.86 N and 73.12 N,respectively.Finally,the effect of fiber orientation angle on the performance of acetic acid/polyester fiber composite filter material was discussed.With the increase of fiber orientation angleθ,the longitudinal strength of the filter material decreases continuously,while the transverse strength increases steadily,and the difference between the longitudinal and transverse directions decreases gradually.Whenθ=90°,the longitudinal and transverse strength of the filter material is close to(about 94 N);the filtration efficiency first increases and then decreases,while the air permeability and pressure drop are on the contrary.Whenθ=60°,the air permeability of the filter material is(1314.95mm/s)The filtration efficiency was the highest(95.33%),the filtration resistance was the lowest(8 N),and the quality factor was the highest(0.3830).