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이윤응,주창환,Lee, Youn-Eung,Joo, Chang-Whan 한국섬유공학회 2005 한국섬유공학회지 Vol.42 No.6
Nonwoven fabrics which have three dimensional microporous structure have been widely used for noise control in the civil and architecture fields. In this study, the sound absorption properties of the nonwoven fabrics produced by different manufacturing conditions were investigated using an impedance tube method. For the purpose of substitution of conventionally used sound absorber materials with polyester nonwovens, a theoretical model based on the microporous structure of nonwovens was established to predict the sound absorption coefficient(NAC) of nonwoven materials. In conclusion, it was found that the NAC significantly depended on the fiber fineness, web orientation and nonwoven thickness. The nonwovens composed of fine fiber, randomly oriented web and which have higher thickness showed definitely higher NAC than those of the opposite cases. Furthermore, the theoretical model established for the NAC of nonwovens was in good agreement with the experimental results, especially in the high frequency region.
신동호,이윤응,주창환,Shin, Dong-Ho,Lee, Youn-Eung,Joo, Chang-Whan 한국섬유공학회 2005 한국섬유공학회지 Vol.42 No.6
Most thermoplastic fibrous materials have low dielectric constant enabling direct bonding of the composing fibers by microwave heating. However, the bonding capability between nanofibers can be highly increased by blending additives having high dielectric constant. In this paper, nylon 66 nanofibers were produced with the carbon black particles, which have high permittivity, by the electrospinning method. The produced carbon black/nylon 66(CB/N) hybrid nanofiber webs of different carbon black contents were heated by the microwave system for different treatment times. The morphological structure and strength properties of CB/N hybrid nanofiber webs were investigated to verify their bonding behavior. The results showed that the bonding strength of pure nylon 66 nanofiber webs prepared by microwave heating was weak, but the bonding area at the contact point of nanofibers having carbon black increased with increasing microwave treatment tine. In spite of increasing bonding area, the bonding strength of CB/N nanofiber webs does not increase due to the decrease in fiber diameter.