(632e) Aerosol Filtration Performance of Composites Containing Carbon Nanofibers Entrapped In Wet-Laid Nonwovens

Nonwoven materials have variety of applications in filters, textiles, medical disposables etc. In recent years, there has been a significant interest in using nanofibers with nonwoven materials for aerosol filtration. In this study, novel nano-nonwoven composites were made by combining commercially available vapor grown carbon nanofibers (VGCF) with nonwovens during wet-lay process. The as-received VGCF were in the form of clumps and aggregates, which have to be individualized in sovent/surfactant solution. The small aspect ratio of dispersed VGCF prevented their entrapment in the large pores of nonwovens. Flocking of VGCF dispersion provided an efficient and scalable route for entrapment of VGCF within nonwovens. The low density flocks retained the exfoliated structure of individualized VGCF after entrapment and processing. These novel composites can provide tunable pore sizes from nano to micro pores and therefore, have potential applications new areas of engineering such as nano-fiber reinforced polymer (n-FRP) composite and aerosol filtration by nanofibers. Roll to roll scalability was proven by making 700 sq. ft. of these composites in a pilot wet-lay machine. These composites with 3-dimensionally distributed nanofibers were tested for aerosol filtration efficiency. There was a significant enhancement in aerosol filtration performance which was attributed to the wall slip over entrapped nanofibers. The results of aerosol filtration, pressure drop and pore size distributions were used to deduce the micro and nano-structural attributes of these novel nonwovens composites.