화학공학소재연구정보센터
Industrial & Engineering Chemistry Research, Vol.51, No.30, 10117-10123, 2012
Characterization of Fluoropolymer Nanofiber Sheets Fabricated by CO2 Laser Drawing without Solvents
Nanofibers of tetrafluoroethylene-perfluoroalkyl vinylether (PFA) copolymer were prepared by irradiating PFA fibers with a CO2 laser under supersonic velocities. This is the only method to make PFA nanofibers without the use of solvents, because for the majority of methods for preparing nanofibers, they must be dissolved in a solvent and PFA fibers cannot be dissolved in most solvents, except special fluorinating reagents. The average fiber diameter of PFA nanofibers was approximately 273 nm. As a result, we developed a CO2 laser supersonic multidrawing (CLSMD) in a new way to produce PFA nanofibers in large quantities. CLSMD can make nanofibers continually in a wide area. The length, width, and thickness of pileup nanofiber sheets are 50 cm, 17 cm, and 70 pm, respectively. It was observed that nanofiber sheets have a higher melting point and degree of crystallinity than microfibers by differential scanning calorimetry (DSC) measurements and have larger crystallite size realized by wide-angle X-ray diffraction (WAXD) measurements. Moreover, it was considered that the interior of nanofiber sheets have oriented structurally and the strength of nanofiber sheets was higher than that of microfibers. Nanoparticles were evolved to the surface of nanofiber sheets by annealing.