Enhanced filtration characteristics of a PTFE foam-coated filter using PTFE nanofibers

Polytetrafluoroethylene (PTFE) is a bag filter material with limited options for fiber production methods because of its high melt viscosity. In this study, a new method for fabricating a PTFE composite filter with high filtration performance was proposed. PTFE nanofibers produced by electrospinning, were coated on the surface of the PTFE foam-coated filter, and heat-treated, resulting in the fabrication of PTFE composite filter. The optimal conditions for preparing PTFE nanofibers with a uniform fiber distribution were determined using a systematic approach. A uniform fiber morphology of the electrospun fibers was prepared by controlling the PTFE-Polyvinyl alcohol (PVA) mixing ratio and the electric field strength, and pure PTFE fibers were obtained by heat-treatment at an optimal temperature based on TGA, DSC, and FT-IR analyses. The filter quality factor of the resultant PTFE composite filter, which represents the filtration performance, was approximately twice that of the PTFE foam-coated filter for all particle sizes. Furthermore, the cleaning cycle and cleaning efficiency of the PTFE composite filter improved by 9% and 3.9–5.4%, respectively, compared to those of the PTFE foam-coated filter, which was closely related to high contact angles of water and oil.