Effects of Annealing on the Structure and Properties of a Melt-Blown Nonwoven Fabricated with Polypropylene and Poly-(Ethylene Terephthalate) Extruded Simultaneously from Nozzles of Different Diameters

Abstract Melt-blown (MB) nonwoven fabrics are made by mixing thick poly(ethylene terephthalate) (PET) fibers with polypropylene fibers to induce special functionality. However, their production is complex. In this study, a simpler process in which PET and polypropylene were extruded simultaneously from large and small nozzle holes, respectively, was developed. The resulting nonwoven was annealed for 5–15 min. The effects of the PET fibers and the annealing time on the structure and physical properties of the nonwoven were investigated. The proportion of the fibers with a diameter greater than 30 µm increased, indicating that the extruded PET produces thick fibers. The PET crystallinity increased from 6 to 45% with annealing time. Furthermore, the compressibility of the nonwoven decreased and its compression–recovery rate slightly increased with annealing time. The above changes in compression ability appear to be caused by the increase in the initial elastic modulus of the PET fibers owing to the increase in their diameter and crystallinity.