Poly(ethylene‐2,6‐naphthalate) nanofiber prepared by carbon dioxide laser supersonic drawing

Abstract

Poly(ethylene-2,6-naphthalate) (PEN) nanofiber was prepared by a carbon dioxide (CO 2 ) laser supersonic drawing. The CO 2 laser supersonic drawing was carried out by irradiating the laser to the as-spun PEN fiber in a low-temperature supersonic jet. The supersonic jet was generated by blowing off air into a vacuum chamber from a fiber supplying orifice. The flow velocity from the orifice can be estimated by applying Graham's theorem from the pressure difference between the atmospheric pressure and the pressure of the vacuum chamber. The fastest flow velocity estimated was 396 m s À1 (Mach 1.15) at a chamber pressure of 6 KPa. The nanofiber obtained at Mach 1.15 was the oriented nanofibers with an average diameter of 0.259 lm, and its draw ratio estimated from the diameters before and after the drawing reached 430,822 times. The CO 2 laser supersonic drawing is a new method to make nanofiber without using any solvent or removing the second component.

Broad poly(ethylene terephthalate) nanofiber sheet prepared by CO 2 laser supersonic continuous multi-drawing

“…Table 2 Cold crystallization temperature (T cc ), melting point (T m ), degree of crystallinity (X c ) and density (r) estimated from X c for the nanofiber sheets drawn by varying chamber pressure at a laser power of 20 W and by varying the laser power at a chamber pressure of 20 kPa. Chamber pressure/kPa Laser power/W 20 30 40 50 60 15 20 25 30 T cc / C 136 121 122 122 122 122 123 121 122 122 T The draw ratio (l) of the drawn fiber is expressed as [12], Fig. 9 shows the dependence of the trans/gauche ratio, the degree of crystallinity (X c ), and the melting point (T m ) on the draw ratio (l) for nanofiber sheets obtained by varying P L and p ch at L c ¼ 8 cm.…”

“…CLSD has already been applied to prepare nanofibers of poly(Llactic acid) [1], poly(ethylene terephthalate) (PET) [11], poly(ethylene-2,6-naphthalate) [12], ethylene tetrafluoroethylene [13], nylon 66 [14], and poly(phenylene sulfide) [15]. The nanofibers obtained are infinitely long because large plastic deformation accompanied by stable necking occurs during CLSD.…”

Ethylene tetrafluoroethylene nanofibers prepared by CO2 laser supersonic drawing

“…This closed-system technique also offers superior environmental safety than electrospinning and melt blowing, which are performed in open systems. CLSD has been used to produce poly(L-lactic acid) [16], polyethylene terephthalate [17], poly(ethylene-2,6-naphthalate) [18], poly(glycolic acid) [19], and isotactic polypropylene [20] Ethylene tetrafluoroethylene (ETFE) is a thermoplastic fluororesin that is formed from the copolymers tetrafluoroethylene (C 2 F 4 ) and ethylene (C 2 H 4 ). It is chemically resistant and has electrical properties equivalent to those of poly(tetrafluoroethylene) (PTFE), poly(tetrafluoroethylene-co-perfluoropropyl vinyl ether) (PFA), and poly(tetrafluoroethyleneco-hexafluoropropylene) (FEP), which are typical fluororesins.…”

Characterization of Fluoropolymer Nanofiber Sheets Fabricated by CO2Laser Drawing without Solvents

“…Therefore, we have reported a carbon dioxide (CO 2 ) laser supersonic drawing (CLSD) as a nanofiber manufacturing method. − At first, we prepared a chamber (box) which made a thin hole through the upper part. Then, vacuuming the chamber, airflow (supersonic velocities) occurs near the hole by a difference of atmospheric pressure.…”

“…Thus, this device is considered to have an environmental benefit. We have already reported fabricated nanofibers in poly(ethylene terephthalate) (PET), poly(ethylene-2,6-naphthalate) (PEN), poly (L-lactic acid) (PLLA), and poly(glycolic acid) (PGA) by the use of CLSD and CO 2 laser supersonic multidrawing (CLSMD). − …”