Structure and Properties of Poly(ethylene terephthalate) Fiber Webs Prepared via Laser-Electrospinning and Subsequent Annealing Processes

Abstract

Melt-electrospinning is an eco-friendly method for producing ultra-fine fibers without using any solvent. We prepared webs of poly(ethylene terephthalate) (PET) through melt-electrospinning using CO2 laser irradiation for heating. The PET webs comprised ultra-fine fibers of uniform diameter (average fiber diameter = 1.66 μm, coefficient of variation = 19%). The co-existence of fibers with high and low molecular orientation was confirmed through birefringence measurements. Although the level of high orientation corresponded to that of commercial highly oriented yarn, crystalline diffraction was not observed in the wide-angle X-ray diffraction (WAXD) analysis of the webs. The crystallinity of the webs was estimated using differential scanning calorimetry (DSC). The fibers with higher birefringence did not exhibit any cold crystallization peak. After annealing the web at 116 °C for 5 min, a further increase in the birefringence of the fibers with higher orientation was observed. The WAXD results revealed that the annealed webs showed crystalline diffraction peaks with the orientation of the c-axis along the fiber axis. In summary, the formation of fibers with a unique non-crystalline structure with extremely high orientation was confirmed.

Bamboo Charcoal/Poly(L-lactide) Fiber Webs Prepared Using Laser-Heated Melt Electrospinning

“…The LES apparatus used in the present study ( Figure 1 ) was composed of a CO 2 laser irradiation system (PIN-30R, Onizuka Glass Co., Ltd.; wavelength: 10.6 μm) and an electrospinning system (NEU-010, Katotech Co., Ltd., Kyoto, Japan) [ 20 , 21 ]. The raw fiber was fed by a feed roller at a constant feed rate of 28.8 mm/min through a stainless steel nozzle with inner and outer diameters of 0.31 and 0.57 mm, respectively.…”

“…To overcome these limitations, herein, a novel laser electrospinning (LES) method, that is, melt electrospinning with CO 2 laser irradiation for the rapid heating of polymers, was developed to fabricate ultrafine fibers and substantially suppress the thermal degradation of these fibers. In our previous studies, various ultrafine fibers were successfully produced via LES [ 20 , 21 ].…”

Planar or Biaxial Stretching of Poly(ethylene terephthalate) Fiber Webs Prepared by Laser-Electrospinning

“…Spun bonding, melt blowing, and electrospinning are widely used to produce nonwoven fabrics. In particular, the electrospinning method has been actively used to form nonwoven materials with submicron- and nanoscale fibers [ 1 , 2 , 3 , 4 , 5 , 6 , 7 , 8 , 9 , 10 , 11 , 12 , 13 , 14 , 15 , 16 , 17 , 18 ]. Electrospinning can be classified into solution and melt types.…”

“…Melt electrospinning has the advantages of lower toxicity and cost reduction compared to conventional solution electrospinning [ 16 ]. In melt electrospinning, electric heaters and carbon dioxide lasers are mainly used as heat sources [ 7 , 8 , 9 , 10 , 11 , 12 , 13 , 14 , 15 , 16 , 17 , 18 ].…”

“…In previous studies from our group, the melt-electrospinning technique with CO 2 laser irradiation, i.e., laser-heated electrospinning (LES), was used to investigate the formation of submicron- and nanoscale fibers [ 10 , 11 , 12 , 13 , 14 , 15 , 17 , 18 ]. We applied LES to thermoplastic polymeric materials, such as poly(L-lactide) (PLLA), PLLA copolymers, and PLLA-based composites, to generate webs consisting of relatively uniform fibers with an average diameter and coefficient of variation (CV) of approximately 700–1000 nm and less than 50%, respectively [ 15 , 17 ].…”