High temperature zone‐drawing of nylon 66 microfiber prepared by CO₂ laser‐thinning

Abstract

ABSTRACT:A high temperature zone-drawing method was applied to a nylon 66 microfiber, obtained by using CO 2 laser-thinning, to develop its mechanical properties. The microfiber used for the high temperature zone-drawing was prepared by winding at 150 m min Ϫ1 the microfiber obtained by irradiating the laser at 4.0 W cm Ϫ2 to an original fiber with a diameter of 50 m, and had a diameter of 9.6 m and a birefringence of 0.019. The high temperature zonedrawing was carried out in two steps; the first drawing was carried out at a temperature of 230°C at supplying and winding speeds of 0.266 and 0.797 m min Ϫ1 , the second at 250°C at supplying and winding speeds of 0.266 and 0.425 m min Ϫ1 , respectively. The diameter of the microfiber decreased, and its birefringence increased stepwise with the processing. The high temperature zone-drawn microfiber finally obtained had a diameter of 4.2 m, a birefringence of 0.079, total draw ratio of 4.8, tensile modulus of 12 GPa, and tensile strength of 1.0 GPa. The wide-angle X-ray diffraction photograph of the drawn microfiber showed the existence of highly oriented crystallites.

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

“…It is well known that the molecular weight decreases by the thermal degradation occurred during the melt spinning. In the previous study,18 to examine whether the thermal degradation during the CO 2 laser‐irradiating occurred or not, the GPC measurements were carried out for the nylon 66 microfiber obtained by the CO 2 laser‐thinning. The results implied that molecular weight of the nylon 66 did not change before and after the laser irradiation.…”

“…A carbon dioxide (CO 2 ) laser‐thinning method developed by us could easily produce microfibers by irradiating a continuous‐wave CO 2 laser to fibers, such as poly(ethylene terephthalate) (PET),16 nylon 6,17 nylon 66,18 i‐polypropylene,19 poly( L ‐lactic acid) (PLLA),20, 21 and poly(ethylene ‐2,6‐ naphthalate) (PEN)22 fibers without highly skilled techniques. The microfiber obtained by winding on a spool in the winding speed range of 100–2500 m min −1 was monofilament microfiber with a uniform diameter.…”

Zone‐drawing and zone‐annealing of poly(L‐lactic acid) microfiber prepared by CO2 laser‐thinning method

“…SEM showed that the laser‐thinned (LT) microfibers had smooth surfaces not roughened by laser ablation, which were uniform in diameter. The change in the molecular weight during the CO 2 laser‐thinning hardly occurred as compared with its melt spinning 11…”

“…This method was previously applied to various polymers, such as PET and nylon 6 etc, to develop their mechanical properties12–16 and was suitable for improving the mechanical properties of fibers and films. The zone‐drawing and zone‐annealing method was also applied to the PET17 and nylon 6611 microfibers obtained by CO 2 laser‐thinning to develop their mechanical properties, and then high‐modulus and high‐strength microfibers were obtained.…”

Melt spinning of continuous fibers by cold air attenuation I: experimental studies

“…One approach is to heat the spinline by hot air or laser, such as in melt blowing and melt spinning with online laser heating. [4][5][6] With the increase of spinline temperature, the fibers tend to be attenuated more and usually finer fibers can be achieved. However, the fibers created from melt blowing are typically discontinuous with short fiber length.…”