Nylon 6 microfiber obtained by a continuous‐thinning method with a carbon dioxide laser

Abstract

ABSTRACT:We succeeded in producing nylon 6 microfibers with a continuous-thinning method with a carbon dioxide (CO 2 ) laser. A laser-thinning apparatus used to continuously prepare microfibers was developed in our laboratory; it consisted of spools supplying and winding the fibers, a continuous-wave CO 2 -laser emitter, a system supplying the fibers, and a traverse. The laser-thinning apparatus produced microfibers in the range of 100 -2500 m min Ϫ1 . The diameter of the microfibers decreased as the winding speed increased, and the birefringence increased as the winding speed increased. When microfibers, obtained through the laser irradiation (at a power density of 19.8 W cm Ϫ2 ) of the original fiber supplied at 0.32 m min Ϫ1 , were wound at 848 m min Ϫ1 , they had a diameter of 3.2 m and a birefringence of 47 ϫ 10 Ϫ3 . The draw ratio calculated from the supplying and winding speeds was 2650ϫ. Scanning electron microscopy showed that the microfibers obtained with the laser-thinning apparatus had smooth surfaces not roughened by laser ablation that were uniform in diameter. Wideangle X-ray diffraction photographs of the microfibers wound at 566 and 848 m min Ϫ1 showed equatorial and meridional reflections due to the ␥ from. These reflections gradually became clear as the winding speed increased. The developed apparatus more easily produced microfibers than conventional technologies, such as conjugate spinning, islands-in-a-sea fiber spinning, melt blowing, and flash spinning.

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

“…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.…”

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

“…A laser‐thinning method producing microfiber by irradiating a carbon dioxide (CO 2 ) laser to fibers was developed by us, and an apparatus for the CO 2 laser‐thinning is able to wind the microfiber as a monofilament, at winding speeds ranging from 100 to 2500 m min −1 . The laser‐thinning method has already been applied to a poly(ethylene terephthalate) (PET),5 nylon 6,6 isotactic polypropylene (i‐PP),7 nylon 66,8 and poly( L ‐lactic acid) fibers,9 and the microfibers with diameter range of 1.5–5 μm were obtained.…”

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

“…The CO 2 laser‐thinning method easily yields microfibers without using highly skilled techniques, and it is suitable for producing microfibers of various polymers at a small scale. The CO 2 laser‐thinning method was previously applied to poly(ethylene terephthalate) (PET),5, 6 nylon 6,7 nylon 66,8 isotactic polypropylene,9 and poly( L ‐lactic acid) (PLLA),10 and then their microfibers with a diameter of about 2 μm were obtained. SEM showed that the laser‐thinned (LT) microfibers had smooth surfaces not roughened by laser ablation, which were uniform in diameter.…”

“…Although the CO 2 laser‐thinning was characterized by the plastic flow accompanied by a molecular orientation and a strain‐induced crystallization, the mechanical properties of the obtained microfiber were insufficient because of the lack of the highly oriented amorphous chains and crystallites 5–10. Therefore, it was necessary to draw and anneal the microfiber obtained to improve its mechanical properties.…”