Isotactic polypropylene microfiber prepared by carbon dioxide laser‐heating

Dry and wet annealing of isotactic polypropylene fibers was carried out under constant length at 120°C in air and in glycerine environments with annealing times ranging from 1 to 30 h. A detailed analysis of the infrared spectrum of samples annealed, especially in air, showed clear evidence of the surface oxidation as indicated by the appearance of oxygen containing functional groups. Annealing was found to lead to an improved structural organization as indicated by the crystallinity, crystallite size, and orientation measurements using X‐ray diffraction and infrared spectroscopy methods. Analysis of the X‐ray diffraction measurements showed a gradual transformation of metastable smectic phase to a more stable α‐monoclinic phase with increasing annealing time. Crystallinity, crystallite size, and orientation measurements performed for the samples annealed in air and in glycerine environments showed no distinct difference. Mechanical properties of the annealed samples were influenced by the annealing environment. Annealing in an air environment resulted in a continuous loss of tensile strength up to the annealing time of 12 h due to an oxidation related chain scission mechanism. On the other hand, annealing in glycerine environment resulted in a continuous and gradual increase of tensile strength without loss of physical form up to the annealing time of 30 h. It is suggested that wet annealing in glycerine environment should be used to obtain improved tensile strength values. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

The role of dry and wet isothermal annealing treatment on the structure and the mechanical properties of isotactic polypropylene fibers

Karacan

Benli

2011

“…The applied tension in the CO 2 laser‐thinning was in the range of 1/100 to 1/1000 of the applied tension in a laser‐heating zone‐drawing, and the power density in the CO 2 laser‐thinning was about five times larger that that in the CO 2 laser‐heating zone‐drawing 1, 2. The CO 2 laser‐thinning method was already applied to a poly(ethylene terephthalate) (PET),3, 4 a nylon 6,5 and an isotactic polypropylene (i‐PP)6 fibers. The PET microfiber with a diameter of 1.5 μm, the nylon 6 microfiber with a diameter of 1.9 μm, and the i‐PP microfiber with a diameter of 1.8 μm were obtained.…”

Section: Introductionmentioning

confidence: 99%

“…The polymer that is possible to produce the microfiber by these methods is limited to PET, nylon, and polyethylene. On the other hand, it is possible to produce all thin thermoplastic polymers by using the developed apparatus because the thinning by the laser‐heating can be regarded as a die‐less spinning 1–6…”

Section: Introductionmentioning

confidence: 99%

Isotactic polypropylene microfiber prepared by continuous laser‐thinning method

Suzuki¹,

Narusue²

2005

Self Cite

An isotactic polypropylene (i-PP) microfiber was continuously produced by using a carbon dioxide (CO 2 ) laser-thinning apparatus developed in our laboratory. The CO 2 laser-thinning apparatus could wind up the obtained microfiber in the range of 100 m min Ϫ1 to 2500 m min Ϫ1 . The diameter of the microfiber decreased and its birefringence increased with increasing winding speed. When the microfiber obtained by irradiating the CO 2 laser operated at a power density of 31.8 W cm Ϫ2 to the original fiber supplied at 0.30 m min Ϫ1 was wound at 1,387 m min Ϫ1 , the obtained microfiber had a diameter of 3.5 m and a birefringence of 25 ϫ 10 Ϫ3 . The draw ratio calculated from the supplying and the winding speeds was 4,623-fold. The SEM photographs showed that the obtained microfibers had a smooth surface without a surface roughened by a laser-ablation and were uniform in diameter. The wide-angle X-ray diffraction photographs of the microfibers wound at 848 and 1,387 m min Ϫ1showed the existence of the oriented crystallites.

“…A thinning method with a continuous‐wave carbon dioxide (CO 2 ) laser has already been applied to poly(ethylene terephthalate) (PET),1, 2 nylon 6,3 and isotactic polypropylene (i‐PP)4 fibers, and it is effective in preparing their microfibers. When a high‐output‐power laser is used to irradiate a fiber applied at an extremely low tension, its microfiber is easily obtained.…”

Section: Introductionmentioning

confidence: 99%

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

Suzuki

Kamata

2004

Self Cite

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.