Isotactic polypropylene microfiber prepared by continuous laser‐thinning method

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%

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

Karacan

Benli

2011

“…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.…”

Section: Introductionmentioning

confidence: 99%

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

Suzuki

Yamada

2010

Self Cite

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.

“…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.…”

Section: Introductionmentioning

confidence: 99%

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

Suzuki¹,

Hasegawa²

2006

Self Cite

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.