Mechanical properties and superstructure of poly(ethylene terephthalate) fibers zone‐drawn and zone‐annealed by CO₂ laser heating

Abstract

ABSTRACT:A laser-heating zone-drawing and zone-annealing method using a continuous-wave carbon dioxide laser was applied to poly(ethylene terephthalate) (PET) fiber to improve its mechanical properties. The as-spun fiber was zone-drawn under a applied tension ( a ) of 4.44 MPa at a laser power density (PD) of 6.08 W cm Ϫ2, and then the laser-heated zone-drawn fiber was zone-annealed. The laser-heating zone-annealing was carried out in three steps: the first annealing was carried out under a ϭ 139 MPa at 4.83 W cm Ϫ2 ; the second annealing was carried out under a ϭ 283 MPa at 4.83 W cm Ϫ2 , and the third annealing was carried out under a ϭ 432 MPa at 3.45 W cm Ϫ2 . The surface temperature distribution of the fiber irradiated with the CO 2 laser was measured by using an infrared thermographic camera equipped with a magnifying lens. The relation between the laser power and the surface temperature of the fiber became clear in the laser-heating zone-drawing and the laser-heating zone-annealing. The fiber obtained finally had a birefringence of 0.239, a degree of crystallinity of 55%, a tensile modulus of 19.8 GPa, and a storage modulus of 25.7 GPa at 25°C. In FTIR measurements, a trans conformation increased with the processing, but a gauche one decreased. The laser-heating zone-drawing and zone-annealing method was found to be effective in producing the PET fiber with high modulus and high strength.

Structure–properties relations of the drawn poly(ethylene terephthalate) filament sewing thread

“…Therefore, the amount of gauche conformations diminishes and proceeds to trans conformations. By laser-heating zone-drawn of the PET spun fiber, Suzuki and Mochiduki 27 found by FTIR measurements that a trans conformation increased and a gauche one decreased. However, drawing above the glass transition temperature increases the tensile deformation, which probably causes the straightening and sliding of the strained intrafibrillar tie molecules, which proceeds to the crystalline domains.…”

High-Strength PET Fibers Produced by Conjugated Melt Spinning and Laser Drawing

“…The key feature of the zone-drawing process is the effective drawing of molecular chains by the rapid local heating of the fiber. Irradiation of a CO 2 laser can heat the fiber far more rapidly than the heat transfer used for the ordinary drawing process (Suzuki et al, 2001;Okumura et al, 2003). Thus, we concluded that laser drawing would be the best choice for retaining the structural features of conjugated fibers in the drawing process.…”

Isotactic polypropylene microfiber prepared by carbon dioxide laser‐heating

“…[1][2][3][4][5][6][7][8] We applied a continuous-wave carbon dioxide (CW CO 2 ) laser to poly(ethylene terephthalate) (PET) 9 and nylon 6 10 fibers to improve their mechanical properties. The drawing and annealing by using the CW CO 2 laser was found to be effective in producing fibers with high modulus and high strength.…”