Microstructure and mechanical properties of hot-air drawn poly(ethylene terephthalate) fibers

✍ Scribed by Akihiro Suzuki; Yukio Nakamura; Toshio Kunugi

• Publisher: John Wiley and Sons
• Year: 1999
• Tongue: English
• Weight: 276 KB
• Volume: 37
• Category: Article
• ISSN: 0887-6266
• DOI: 10.1002/(sici)1099-0488(19990715)37:14<1703::aid-polb14>3.0.co;2-p

✦ Synopsis

Hot-air drawing method has been applied to poly(ethylene terephthalate) (PET) fibers in order to investigate the effect of strain rate on their microstructure and mechanical properties and produce high-performance PET fibers. The hot-air drawing was carried out by blowing hot air controlled at a constant temperature against an as-spun PET fiber connected to a weight. As the hot air blew against the fibers weighted variously at a flow rate of about 90 ᐉ/min, the fibers elongated instantaneously at a strain rate in the range of 2.3-18.7 s Ϫ1 . The strain rate in the hot-air drawing increased with increasing drawing temperature and applied tension. When the hot-air drawing was carried out at a drawing temperature of 220°C under an applied tension of 27.6 MPa, the strain rate was the highest value of 18.7 s Ϫ1 . A draw ratio, birefringence, crystallite orientation factor, and mechanical properties increased as the strain rate increased. The fiber drawn at the highest stain rate had a birefringence of 0.231, degree of crystallinity of 44%, tensile modulus of 18 GPa, and dynamic storage modulus of 19 GPa at 25°C. The mechanical properties of fiber obtained had almost the same values as those of the zone-annealed PET fiber reported previously.