A hot-air (HA) drawing method has been applied to poly(ethylene-2,6-naphthalate) (PEN) fibers in order to improve their mechanical properties. The HA drawing was carried out by blowing hot-air controlled at a constant temperature against an original PEN fiber connected to a weight. As the hot-air blew against the fiber at a flow rate of 90 l/min, the fiber elongated instantaneously at a strain rate in the range from 15.9 to 25.2 s 21. The strain rate during the HA drawing increased with increasing drawing temperature and applied tension. When the HA drawing was carried out at a drawing temperature of 2508C under an applied tension of 17.4 MPa, the strain rate had the highest value of 25.2 s 21. Draw ratio, birefringence, crystallite orientation factor, and mechanical properties increased as the strain rate increased. The fiber drawn at the highest strain rate had a birefringence of 0.436, degree of crystallinity of 45%, tensile modulus of 29 GPa, and dynamic storage modulus of 30 GPa at 258C. The mechanical properties of the fiber obtained had almost the same values as those of zone-annealed PEN fibers.
Посилання на статтю:
Microstructure and mechanical properties of hot-air drawn poly(ethylene-2,6-naphthalate) fibers / Akihiro Suzuki, Yukio Nakamura, Toshio Kunugi // Polymer. – 1999. – N 40. – P. 5043–5049.