APPLICATION OF CONTINUOUS ZONE-DRAWING ZONE-ANNEALING METHOD TO POLY(ETHYLENE-TEREPHTHALATE) FIBERS/

A continuous zone-drawing/zone-annealing method was applied to poly(et hylene terephthalate) fibers in order to improve their mechanical prop erties. Apparatus used for this treatment was assembled in our laborat ory. The continuous zone-drawing treatment was carried out at a drawin g temperature of 103 degrees C under an applied tension of 6.6 MPa to fully orient amorphous chains in the drawing direction without inducin g thermal crystallization. The continuous zone-annealing treatment was carried out twice at an annealing temperature of 160 degrees C under 102.2 MPa and at 183 degrees C under 161.1 MPa to crystallize the high ly oriented amorphous chains. The fiber was continuously drawn and ann ealed at a rate of 420 mm/min. The fiber obtained had a birefringence of 0.260, a degree of crystallinity of 55%, a tensile modulus of 18 GP a, and a storage modulus of 21 GPa at 25 degrees C. Despite the large difference in the treating speed between the continuous zone-annealing and zone-annealing, their values are approximately equal to those of the zone-annealed PET fiber that was reported previously. (C) 1998 Joh n Wiley & Sons, Inc.