APPLICATION OF A CONTINUOUS ZONE-DRAWING METHOD TO NYLON-66 FIBERS

A continuous zone-drawing (CZD) treatment was applied to nylon 66 fibr es in order to improve their mechanical properties. The CZD treatment was carried out at a drawing rate of 420 mm/min and in three steps; th e first CZD (CZD-1) at a drawing temperature of 210 degrees C under an applied tension of 30.3 MPa, the second (CZD-2) at 220 degrees C unde r 229.5 MPa, and the third (CZD-3) at 230 degrees C under 364.9 MPa. T he orientation factor of crystallites reached a high value of 0.960 wi th only the CZD-1 treatment, but that of an amorphous phase increased with the number of times in CZD treatment. The trans isomer content in creased during the CZD treatment, whereas the gauche decreased. The CZ D-3 fibre had a value of birefringence of 0.072, a degree of crystalli nity of 37%, a tensile modulus of 8 GPa, and a tensile strength of 1.2 GPa. (C) 1998 Elsevier Science Ltd. All rights reserved.