PREPARATION AND PROPERTIES OF ULTRA HIGH MOLECULAR WEIGHT POLY (ETHYLENE TEREPHTHALATE) FIBERS

Abstract

The preparation of ultra high molecular weight poly (ethylene terephthalate) (U-PET) and the drawing behavior of solution spun fibers from U-PET were investigated. U-PET was prepared by solidstate polymerization of porous and fibrous aggregates which were prepared from commercially available PET. As-spun fibers from U-PET (intrinsic viscosity, IV=3.6dL/g) were prepared by the solution spinning method using a mixed solvent of hexafluoro-2-propanol and dichloromethane (50/50, v/v). The polymer solution (8wt%) was extruded at room temperature through a conical capillary die with a diameter of 0.2mm. As-spun fibers were drawn at room temperature, followed by a tensile drawing at 210°C in an air. By this draw technique, the fibers could be drawn up to draw ratio of 12. Such highly drawn fibers exhibited tensile modulus and strength of 270 and 17g/d, respectively. However, the IV retention after the hot-drawing was only 67% primarily due to hydrolysis and/or oxidative degradation during processing.