Abstract
In order to manufacture high modulus PPTA fiber, dry-jet wet spinning was carried out at various spinning-speeds, and the fibers obtained were heat-treated at various temperatures and tensions. Morphological properties obtained were investigated corelated with the tensile loads, spinning-speeds and heat-treatment conditions. Initial modulus of PPTA fiber was efficiently increased with right combinanations of spinning-speed and heat-treatment conditions. The initial modulus was more predominately dependent upon the crystallinity than upon the orientation. In addition, the increase of initial modulus was found to be reached to practical maximum in the range of 80~88% of crystallinity, determined by W. Ruland method with WAXD. Consequently, it was investigated experimentally that the process condition could be recommended to be higher than 3.5 of spinning stretch ratio (S.S.R), 3.5 g/d of heat treatment tension, and 470 $^{\circ}C$ of heat-treatment temperature, for the sake of obtaining 80~88% of crystallinity in the spinning and heat-treatment process.
