Effect of Coagulation Bath Concentration on the Structure and Properties of Polyacrylonitrile as-Spun Fibers during Wet-Spinning

Abstract

The effect of coagulation bath concentration on the structure and properties of as-spun fibers was systematically analyzed by means of X-ray diffraction, electron microprobe analysis, and the measurement of boiling-water shrinkage, porosity, and mechanical properties analysis, etc. It showed that with the increase of the coagulation bath concentration, the degree of spin orientation and the crystallinity both increased, the microstructure became compact and homogeneous, and the cross section of as-spun fibers tended to be circular. As a result, the breaking tenacity of as-spun fibers and resultant precursors both increased. Adopting the optimizing coagulation bath technique parameters: DMSO/H2O system, coagulation bath temperature 60°C, coagulation bath concentration 65%, and the minus stretch ratio –30%, the precursors and carbon fibers with high performance were prepared.