PREPARATION OF HIGH MODULUS POLY(VINYL ALCOHOL) BY DRAWING

The preparation of PVA films and fibers with high modulus and high strength was examined. The high drawing was attained when both the drawing just before melting and the relaxation at room temperature were repeated. The maximum draw ratio was 40 for the films prepared from the gels of high molecular weight (HMW) a‐PVA (DP ‐ 12000)/water/dimethyl sulfoxide (DMSO) system (water/DMSO = 20/80). The degree of crystallinity of tthe dried gels prepared from the PVA/ethylene glycol (EG) system was high, 40–50%, and independent on the tacticity of PVA. The modulus of the fibers, prepared from the gels of HMW s‐PVA (DP = 15300)/EG system, drawn 15 times to its original length was the highest (120 GPa). Copyright © 1990 John Wiley & Sons, Inc.