Structural difference of gel-spun ultra-high molecular weight polyethylene fibers affected by cold drawing process

The UHMWPE fibers with different cold drawing ratio (DR₀) were obtained from the industrial UHMWPE fibers production line. The effect of cold drawing before the extraction of paraffin oil process on final fibers was investigated by tensile testing, small angle X-ray scattering (SAXS) and wide angle X-ray diffraction (WAXD). The tensile strength and modulus with 5.0 DR₀ were 2.99 and 151.5 GPa, respectively, which were 13.3 % and 41.9 % higher than those with 1.5 DR₀. With the increase of DR₀, the values of average shish length decreased obviously, while the shish orientation increased and the apparent crystal size along two lattice directions ((110)_o and (200)_o) in UHMWPE fibers decreased. The increase of degree of orientation and crystallization were verified that better folded chains and amorphous chains were involved in forming shorter and better oriented shish.