A series of ultrahigh molecular weight polyethylenes with viscosity-average molecular weights in the range of 1.6⁻5.6 × 10⁶ have been prepared by using a novel Ziegler⁻Natta-type catalytic system-TiCl₄/2,2'-dimethoxy-1,1'-binaphthalene/Et₃Al₂Cl₃/Bu₂Mg at different temperatures (Tpoly) in the range between 10 and 70 °C in toluene. The morphology of the nascent reactor powders has been studied by scanning electron microscopy, wide-angle X-ray diffraction, and the DSC melting behavior. Polymers are suitable for the modern processing methods-the solvent-free solid-state formation of super high-strength (tensile strength over 1.8⁻2.5 GPa) and high-modulus (elastic modulus up to 136 GPa) oriented film tapes. With decrease of Tpoly, the drawability of the reactor powders increased significantly.
Keywords: UHMWPE; Ziegler-Natta catalysts; solvent-free processing.