Effect of Molecular Weight Characteristics on the Supramolecular Structure and Mechanical Properties of Polyethylene Synthesized on a VCl3-Based Catalyst

The effect of molecular weight characteristics of high-density polyethylenes in a wide molecular weight range from ultrahigh to low molecular (polyethylene, close to the brittleness threshold), as well a reactor polymer composite ultrahigh-molecular-weight PE–HDPE, which were synthesized in the presence of a heterogeneous catalyst based on VCl3, on the structural parameters and deformation–strength properties of polyethylene was studied. It was shown that the supramolecular structure parameters and deformation–strength properties of the synthesized polyethylenes correlate with their molecular weight characteristics. Polymers with a MW lower than that of ultrahigh-molecular-weight PE and a reactor polymer blend ultrahigh-molecular-weight PE/HDPE are characterized by bimodal MWDs with a wide Mw/Mn. With decreasing MW, the proportion of a high-molecular-weight fraction decreases. As a result of structural changes, the lamellar long period Lp decreases due to the thinning of the intercrystalline amorphous gap La, which increases the plasticity of the material and decreases its strength.