Effect of the Structure of the Modifying Polyolefin Fraction on the Deformation and Strength Properties of Reactor Polymer Compositions Based on Ultrahigh Molecular Weight Polyethylene

The morphology and tensile properties of reactor polymer compositions based on ultrahigh molecular weight polyethylene (UHMWPE, M_w = 10⁶) with different contents of modifying polyolefin fractions have been studied. The compositions were obtained directly during the polymerization of ethylene using homogeneous catalysts. Modifying polyolefin fractions differed in their structure, molecular weight, and thermophysical properties and included linear HDPE with M_w = 5 × 10⁴ and 1.5 × 10⁵, as well as branched ethylene/hexene-1 copolymers with a 1-hexene content of 3, 10, and 20 mol %. The melting temperatures, the degrees of crystallinity of the materials and the dimensions of the crystallites were determined using the DSC and WAXS. The influence of morphology, physical and mechanical properties of modifying polyolefin fractions, their content on the stress-strain curves and tensile characteristics of reactor polymer compositions have been studied.