Polymer–Polymer Blends of Ultrahigh-Molecular-Weight Polyethylene and Low-Molecular-Weight High-Density Polyethylene: Synthesis, Morphology, and Properties

Polymer–polymer blends of ultrahigh-molecular-weight polyethylene (UHMWPE) and of low-molecular-weight high-density polyethylene (LMWPE) that contained 30, 50, and 80 wt % UHMWPE, were synthesized in a two-stage polymerization of ethylene over a rac-Me2Si(Ind)2ZrCl2/methylalumoxane catalyst. The conditions of the stage were chosen based on the results of study of one-stage polymerization of ethylene in the temperature range 30–80°C. The order of introduction of the components to the UHMWPE/LMWPE or LMWPE/UHMWPE polymer blend was inverted by changing the sequence of the stages. The melting points and degrees of crystallinity of the polymer products were determined. The morphologies of the surfaces of the nascent particles of UHMWPE/LMWPE and LMWPE/UHMWPE blends were compared with scanning electron microscopy. The deformation and strength properties, abrasive wear resistance, and melt flow indices of the materials were studied as functions of the order of introduction of the components and the contents of the fractions in the polymer–polymer blends.