INVESTIGATION OF PHYSICO-MECHANICAL AND RHEOLOGICAL CHARACTERISTICS OF NANOCOMPOSITES OF ULTRAHIGH-MOLECULAR POLYETHYLENE

Abstract

The paper presents the results of a comparative study of the physicomechanical and rheological characteristics of nanocomposites of ultrahigh-molecular-weight polyethylene, grade GUR 4120 (Ticona) with nanocrystalline silica with a dispersity of 20 nm (0.05% - 0.2%), nano scale aluminum oxide of the mark “Nafen” 10 ... 20 nm (0.1%) and carbon nanotubes Tuballmatrixbeta (0.1%). It was established that the introduction of silicon dioxide in the optimal concentration of 0.1 ... 0.15% contributes to an increase in the tensile strength by 44%, and the final modulus of elasticity by 46%. The limit of forced elasticity and the initial modulus of elasticity are more influenced by carbon nanotubes (an increase of 23%). However, the results in this case are characterized by a significant scatter of values. Nanofibres of the Nafen brand provide growth of strength by 22%, final elastic modulus by 28.6%. The dependence of the complex viscosity of composites at a temperature of 180 °C on the angular velocity is described by the Ostwald de Ville power equation. The introduction of nanoscale modifiers leads to an increase in the consistency coefficient of ultrahigh molecular weight polyethylene by 3.9 ... 6.6 times, with the flow index increasing only by 1.02 ... 1.28 times. It is shown that the use of optimal (0.1 ... 0.15%) concentrations of nanocrystalline silicon dioxide, aluminum oxide nanofibers and carbon nanotubes combined with ultrahigh-molecular polyethylene by mechanochemical activation in a planetary ball mill, significantly improves physical and mechanical characteristics of the latter. In this case, a more effective modifier is nanocrystalline silicon dioxide. The significant effect of ultra-low concentrations of nanoscale modifiers is apparently due to the formation of a spatial network of physical bonds in the composite volume, which persists even at a temperature of 180 ° C, as evidenced by the results of rheological tests.