Rheological properties of composites based on aluminum hydroxide and lowand high-density polyethylene blends
The results of the study of the rheological characteristics of low- and high-density polyethylene blend in the ratio of 50:50 and its aluminium hydroxide-filled composites are presented. The influence of the concentration of aluminium hydroxide, temperature and shear stress on the regularity of changes of the effective viscosity and shear rate has been established. Rheograms of low- and high-density polyethylene blend in the ratio of 50:50 and composites based on it are presented. The dependence of viscosity on temperature in Arrhenius coordinates is determined, according to which the “apparent” activation energy of viscous flow for the initial low- and high-density polyethylene blend and its aluminium hydroxide-filled composites varies in the range of 6 - 19 and 11 -31 kJ/mol, respectively. A universal temperature-invariant characteristic of the viscosity properties of low-and high- density polyethylene blend in the ratio of 50:50 and its aluminium hydroxide-filled composites, which allows to predict the change in the melt viscosity of composites in a wide range of shear rates and stresses, was drawn. It is shown that with an increase in the concentration of aluminum hydroxide in the polymer mixture to 5wt.% the value of the shear rate remains almost unchanged relative to the initial low- and high-density polyethylene blend (50/50). Rheological studies of the melt of polymer materials were carried out in accordance with the standard ASTM D1238 on capillary rheometer CEAST MF50 (INSTRON, Italy) in the temperature range of 190 - 250 °C and in the load range of 3.8 - 21.6 kg.