부산대학교 도서관

The rheological features of the melt flow of the initial low-density polyethylene and its filled composites with aluminum powder are studied. The effect the filler concentration, temperature, and shear rate on the composite rheology is explored. To improve the compatibility of metal-polymer systems, a compatibilizer representing a graft copolymer of low-density polyethylene with content of 5.8 wt % maleic anhydride is used. The values of the melt flow index (MFI) of low-density polyethylene are determined depending on the concentration of aluminum powder. The filler concentration is varied in the range of 0.5–30 wt %. It is shown that 0.5 wt % of aluminum powder leads to the maximum MFI of the composites. The flow curves and the dependence of the effective viscosity on the shear rate of the initial low-density polyethylene and composites with content of 0.5 and 5.0 wt % aluminum powder are determined. A theoretical justification of the regularities of changes in rheological properties is proposed. The dependence of the change in the effective viscosity of the melt on temperature in Arrhenius coordinates is established. On the basis of the curves obtained, the values of the apparent activation energy of the viscous flow are determined. It is determined that the introduction of the filler results in an increase in the activation energy of the viscous flow. A temperature-invariant characteristic of the viscosity properties of composites is constructed, allowing one to predict the change in the value of this indicator at high shear rates, close to their processing by extrusion and injection molding.