Polymer composite materials based on the Moplen HP400R polypropylene matrix with a filler from walnut shell flour with 30, 40 and 50% content and 200-315 µm and 315-443 µm fraction were produced by the injection method. The effect of filler content was analysed on the processing properties of the composites such as: MFR Melt Flow Rate and the MVR Melt Volume-flow Rate, as well as the temperature of the filler flour decomposition using the TGA thermogravimetric analysis method. The following was also determined: density, hardness, tensile strength and stiffness modulus of elasticity of the materials in question. The obtained composite material was characterised by low density, which increased with the rising filler content. It was found that the applied natural filler has increased the hardness and stiffness modulus of the composite and decreased the tensile strength.

The article presents the results of research concerning the effect of anthracite dust with 10%, 20%, 30%, 40% and 50% content in composites with a polypropylene matrix on selected properties. Hardness was examined with the Shore’s D method; stiffness, tensile strength as well as (MFR) Melt Flow Rate and (MVR) Melt Volume Rate of the investigated material were evaluated; wettability of the obtained material was also determined. Surface and volume resistivity were also investigated; the thermal properties of the filler were determined by thermogravimetric analysis (TGA). It was found that the investigated polypropylene composites filled with anthracite dust are hydrophobic materials and the composite hardness and stiffness are growing along with the volumetric increase of anthracite. It was noted that anthracite reinforces the material to a limited extent.