The impact of post-radiation high-temperature shear grinding on the thermal and mechanical properties of polypropylene

The effect of input doses of 60 Co γ-radiation from 80 to 12,000 kGy on the thermophysical properties and thermal stability of samples of polypropylene granules and powder obtained by high temperature shear grinding of irradiated granules, as well as on the tensile strength properties of a plate made from irradiated granules and their corresponding powders, was studied. The thermophysical properties of the powder are determined by the changes introduced by radiation into the initial polymer granules. The effects of radiation in air (environments with oxygen) were studied. Grinding redistributes oxygen-containing functional groups from the surface layer of irradiated granules throughout the entire volume of the obtained powder leading to the destruction of polymer chains as there is a component due to thermal destruction of radiolyzed polymer chains. High-temperature shear grinding of irradiated granules has a significant effect on the product powder, reducing its thermal stability but increasing the tensile strength of plates pressed from it at low absorbed doses. The current work shows that radiation treatment coupled with high temperature shear grinding could be a method for modifying the properties of polymers so that polypropylene waste can be processed for other applications. • Effect of γ-radiation followed by high temperature shear grinding (HTSG) of polypropylene (PP). • Measure thermophysical properties using thermomechanical analysis and differential scanning calorimetry. • Irradiation changes chemical, thermophysical, thermal, and other properties of irradiated granules and the HTSG powders. • Plates from irradiated HTSG powders have lower tensile strength. • HTSG of PP granules redistributes surface oxygen-containing functional groups into the entire volume.