Effect of melt flow modifier on the physico-mechanical properties of a polymer composite based on secondary polypropylene and aluminosilicate microspheres

Thermoplastics in the recycling process are characterized by mechanical and thermo-oxidative degradation, which leads to deterioration of the operational properties of finished plastic products. A possible option for giving the secondary raw material optimal characteristics during processing may be the inclusion of aluminosilicate microspheres and modifiers that increase the fluidity of the melt. This paper presents the results of the study of rheological and physico-mechanical properties of polymer composites based on secondary polypropylene filled with aluminosilicate microspheres in the presence of stearic acid. It is shown that stearic acid increases the fluidity of the melt, improves technological performance during mechanical processing, including promotes uniform distribution of particles of aluminosilicate microspheres in the polymer volume. The optimal concentration of stearic acid is 0.5 % by weight, at which there is a maximum increase in the melt flow rate, a decrease in tensile strength of no more than 16 %, as well as an increase in resistance to dynamic impact without a significant change in the elastic modulus characterizing the stiffness of the material.