The work presents the results of a comprehensive study on obtaining compositions based on polypropylene and natural fillers modified by enzymatic preparations under high-shear forces. The experiment protocol includes determining the modification time and the ratio of water volume to the mass of natural filler (hydro modulus) during modification, which turned out to be different for each type of filler. Physical and mechanical analyses were conducted to evaluate the operational characteristics of the obtained composites, with particular attention given to comparing the modified compositions with their unmodified counterparts. The time and hydro module of the enzymatic modification of the natural fillers under consideration were investigated, which turned out to be different for each type of filler. It was found that surface modification of natural fillers improves mechanical properties; namely, the tensile strength of composites with wood and sunflower fillers increases by 10%, and the impact viscosity of composites also increases by 12% with wood and sunflower fillers. Water absorption decreases in composites, after 2 h boiling, with wood flour by 30% and with rice husk by 10%. After a 14-day test at room temperature, water absorption decreases by more than 30% in composites with rice husk. When determining the free surface energy of composites, it was found that the modification of the filler reduces the polarity of the composites in all samples, which can be interpreted as an improvement in the interaction between the filler and the polymer matrix. The findings of this research have important implications for the development of advanced polymeric materials that can be used in a wide range of applications, including automotive, aerospace, and construction industries. The results underscore the importance of surface modifications to optimize the properties of polymeric composites and provide valuable insights into the role of natural fillers in enhancing the performance of these materials.

This study investigates the effect of rice husk content (0–60 wt.%) on the thermal, mechanical and rheological properties of polypropylene composites prepared by extrusion and injection molding. A temperature-invariant approach was applied to analyze the viscoelastic properties, allowing the combination of data obtained at different temperatures. The results show that as the husk content increases, the elastic modulus and hardness rise linearly, while the impact strength and elongation at break significantly decrease. Composites with 40–50% filler exhibit a balanced combination of strength and stiffness, as confirmed by the summary data in the table (provide references). The application of the temperature-invariant viscosity method confirmed its effectiveness in evaluating the flow properties of composite melts. The obtained results have practical significance for the development of eco-friendly polymer materials with natural fiber fillers.

Light scattering composites based on polystyrene, polyethylene and glass hollow microspheres have been developed. Composites with the optimal ratio of light transmission and light scattering coefficients has been produced.