While there is interest in using kaolinite fillers in clay rubber compounds, employing microwave (MW) irradiation for clay mineral treatment is not yet commonplace. This study explores the chemical modification of kaolinite under the microwave heating, using copper acetate (CuAc) and silanes, either bis-[3-(triethoxysilyl)propyl]tetrasulfide (BTT) or (3-aminopropyl)triethoxysilane (APT), hydrolysed in solvents like ethanol or toluene. The experimental procedure utilized a microwave reactor fitted with a glassware module, maintaining a stable temperature of either 40°C or 80°C for a period of 60 or 240 minutes. To analyse of the modified kaolinite samples, a variety of analytical techniques were employed, such as Fourier transformed infrared spectroscopy (FT-IR), thermogravimetry/differential scanning calorimetry (TG/DSC), and the sessile drop (static) method. Additionally, rubber compounds were prepared with 10 phr and 30 phr (parts per hundred rubber) of chemical modified kaolinites. The research further included the impact of modified MW-kaolinites on the curing characteristics (M_L, M_H, t₉₀), mechanical (TS_b, E_b), and physical properties (hardness, rebound elasticity) of sulphur-cured compounds contained Standard Malaysian Rubber (SMR). Replacing the traditional filler carbon black (N339) with 10 and/or 30 phr of modified kaolinites as fillers resulted in reduced viscosity of the compounds and somewhat increased vulcanization duration, particularly for Cu²⁺ kaolinite sample. Furthermore, compounds containing the same proportions of all modified kaolinite samples demonstrated increased elongation at break and tensile strength comparable to the standard compound, suggesting improved processing and elasticity of rubber compounds containing containing kaolinite modified by the proposed procedures.

Acknowledgement: The authors would like to thank the Slovak Grant Agency KEGA for financial support (KEGA 008TnUAD-4/2025). The work was supported by the project Advancement and support of R&D for  “Centre for diagnostics and quality testing of materials” in the domains of the RIS3 SK specialization, code NFP313010W442.