Abstract
Nanoparticles have emerged as promising additives for developing advanced engine lubricants capable of withstanding high temperatures and oxidative stress. This study investigates the potential of silicon dioxide (SiO2) nanoparticles, surface-modified with KH570-Silane coupling agent, to enhance the oxidation resistance and thermal stability of lubricants and biolubricants. Thermal and oxidative properties were evaluated using thermogravimetric analysis (TGA), derivative thermogravimetry (DTG), and differential scanning calorimetry (DSC). The results revealed that increasing SiO2 content has improved some critical thermal parameters, including onset, midpoint, inflection, and end temperatures. At 1.00 wt% SiO2, the onset temperature of the biolubricant increased by 23.70 °C, reaching 345.30 ± 0.64 °C, while that of the lubricant increased by 24.55 °C, reaching 297.5 ± 1.84 °C. Maximum oxidation induction times of 29.65 ± 3.18 min (biolubricants) and 27.70 ± 1.04 min (lubricants), along with enthalpy values of 509.45 ± 26.8 J·g−1 and 459.85 ± 12.66 J·g−1, respectively, were achieved at the same concentration. These findings demonstrate that surface-modified SiO2 nanoparticles significantly enhance the thermal stability and oxidation resistance of both conventional and bio-based lubricants, highlighting nanoparticles’ potential to improve engine performance, extend possible industrial applications, and theoretically extend oil-change intervals, with obvious environmental and economic benefits.