Tribology and Materials | Volume 5 | Issue 2 | 2026 | 81-93
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https://doi.org/10.46793/tribomat.2026.008
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Thermal conductivity and viscosity of surfactant-stabilised biolubricants containing TiO2 and BN nanoparticles
Yathish Kumar
1,
Binu Kottoor Gopalakrishna
1,
Ravikantha Prabhu1,
Sharun Mendonca1,
Rolvin Dsilva1,
Ravindra Mallya2,
Girish Hariharan2
1 St Joseph Engineering College, Mangaluru, India
2 Manipal Institute of Technology, Manipal, India
Abstract: This study examines how adding titanium dioxide (TiO2) and boron nitride (BN) nanoparticles to Jatropha-based biolubricant improves its viscosity and thermal conductivity. The impact of sonication time, concentration of surfactant (oleic acid), nanoparticle type and nanoparticle content on the thermal and rheological behaviour of the biolubricants was assessed. To guarantee homogeneous dispersion, biolubricants containing 0.05 – 0.20 wt. % TiO2 or BN were made using ultrasonic agitation. To determine the importance of the parameters and their interactions, a statistical analysis of thermal conductivity and viscosity was conducted. Because of its higher heat transfer properties and dispersion stability, BN consistently produced significant improvements in the biolubricant's thermal performance when nanoparticles were added. The highest thermal conductivity of 0.262 W/mK was obtained at 0.20 wt. % BN nanoparticle content and a 10X surfactant concentration, while viscosity remained within acceptable limits for lubrication applications. The type of nanoparticle emerged as the most significant factor, followed by nanoparticle content, for both thermal conductivity and viscosity. Overall, the results indicate that optimising formulation parameters can significantly improve heat transfer performance without compromising flow behaviour. Biolubricants filled with BN and TiO2, therefore, show strong potential as environmentally sustainable lubricants for thermal management and industrial applications.
Keywords: biolubricants, thermal conductivity, boron nitride, titanium dioxide, surfactant concentration, nanofluid optimisation.
Received: 05-11-2025, Revised: 21-02-2026, Accepted: 20-03-2026
This work is licensed under a Creative Commons Attribution-NonCommercial 4.0 International (CC BY-NC 4.0) license, which allows users to distribute, remix, adapt,
and build upon the material in any medium or format for non-commercial purposes only, and only so long as attribution is given to the creator.
2 Manipal Institute of Technology, Manipal, India
Abstract: This study examines how adding titanium dioxide (TiO2) and boron nitride (BN) nanoparticles to Jatropha-based biolubricant improves its viscosity and thermal conductivity. The impact of sonication time, concentration of surfactant (oleic acid), nanoparticle type and nanoparticle content on the thermal and rheological behaviour of the biolubricants was assessed. To guarantee homogeneous dispersion, biolubricants containing 0.05 – 0.20 wt. % TiO2 or BN were made using ultrasonic agitation. To determine the importance of the parameters and their interactions, a statistical analysis of thermal conductivity and viscosity was conducted. Because of its higher heat transfer properties and dispersion stability, BN consistently produced significant improvements in the biolubricant's thermal performance when nanoparticles were added. The highest thermal conductivity of 0.262 W/mK was obtained at 0.20 wt. % BN nanoparticle content and a 10X surfactant concentration, while viscosity remained within acceptable limits for lubrication applications. The type of nanoparticle emerged as the most significant factor, followed by nanoparticle content, for both thermal conductivity and viscosity. Overall, the results indicate that optimising formulation parameters can significantly improve heat transfer performance without compromising flow behaviour. Biolubricants filled with BN and TiO2, therefore, show strong potential as environmentally sustainable lubricants for thermal management and industrial applications.
Keywords: biolubricants, thermal conductivity, boron nitride, titanium dioxide, surfactant concentration, nanofluid optimisation.
Received: 05-11-2025, Revised: 21-02-2026, Accepted: 20-03-2026
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This work is licensed under a Creative Commons Attribution-NonCommercial 4.0 International (CC BY-NC 4.0) license, which allows users to distribute, remix, adapt, and build upon the material in any medium or format for non-commercial purposes only, and only so long as attribution is given to the creator.