Effects of modified graphene in high oleic palm oil based methyl ester on friction and wear reduction
This research mainly focuses on the tribological properties of modified graphene in vegetable oil to reduce friction and wear in journal bearing applications. Journal bearings are prone to severe friction and wear effects due to uneven shaft speeds, which affect the performance of the journal bearin...
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| Format: | Thesis |
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2023
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| Summary: | This research mainly focuses on the tribological properties of modified graphene in vegetable oil to reduce friction and wear in journal bearing applications. Journal bearings are prone to severe friction and wear effects due to uneven shaft speeds, which affect the performance of the journal bearing and its service life. Apart from this, the depletion of mineral oils and environmental concerns have led this research project to propose a new nanofluid lubricant with graphene as a nanoparticle additive and vegetable oil as the base oil. Graphene nanoplatelets (GNP) are chemically surface-modified with sodium dodecyl sulfate (SDS) and oleic acid (OA) to improve their dispersion stability in the base oil fluid, high oleic palm oil based methyl ester (high oleic POME), by increasing their hydrophobicity. The SDS solution is first mixed with the GNP so that the SDS molecules adhere to the GNP surface and the sodium ions (Na+) are exposed in the external environment. After the addition of OA to the mixture, the hydroxyl group (OH-) of OA combines with the Na+ ion of SDS, so that the hydrophobic hydrocarbon chains of OA are exposed to the external environment, resulting in GNPs with better hydrophobicity. The modified GNPs are then used to synthesize modified GNP-oil nanofluids (mGON) at concentrations of 0.05, 0.06, 0.07, 0.08 and 0.09 wt%, while GNP-oil nanofluids (GON) are synthesized at concentrations of 0.02, 0.04, 0.06, 0.08 and 0.10 wt%. The objectives of this work are to study the friction and wear of contact pairs using a pin-on-ring tribo-tester exposed to mGON at different concentrations, and to investigate the thermophysical properties of mGON at different concentrations, including dynamic viscosity and thermal conductivity, which are compared with high oleic POME and GON samples. |
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