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Natural Oils as Lubricants
Published in Leslie R. Rudnick, Synthetics, Mineral Oils, and Bio-Based Lubricants, 2020
Joseph M. Perez, Leslie R. Rudnick, Sevim Z. Erhan, Brajendra K. Sharma, Kirtika Kohli
Viscosity index is a measure of the rate of change of the viscosity of a fluid with temperature. The higher the number, the better the VI is. Vegetable oils have an exceptional high viscosity index, typically over 200 compared to 80–120 for mineral oils. However, the viscosity of most vegetable oils containing mostly 16–18 carbon atoms is similar, about 9–10 cSt at 100°C and 40–45 cSt at 40°C. This limits the lubricant applications unless the oils are blended with viscous synthetic polymers or thermally polymerized.
Lubrication and Wear
Published in Neville W. Sachs, Practical Plant Failure Analysis, 2019
Another important concept to understand with liquid lubricants is the viscosity index. All liquids change viscosity as the temperature changes and some vary much more than others. The viscosity index (VI) is an artificial measurement that can be used to understand those differences and Figure 8.7 shows three oils that have the same viscosity at 99°C (210°F) but different VIs.
Lubrication Systems
Published in Peter Lynwander, Gear Drive Systems, 2019
The viscosity index is a measure of how much the oil viscosity varies with temperature. It would be ideal if the fluid viscosity were the same at low and high temperatures, but this is unattainable. Fluids that have low viscosity variations with temperature have a high viscosity index, whereas a low viscosity index defines a fluid with a widely fluctuating viscosity with respect to temperature. Typical viscosity indexes for petroleum oils range from 90 to 110.
Preparation and physicochemical properties evaluation of epoxidized neem oil-based bio-lubricant
Published in Australian Journal of Mechanical Engineering, 2023
Mohammed Kareemullah, Asif Afzal, K. Fazlur Rehman, Vishwanath K C, Hurmathulla Khan, Manzoore Elahi. M. Soudagar, Abdul Razak Kaladgi
Viscosity index is the measure of change in viscosity of oil with increase in temperature. Higher the viscosity index of oil better is its resistance to change in viscosity with increase in temperature. From Figure 7 it can be observed that there was 0.73% increase in viscosity index of Neem oil after epoxidation. There was 23.6% increase in viscosity index after addition of 25% synthetic oil to epoxidized Neem oil. There was 19% increase in viscosity index after addition of 50% synthetic oil to epoxidized Neem oil. Mineral oil shows the lowest ability to retain the viscosity with increase in temperature. 25% blended synthetic oil has provided a significant resistance due to the reorientation of bonds and 50% blend shows that there exists an upper limit for improvement is the viscosity index beyond which it does not improve.
A composite ultrafiltration membrane for regeneration of used engine oil
Published in Energy Sources, Part A: Recovery, Utilization, and Environmental Effects, 2020
Fatemeh Rouzegari, Javad Sargolzaei, Navid Ramezanian
The viscosity index of the regenerated oil reached 147 when using PGF composite membrane. In the filtration with the PGF membrane was more prominent than with the PVDF membrane. Higher viscosity index makes viscosity more stable and desirable in a across range of temperatures. As well, in Table 2, the results obtained on the flash point of the permeated oil were 212°C and 220°C from the PVDF and the PGF membranes, respectively. The results showed that the re-refined oil possessed good flash point that could be still used. The difference between the flash point of the fresh oil and that of the permeated oil could be traced to the breakdown of the light ends following the oxidation process and the high temperature of the used lubricant during usage. In addition, the specific gravity of the UEO also increased with the presence of growing aromatic compounds and amounts of solids. Their removal through UF membrane process could correspondingly reduce density. The results associated with the specific gravity for the used and the filtrated oils through the PVDF membrane and the PGF composite membrane shown appropriate reduction. The TAN for oils obtained by the UF membrane process were comparable with that of fresh oil. The values of the color code were further determined by 4.5–5. The filtrated oil was also observed with a dark color although it was visually clear.
Tribological Improvement Using Ionic Liquids as Additives in Synthetic and Bio-Based Lubricants for Steel–Steel Contacts
Published in Tribology Transactions, 2020
A. Z. Syahir, N. W. M. Zulkifli, H. H. Masjuki, M. A. Kalam, M. H. Harith, M. N. A. M. Yusoff, Z. M. Zulfattah, M. Jamshaid
Table 2 shows the physical properties of various blends. It can be observed that the addition of ILs did not alter the properties much in terms of viscosity and density in comparison to neat base oils (PAO8 and TMPTO). This is due to the small amount of ILs added to the base oils, thus resulting in a minimal effect on viscosity and density. Nevertheless, it can be observed in general that the kinematic viscosity of all blended base oils increased steadily with increasing concentrations of ILs due to the highly viscous nature of ILs. The highest viscosity of PAO8 and TMPTO blends (46.55 and 50.35 cSt, respectively) was observed when 1.5 wt% of IL1 was added. From Table 2, it can be observed that IL1 had the highest viscosity among the three tested ILs. The viscosity index (VI) of a lubricant indicates the effect of temperature deviation on viscosity. From Table 2, it can be observed that TMPTO and its blends exhibited higher VI compared to PAO8 blends. The higher VI of bio-based lubricants is due to the presence of fatty acid chain components, resulting in higher overall molecular weight (Salimon, et al. (37)).