scholarly journals Low-Temperature Rheology and Thermoanalytical Investigation of Lubricating Greases: Influence of Thickener Type and Concentration on Melting, Crystallization and Glass Transition

Lubricants ◽  
2021 ◽  
Vol 10 (1) ◽  
pp. 1
Author(s):  
Andreas Conrad ◽  
Annika Hodapp ◽  
Bernhard Hochstein ◽  
Norbert Willenbacher ◽  
Karl-Heinz Jacob
Keyword(s):  
Glass Transition ◽  
Propylene Glycol ◽  
Crystallization Temperature ◽  
Sharp Increase ◽  
Pour Point ◽  
Mineral Oil ◽  
Base Oil ◽  
Alkyl Chains ◽  
Base Oils ◽  
Crystallization Nucleus

This study investigates crystallization, melting and glass transition of Li- and Ca-12-hydroxystearate greases in relation to the pour point of the corresponding oils. The base oils for the greases are mineral oil, polyalphaolefin, alkylated naphthalene, propylene glycol, and trimellitate. For the mineral oil-based greases the crystallization temperature Tc increases and the melting temperature Tm decreases upon addition of thickener. The pour point of the mineral oil then is 3 K below Tc and does not properly define the lowest application temperature for mineral oil (MO) based greases. Both thickeners induce a small increase of the glass transition temperature (1–3 K) of the synthetic oils polyalphaolefin, alkylated naphthalene, propylene glycol. The pour point of the base oils correlates well with the onset of the glass transition in the corresponding grease indicated by a sharp increase in grease viscosity. Pure trimellitate with unbranched alkyl chains does not crystallize upon cooling but shows noticeable supercooling and cold crystallization. As the percentage of thickener in corresponding greases increases, more oil crystallizes upon cooling 20 K above the crystallization temperature of the trimellitate without thickener (−44 °C). Here, the thickener changes the crystallization behavior from homogeneous to heterogeneous and thus acts as a crystallization nucleus. The pour point of the base oil does not provide information on the temperature below which the greases stiffen significantly due to crystallization.

scholarly journals Comparative Study on Mechanical Properties of Sealing Grease Composed of Different Base Oils for Shield Tunnel

Materials ◽  
2020 ◽  
Vol 13 (3) ◽  
pp. 692 ◽  
Author(s):  
Xiangqian Li ◽  
Yuyou Yang ◽  
Fan Li
Keyword(s):  
Mechanical Properties ◽  
Vegetable Oil ◽  
Exponential Function ◽  
Flow Rate ◽  
Temperature Sensitivity ◽  
Mineral Oil ◽  
Shield Tunnel ◽  
Fixed Temperature ◽  
Base Oil ◽  
Base Oils

This study proposes a novel sealing grease with improved mechanical properties and environmental performance. A series of sealing grease samples were made with different base oils, including mineral oil and renewable oil (vegetable oil and lard). In this study, thermogravimetric analysis (TGA) was conducted to study the adsorption capacity of the thickener to the base oil. The fluidity of the sealing grease was also tested at different temperatures. Furthermore, an exponential function was proposed for the flow rate of the sealing grease and the temperature. Moreover, a cone penetration test was conducted to study the consistency of the sealing grease. The results indicated that the capacity of the thickener to adsorb vegetable oil was greater than that of mineral oil, but less than that of lard. Additionally, the flow rate of the sealing grease increased with an increase in temperature. At a fixed temperature, the flow rate of the sealing grease increased with the base oil content. According to the exponential function, the composition of the base oil is the key factor that determines the temperature sensitivity of the sealing grease. In addition, the sealing grease made of vegetable oil has the minimum temperature sensitivity coefficient.

The study of the qualities of light and oil fractions of Azeri oil

2021 ◽  
Vol 02 ◽  
pp. 28-31
Author(s):  
G.S. Mukhtrova ◽  
◽  
Yu.A. Abdullayeva ◽  
R.Z. Hasanova ◽  
S.B. Logmanova ◽  
...  
Keyword(s):  
Sulfur Content ◽  
Pour Point ◽  
Viscosity Index ◽  
Antioxidant Properties ◽  
Hydrocarbon Composition ◽  
Base Oil ◽  
Base Oils ◽  
Oil Fraction ◽  
Oil Fractions ◽  
Light Oil

The article provides research on the qualities of Azeri oil and its light and oil fractions. A characteristic feature of Azeri oil is its high content of light fractions. This oil is light, low-sulfur, and paraffinic. Azeri oil in terms of density, sulfur content, content of light (light) fractions corresponds to marketing grades of oils and is called Azeri Light. Along with light fractions, Azeri Light oil contains up to 30-32% of oil fractions boiling above 350°C. Studies of 50°C oil fractions 350-500°C showed that the viscosity of the fractions at 100°C is in the range of 2.5-10.2 mm2/s, the viscosity index is 72-79.3, and the pour point is 12-36°С, potential content of base oils - 25.73%, their hydrocarbon composition, %: n-paraffinic oils - 50.7; isoparaffinic + naphthenic - 10.67; aromatic - 8.94%. Using traditional methods of purification using a selective solvent, followed by dewaxing and hydrotreating, from 50°C oil fractions of Azeri oil, base oils with a viscosity of 4.2-9.0 mm2/s at 100°C and a viscosity index of 91.0 can be obtained - 95.8, pour point minus 15°С / minus 20°С. By cleaning a wide oil fraction of 350-500°C, it is possible to obtain a base oil with a viscosity at 100 C of 6.5 mm2/s (SAE 20), a viscosity index of 95, a pour point of minus 15°C, an oil yield (350-500°C) is 20.3% for distillate (12.4% for oil). In terms of saturated hydrocarbons content (≥90%, sulfur content less than 0.03%), viscosity index > 90, the oil has good antioxidant properties and can be assigned to API group II.

Effect of Water on Electrical Properties of Refined, Bleached, and Deodorized Palm Oil (RBDPO) as Electrical Insulating Material

2013 ◽  
Vol 64 (4) ◽  
Author(s):  
Nazera Ismail ◽  
Yanuar Z. Arief ◽  
Zuraimy Adzis ◽  
Shakira A. Azli ◽  
Abdul Azim A. Jamil ◽  
...  
Keyword(s):  
Electrical Properties ◽  
Breakdown Voltage ◽  
Palm Oil ◽  
Pour Point ◽  
Electrical Breakdown ◽  
Dissipation Factor ◽  
Mineral Oil ◽  
Flash Point ◽  
Effect Of Water ◽  
Insulating Liquid

This paper describes the properties of refined, bleached, deodorized palm oil (RBDPO) as having the potential to be used as insulating liquid. There are several important properties such as electrical breakdown, dielectric dissipation factor, specific gravity, flash point, viscosity and pour point of RBDPO that was measured and compared to commercial mineral oil which is largely in current use as insulating liquid in power transformers. Experimental results of the electrical properties revealed that the average breakdown voltage of the RBDPO sample, without the addition of water at room temperature, is 13.368 kV. The result also revealed that due to effect of water, the breakdown voltage is lower than that of commercial mineral oil (Hyrax). However, the flash point and the pour point of RBDPO is very high compared to mineral oil thus giving it advantageous possibility to be used safely as insulating liquid. The results showed that RBDPO is greatly influenced by water, causing the breakdown voltage to decrease and the dissipation factor to increase; this is attributable to the high amounts of dissolved water.

Study on the Safety of Mineral and Synthetic Oil Added Commonly Used Extreme Pressure Additives

2012 ◽  
Vol 430-432 ◽  
pp. 1386-1389
Author(s):  
Zhuo Jun Chen ◽  
Long Long Feng ◽  
Bao Liang Li ◽  
Jin Jin Yue ◽  
Ying Liang Wu ◽  
...  
Keyword(s):  
Acute Toxicity ◽  
Toxicity Test ◽  
Mineral Oil ◽  
Stimulation Test ◽  
Toxicity Tests ◽  
Acute Toxicity Test ◽  
Base Oil ◽  
Synthetic Oil ◽  
Four Levels ◽  
Oral Acute Toxicity

This article use the Sulphide Isobutene (T321), Five Sufides Dialkyl(RC2540) and Star of Phosphorus(P110) as the additives,Neopentyl Polyol Ester(NPE) and mineral oil N32 as base oil. Compound above additives and base oil for the four levels. A sample: adding 4% T321 additive in NPE. B sample: adding 4% T321 additive in N32. C sample: adding 4% RC2540 additive in NPE. D sample: adding RC2540, T321 and P110 additives in NPE (all is mass fraction). The oral acute toxicity test, eye mucous stimulation test, skin hypersensitive test, soaking tail toxicity tests were conducted in above samples. The test results show that. The mineral oil, it’s not only toxic then synthetic oil but also has a poor lubricating ability compare with the same percent additive in synthetic oil. In oral acute toxicity test, eye mucous stimulation test, skin hypersensitive test, soaking tail toxicity tests, Toxic reaction of mineral N32+4%wt Sulphide Isobutene (T321) obviously from other oil samples.

Kinetic Study of the Thermo-Oxidative Degradation of Squalane (C30H62) Modelling the Base Oil of Engine Lubricants

2009 ◽  
Author(s):  
Moussa Diaby ◽  
Michel Sablier ◽  
Anthony Le Negrate ◽  
Mehdi El Fassi
Keyword(s):  
Oxidative Degradation ◽  
Engine Oil ◽  
Ongoing Research ◽  
Base Oil ◽  
Rate Law ◽  
Tert Butyl ◽  
Oxidation Rates ◽  
Base Oils ◽  
Wide Range ◽  
Thermo Oxidative Degradation

On the basis of ongoing research conducted on the clarification of processes responsible for lubricant degradation in the environment of piston grooves in EGR diesel engines, an experimental investigation was aimed to develop a kinetic model which can be used for the prediction of lubricant oxidative degradation correlated to endurance test conducted on engines. Knowing that base oils are a complex blend of paraffins and naphtenes with a wide range of sizes and structures, their chemistry analysis during the oxidation process can be highly convoluted. In the present work, investigations were carried out with the squalane (C30H62) chosen for its physical and chemical similarities with the lubricant base oils used during the investigations. Thermo-oxidative degradation of this hydrocarbon was conducted at atmospheric pressure in a tubular furnace, while varying temperature and duration of the tests in order to establish an oxidation reaction rate law. The same experimental procedures was applied to squalane doped with two different phenolic antioxidants usually present in engine oil composition: 2,6-di-tert-butyl-4-methylphenol (BHT), and octadecyl-3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate (OBHP). Thus, the effect of both antioxidants on the oxidation rate law was investigated. Data analysis of the oxidized samples (FTIR spectroscopy, gas chromatography/mass spectrometry GC/MS) allowed to rationalize the thermo-oxidative degradation of squalane. The resulting kinetic modelling provides a practical analytical tool to follow the thermal degradation processes, which can be used for prediction of base oil hydrocarbon ageing. If experiments confirmed the role of phenolic additives as an affective agent to lower oxidation rates, the main results lay in the observation of a threshold temperature where a reversed activity of these additives was observed.

scholarly journals The Investigation of Viscometric Properties of the Most Reputable Types of Viscosity Index Improvers in Different Lubricant Base Oils: API Groups I, II, and III

Lubricants ◽  
2022 ◽  
Vol 10 (1) ◽  
pp. 6
Author(s):  
Seyed Ali Khalafvandi ◽  
Muhammad Ali Pazokian ◽  
Ehsan Fathollahi
Keyword(s):  
Viscosity Index ◽  
Behavioral Differences ◽  
Base Oil ◽  
Polymer Molecules ◽  
Base Oils ◽  
Two Temperatures ◽  
Higher Temperature ◽  
Viscosity Index Improvers ◽  
Lower Temperature ◽  
Definition Of

Four commercial viscosity index improvers (VII) have been used to investigate the behavioral differences of these compounds in three types of universally applicable base oils. The used VIIs are structurally three types of co-polymer: ethylene-propylene, star isoprene, and two di-block styrene-isoprene. After dissolving of different amounts of VIIs in different base oils, the kinematic viscosities at two standard temperatures were determined and the intrinsic viscosities were calculated according to Huggins method, then the effects of changes in base oil and polymer type were investigated. Intrinsic viscosities as criteria for polymer molecules sizes were found to be higher at lower temperature than at higher temperature. Dependence of intrinsic viscosity on the polymer molecular weight was observed. In the previous works, one or two types of VIIs were studied in only one type of base oil and/or solvent, not different base oils. Furthermore, different ranges of temperatures and concentrations not necessarily applied ranges were selected, but in this work, common base oils and most commercial VIIs were used and the viscometric properties were compared at two temperatures. Viscosities at these temperatures are used for determining VI and definition of lubricant’s viscosity grades. VI improvement is the main cause of VII usage.

Study on the Crystallization Activation Energy of Poly (L-lactic acid) Nucleated with P-tert-butylcalix[8]arene

2018 ◽  
Vol 26 (2) ◽  
pp. 169-175
Author(s):  
Yaoqi Shi ◽  
Liang Wen ◽  
Zhong Xin
Keyword(s):  
Activation Energy ◽  
Lactic Acid ◽  
Glass Transition ◽  
Transition Temperature ◽  
Glass Transition Temperature ◽  
Crystallization Temperature ◽  
Nucleating Agent ◽  
Crystallization Activation Energy ◽  
Temperature Range ◽  
Chain Mobility

The crystallization activation energy (Δ E) of a polymer comprises the nucleation activation energy Δ F and the transport activation energy Δ E*. In this paper, the Δ E of poly (L-lactic acid) (PLLA) nucleated with nucleating agent p- tert-butylcalix[8]arene (tBC8) was calculated. The results showed that the Δ E of nucleated PLLA was 165.97 kJ/mol, which is higher than that of pure PLLA. The reason why Δ E of PLLA increased when incorporating nucleating agent was studied. The increment of glass transition temperature ( Tg) for nucleated PLLA revealed that the polymer chain mobility was restricted by tBC8, which was considered as the reason for the increase of Δ E*. Further, polyethylene glycol (PEG) was added to improve the chain mobility, thus eliminated the variation of the transport activation energy Δ E* caused by tBC8. Then the effect of the increment of crystallization temperature range on the increase of Δ F was also taken into consideration. It was concluded that both decreasing the mobility of chain segments and increasing the crystallization temperature range caused an increase of Δ E for PLLA/tBC8.

scholarly journals Tribological behavior of oils additised with a phosphonium-derived ionic liquid compared to a commercial oil

2020 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Marlene Bartolomé Sáez ◽  
Antolin E. Hernández Battez ◽  
Jorge Espina Casado ◽  
José L. Viesca Rodríguez ◽  
Alfonso Fernández-González ◽  
...  
Keyword(s):  
Ionic Liquid ◽  
Peer Review ◽  
Formation Rate ◽  
Antiwear Additives ◽  
Stribeck Curve ◽  
Content Type ◽  
Base Oil ◽  
Base Oils ◽  
Antiwear Properties ◽  
Commercial Oil

Purpose The purpose of this paper is to study the antifriction, antiwear and tribolayer formation properties of the trihexyltetradecylphosphonium bis(2,4,4-trimethylpentyl) phosphinate ionic liquid (IL) as additive at 1 wt.% in two base oils and their mixtures, comparing the results with those of a commercial oil. Design/methodology/approach The mixture of the base oils used in the formulation of the commercial oil SAE 0W20 plus the IL was tested under rolling/sliding and reciprocating conditions to determine the so-called Stribeck curve, the tribolayer formation and the antifriction and antiwear behaviors. Findings The use of this IL as additive in these oils does not change their viscosity; improves the antifriction and antiwear properties of the base oils, making equal or outperforming these properties of the SAE 0W20; and the thickness and formation rate of the tribolayer resulting from the IL-surface interaction is highly dependent on the type of base oil and influence on the friction and wear results. Originality/value The use of this IL allows to replace partial or totally commercial antifriction and antiwear additives. Peer review The peer review history for this article is available at: https://publons.com/publon/10.1108/ILT-05-2020-0179/

Improving the Performance of Gas Engine Oils: A New Generation of Geo-Specific Additive Systems

2003 ◽  
Author(s):  
Laurent Chambard ◽  
John Smythe
Keyword(s):  
High Performance ◽  
Additive Technologies ◽  
Performance Limits ◽  
Base Oil ◽  
Gas Engine ◽  
Engine Oils ◽  
Base Oils ◽  
Beaten Track ◽  
Excellent Control ◽  
New Generation

Additive technologies able to successfully lubricate gas engines have been available for many years, but in recent years the acceleration of both commercial and technical demands placed on gas engine lubricants has highlighted the performance limits of traditional additive solutions. One of these limits is the ability to reach long and very long oil drains, required by an increasing number of operators. Since traditional additive chemistries on conventional base oil systems have reached their limits in that respect, focus has been increasingly placed on using higher performance base oils so that longer oil drains can be reached. However, traditional additive chemistries have often proved to struggle in these higher performance base oils, particularly in the aspect of deposit control — demonstrating that a new generation of additive systems for the formulation of gas engine oils is needed. The authors present one such generation of additive systems, developed around off-the-beaten-track detergent technology; providing superior control of oxidation and deposits. Such additive systems can be used either in conventional base oil systems with improved drain interval, or in high performance base oil systems with very long drain interval and excellent control of deposits. Besides the description of the chemistry involved, the authors also present a methodology of performance evaluation in the laboratory, and compare this methodology with the performance perceived in the field.

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