bluuebunny/crossref_metadata_2025 huggingface dataset:
Testing, application, and future development of environmentally friendly ester base fluids
Authors: van der Waal G. , Kenbeek D.
Published: July 2006

Biodegradation test methods have been compared with regard to test conditions and test parameters. It has been shown that three methods are, in principle, suitable for non‐water soluble products. These are the Sturm test (OECD no. 301B), the MITI test (OECD 301 C), and the CEC L‐33‐T‐82 test method. A comparison in an actual test showed that the CEC test gives the highest biodegradation values, while the Sturm test and the MITI test give lower values. It is noted that the CEC test measures the amount of material used for both energy production and growth of the biomass, while the other methods measure only the material used for energy production. A possible explanation for the difference between the Sturm and the MITI test results is given. The CEC test is shown to be more suitable for the lubricant industry. Applications of biodegradable lubricants are reviewed, particularly hydraulic fluids. It is shown that rape seed oil (natural ester) and synthetic polyol esters have similarities regarding structure but also significant differences. This results in much better thermal and oxidative stability for the synthetic esters. These also offer the possibility of making a range of products of different ISO grades with similar properties.

Brief consideration is given to future potential, notably for biodegradable four‐stroke lubricants. Finally, there is a timely reminder that, owing to the present limited availability of natural oils and fats and their cost, only 19% of the market for mineral oil base fluids could be replaced by natural oils and fats and their derivatives.
Magnetic fluids in sealing and lubrication – a state of the art review
Authors: Säynätjoki M. , Holmberg K.
Published: July 2006

The paper is a review of the properties and functions of magnetic fluids and their potential use in tribological applications, such as seals and bearings. They offer new possibilities for achieving low friction, low wear, and no leak‐ age.

Magnetic fluids or ferrofluids consist of magnetic particles suspended in a carrier fluid and a coating on the particles. The coating prevents the agglomeration of the particles through magnetic and molecular attraction by keeping the distance between them sufficiently large. The magnetic fluids have the basic properties of liquids and they act like ferromagnetic materials in the presence of an external magnetic field.

Shaft sealing is the most promising potential application for ferrofluids. Magnetic seals have zero‐leakage and low friction, they are non‐stick and they have high‐performance properties. Lubrication is another important application of ferrofluids. The advantage over conventional lubricants is the possibility of keeping the lubricant exactly and only where it is needed. They provide the possibility of increasing the life of components. Furthermore, because they do not contaminate, ferrofluids are also used as lubricants in clean environments.
A polyalphaolefin with exceptional low‐temperature properties
Authors: Theriot K. J. , Shubki R. L.
Published: July 2006

A new process has been discovered for the production of low‐viscosity PAO fluids in high yield. In particular, the new process can be used to produce a mixture of decene dimers that has low‐temperature properties which are superior to the properties of decene dimers produced by the conventional PAO process.
Soluble additives for perfluorinated lubricants
Authors: Srinivasan P. , Corti C. , Montagna L. , Savelli P.
Published: July 2006

High‐performance aerospace systems make severe demands on lubricants. Among the potential candidates, perfluorinated fluids, especially perfluoropolyethers (PFPEs), lead the list. PFPEs are unique in that several of the properties required for the lubrication of these systems, such as thermalloxidation stability, chemical inertness, compatibility with materials of construction, high viscosity index, etc., are inherent to them. However, there is a need to add other characteristics or to improve some of the inherent properties. Research programme to find a solution by preparing PFPEs with different structures as well as developing soluble anticorrosion, antiwear, and stabilising additives has been undertaken. The present paper describes the preliminary results obtained with a few additives and suggests possible action mechanisms.
Effect of testing conditions on friction and wear of a polyetheretherketone‐based composite
Authors: Guo Qiang , Friedrich Klaus
Published: July 2006

Friction and wear characteristics of a type of polyetheretherketone (PEEK)‐ based composite were evaluated under two different loading pressures and sliding speeds (P = 1.0 MPa, V = 1.0 m/s and P=2.0 Mpa, V=3.3 m/s). The material was in contact with steel surfaces of two different roughnesses (Ra=0.15 μm and Ra=0.33 μm). Interface temperature, coefficient offriction, depth wear rate, and specific wear rate of the polymer composite changed considerably with the PV value and the counterface roughness. The interface temperature increased with increasing PV value, whereas the friction coefficient decreased. The depth wear rate at the higher PV value was much higher than that at lower PV. In addition, the rougher counterface resulted in a higher friction coefficient, depth wear rate, and specific wear rate, when the PV value was fixed. The effect of counterface roughness on the specific wear rate at the higher PV value was smaller than that at the lower PV. Further variations in friction and wear with testing conditions are discussed along with the corresponding microscopic observations of the worn polymer surfaces and the polymer transferred counterfaces.
Use of a non‐conventional synthetic basestock in the formulation of high‐quality engine oils
Authors: Fisicaro G. , Fattori S.
Published: July 2006

Research has been undertaken to identify new synthetic basestocks, to be used alone or with polyalphaolefins, for the formulation of high‐quality engine oils.

Basestock selection was limited to products not normally used in the synthesis of ester‐type basestocks. A non‐conventional product was identified: a carbonic ester of synthetic alcohols. A complete engine oil has been formulated using this basestock and submitted to a full test programme. The results are reported.
Low pour point polyalkyl benzene oils for refrigeration compressors
Authors: Cvengroš Ján , Faberová Anna , Lazar Ľubomír
Published: July 2006

In this paper, the results of fractionation of polyalkyl benzene residues from monoalkyl benzene production, using a molecular evaporator to obtain fractions which are usable as lubrication oils for refrigeration compressors with a non‐polar refrigerant, are presented. Two of the distillion fractions pre‐pared correspond to international viscosity classes I S 0 VG 22 and 46. Their yields of 45 and 15% respectively from the original residues are economically interesting and they are of a higher quality than the previously used mineral oil based lubricants. The polyalkyl benzenes have improved properties, such as viscosity index, flash point temperature, and pour point. The lower thermo‐oxidative stability of the fractions is compensated for formulations with appropriate antioxidants.
Synthetic fluids between synthetic hydrocarbons and ester fluids: Co‐oligomers of alphaolefins and alkylmethacrylates
Authors: Jelitte Rüdiger , Beyer Claudia
Published: July 2006

Through co‐oligomerisation of alphaolefins with alkylmethacrylates, fluids are obtained with a unique chemical combination of non‐polar PAO and polar ester oil in one molecule. The polarity of these co‐oligomers between P A 0 on the one hand and ester oil on the other helps to avoid the typical disadvantages of these common synthetic base oils. Thus, co‐oligomers offer superior solvency for DI packages, neutral elastomer behaviour, the hydrolytic stability of sterically hindered esters, a thermal and oxidative stability close to PAO, and free miscibility with mineral oil and synthetic base stocks. Co‐oligomers are Newtonian fluids of high purity and with a viscosity range between 50 and 600 mm2/s at 100°C. Both viscosity level and purity open up a range of applications. Even without high molecular weight VI improver, gear oils, and hydraulic oils with outstanding viscometric performance can be formulated. The purity has a positive influence on properties such as demulsibility, de‐aeration, and foaming behaviour. The present paper compares co‐oligomers with common base fluids and gives examples of typical applications.
Tribological characteristics of Perfluoropolyether liquid lubricants under sliding conditions in high vacuum
Authors: Masuko Masabumi , Jones William R. , Helmick Larry S.
Published: July 2006

Tribological characteristics of three PFPEs (Fomblin Z, Demnum, and Krytox) were studied under high vacuum using a four‐ball apparatus with 440C steel specimens. Fomblin Z and Demnum exhibited initial scuffing‐like high friction whereas Krytox did not. Steady state friction with Fomblin Z was the lowest among the three oils and that with Demnum and Krytox was almost the same. The lowest wear rates in air were provided by Krytox regardless of load and low wear rates in vacuum at high load were achieved with Krytox and Demnum. Results are explained by reactivity and pressure‐viscosity characteristics of the oils.
Improvement of the wear behaviour of the couple UHMWPE–Ti6A14V through surface treatments
Authors: Martinella R. , Giovanardi S. , Palombarini Lg. , Giorgi R.
Published: July 2006

Owing to the great interest in the medical field in the tribological couple UHMWPE–Ti6Al4V, its wear behaviour was studied and compared to that displayed by the more typical couples of UHMWPE–AISI 316 and UHMWPE–Vitallium.

The Ti6Al4V alloy was given three different surface treatments: (a) a conventional lapping procedure; (b) a special lapping procedure; (c) nitrogen ion‐implantation at 873°K. The last two samples induced, on a UHMWPE countetace, a wear rate lower than a factor of 10 compared to diamond lapped specimens; their behaviour was also better than the couples UHMWPE–AISI and UHMWPE–Vitallium.

Wear improvement was attributed to the reduction of polymer transfer and adhesion on the metal counterface, due to the reduction of adhesive affinity between UHMWPE and the metal following surface treatment of the metal. The results are interpreted on the grounds of TEM and AES analyses.
Performance testing of lubricants based on high oleic vegetable oils
Authors: Lal Kasturi , Carrick Virginia
Published: July 2006

Owing to growing environmental concerns, vegetable oils are finding their way into lubricants for industrial and transportation applications. Vegetable oils can of Ser significant environmental advantages with respect to resource renewability and biodegradability, as well as offering satisfactory performance in a variety of applications. Synthetic ester‐based fluids may also offer these advantages, however their cost can be prohibitively high. Formulating with vegetable oil does, however, present unique challenges. These are, most notably, the oxidative and hydrolytic instability and low temperature problems associated with the triglyceride. However, through advanced plant breeding techniques, vegetable oils are becoming available which exhibit excellent thermal and oxidative stability and other improved performance properties. The cost of these oils is much lower than synthetic esters, thereby making them attractive ‘environmental’ base fluids.
Biodegradability and toxicity of polyalphaolefin base stocks
Authors: Carpenter Joel F.
Published: July 2006

Low viscosity polyalphaolefin fluids (2 and 4 cSt ® 100°C) are significantly biodegraded under the conditions of the CEC‐L‐33‐T‐82 test procedure. This is contrary to the widespread, but inaccurate, perception that polyalphaolefin (PAO)fluids are generally not biodegradable. In a time‐extended CEC‐L‐33‐T‐82 test, the 2, 4, and 8 cSt fluids were shown to continue biodegrading well past the 21 ‐day span prescribed in the standard method. PAO fluids are considered non‐toxic and non‐irritating to mammals. Moreover, they are not expected to be toxic to aquatic organisms: in the Microtox® test with bioluminescent bacteria, no observable effects were detected for concentrations of 49,500 ppm of the water‐soluble fraction.
Thermo‐oxidative behaviour of perfluoropolyalkylethers
Authors: Koch B. , Jantzen E.
Published: July 2006

For high‐temperature aircraft turbine engines in the next century, new, extremely stable lubricants will be required. The chemical class known as perfluoropolyalkylethers is well known for its good and wide range of temperature behaviour. This paper reports on investigations into the thermo‐oxidative stability of these fluids at high temperatures. The work includes the influence of metals on the stability, and corrosion tests, of selected PFPAE oils. The results show the large influence of the chemical structure and of certain metals.
Die‐less wire drawing using polymer fluids
Authors: Symmons G. R. , Stokes M. R.
Published: July 2006

A die‐less wire drawing process has been developed in order to investigate the performance on the reduction of wire size of polymer coating on steel wire. Previous experimental investigations have shown significant reductions in area particularly using nylon and borosiloxane on copper wire. The present investigation shows that satisfactory reductions can also be obtained using these polymers on steel wire. A smooth adhered coating of the wire was produced with the nylon; however, drawing speed limitations were observed where break up of the coatings occurred.
The origins of synthetic lubricants: The work of Hermann Zorn in Germany part 2 esters and additives for synthetic lubricants
Authors: Jantzen Eilhard
Published: July 2006

The second part of this survey of the work of Hermann Zorn1 covers his research work on esters, and their introduction as lubricants into aviation and other applications. The additives developed for these applications are also described.
Biodegradable lubricants — Analysis of metalworking oils and hydraulic fluids by mass spectroscopy
Authors: Zeman Alfred
Published: July 2006

Biodegradable metalworking oils and hydraulic fluids were screened for their base oil composition using a special mass spectrometric technique — direct exposure probe chemical ionisation mass spectrometry (CI(NH3)‐MS). All but one of the hydraulic fluid samples were rapeseed oil or trimethylolpropane trioleate based, the other sample being a neopentylglycol ester trimethylolpropane ester mixture. Ethylhexyl ester of rapeseed oil fatty acids (or similar) was present in some of the metalworking fluids in addition to rapeseed oil, whilst other samples were pure rapeseed oil. In several cases a trimethylolpropane/neopentylglycol ester base was found. Preliminary results for additive isolation/identification show the usefulness of preparative gel permeation chromatography.
Evaluation of potassium trifluoroacetylacetonate as a synergist for arylamine antioxidant in synthetic lubricants
Authors: Yao Junbin , Dong Junxiu
Published: July 2006

Differential scanning calorimetry (DSC) was employed to evaluate the performance of an ester lubricant containing potassium trifluoroacetylacetonate. In the isothermal DSC oxidation test, potassium trifluoroacetylacetonate is an effective synergist for arylamine antioxidants such as p, p'‐dioctyldiphenylamine (DODPA). In combining with arylamine antioxidants, potassium trifluoroacetylacetonate can also effectively reduce the increase in viscosity and acid number of the ester oil in oxidation‐corrosion tests. The electron paramagnetic resonance (EPR) results indicated that potassium trifluoroacetylacetonate can reduce the free radical content in the oxidised oil when arylamine antioxidants are present.
Sulphurised vegetable oils as EP additives for industrial gear oil formulations
Authors: Bisht R. P. S. , Bhatia V. K.
Published: July 2006

Renewable sources can provide, besides fuel, a wide range of feed stocks for the organic chemicals industry. Utilisation of non‐edible vegetable oils and speciality chemicals has, therefore, become relevant in recent times. Sulphurisation of three triglyceride oils (karanja, rapeseed, and castor oils) and liquid wax (jojoba) has been investigated in detail in order to examine the potential of sulphurised vegetable oils for use as extreme‐pressure (EP) additives for developing formulations for industrial gear oils. The capacity of these oils with respect to the uptake of sulphur, the limitations of some of the sulphurised products for use as EP additives, and the problems in developing such formulations for industrial gear oils, are discussed.
Development of ecologically responsive lubricants
Authors: Adamczewska J. Z. , Wilson D.
Published: July 2006

As a result of growing environmental concerns, vegetable oils are finding their way into lubricants for both industrial and transportation applications. These oils can offer significant environmental advantages with respect to resource renewability and biodegradability, as well as offering satisfactory performance in various applications. Formulating with vegetable oils does, however, present unique challenges. These are, most notably, the oxidative and hydrolytic instability, and low temperature rheological problems associated with triglycerides. However, through advanced plant breeding techniques, vegetable oils are becoming available which exhibit good thermal and oxidative stability and other improved performance properties. An overview comparing the physical and chemical characteristics of vegetable oils with those of mineral oils, with particular emphasis on their oxidative stability and wear performance, is presented. Development of lubricant formulations for, in particular, farm tractors and hydraulic fluids, using combinations of vegetable oils and additives, will be discussed in comparison with field trial data.
The optical EHD method applied to the study of ageing of biodegradable oils
Authors: Cloesen C. , Kabuya A. , Bozet J. L.
Published: July 2006

In the present study, modifications of the lubricating properties of vegetable oils, which had undergone accelerated ageing, were quantified, using the optical EHD method. Each oil sample was examined in an optical viscometer in order to measure film thickness vs. contact speed. From these results the pressure—viscosity coefficient was calculated, by adjusting theoretical values. The modifications were related to molecular changes, which were observed with various tools of chemical analysis, including gel permeation chromatography (GPC).
Determination of spontaneous ignition temperatures of ester‐based aviation lubricants using pressure differential scanning calorimetry (PDSC)
Authors: Basken A. , Zeman A. , Maier K.
Published: July 2006

The usefulness of pressure differential scanning calorimetry (PDSC) in the determination of spontaneous ignition temperatures (SITs) of newly developed ester‐based aviation turbine engine oils is shown. Data on the reproducibility of measurements on aluminium and steel surfaces is given.
Lubricant components from vegetable oils of indian origin
Authors: Anand O. N. , Mehta J. , Prasada T. S. R. Rao
Published: July 2006

A number of transesterified and alkarylated derivatives have been synthesised from available vegetable oils of Indian origin. The viscosity, viscosity index, freezing points, load‐carrying characteristics, friction coefficient, and thermo‐oxidative stability of these derivatives as compared to highly refined hydrorefined hydrocarbon oils have been studied.

It has been found that several esters of fatty acids of these vegetable oils have a high natural viscosity index, low pour points, and high thermooxidative stability, and can meet the requirements as base fluid components for energy‐efficient, eco‐friendly, long‐drain interval, multigrade oils. These oils have markedly lower viscosities at 40°C, higher load‐carrying characteristics, and lower friction coefficients than the base fluids of currently marketed multigrade oils. A 50% blend with hydrorefined hydrocarbon oils could prove highly viable.

The above results clearly establish the potential for utilising these esters, either alone, or in combination with mineral oils, for formulating cost‐effective high‐performance, energy‐efficient, and environmentally friendly lubricants. Performance characteristics of these oils as engine oils, automotive gear oils, and 2 stroke oil with conventional additives and with alternative additives are under investigation in comparison to the most advanced hydrocarbon based multigrade oil formulations of long‐drain interval.
Detailed characterisation of polyalphaolefins and their branched structures using multi‐pulse NMR techniques
Authors: Kapur G. S. , Sarpal A. S. , Sarin R. , Jain S. K. , Srivastava S. P. , Bhatnagar A. K.
Published: July 2006

The present work describes some structural investigations carried out on commercial and laboratory synthesised polyalphaolefin (PAO) samples. A number of structures having different branched groups along the chain have been identified in the hydrogenated dimer product of 1‐decene, using multi‐pulse 13C‐NMR DEPT techniques. These branched structures have been further confirmed by correlating methyl and methine group resonance in the 13C‐NMR spectra, using a CALMOD computer program. An insight into the molecular mobility and dynamics of various structures has been obtained through spin lattice relaxation measurement. The study aims to provide a better understanding of the structure—performance relationships in PAOs. A probable mechanism of oligomerisation responsible for the formation of the identified structures is proposed.
Functional fluids and additives based on vegetable oils and natural products: A review of the potential
Authors: Patil A. S. , Pattanshetti V. A. , Dwivedi M. C.
Published: July 2006

Functional fluids and additives normally have an ‘R — P’ type of linear chemical structure, where ‘R’ is a linear or isoalkyl chain, and ‘P’ is a mild‐to‐strong polar group. For functional fluids ‘P’ is non‐polar to mildly polar, and for additive molecules it is mild to highly polar. The additive activity depends upon the degree of polarity.

Some natural products also have predominantly linear structures in their constituents. Many of these are available in commercial quantities and some even occur as waste. These could be used for the synthesis of functional fluids and additives. This paper covers three groups of such natural products. These are non‐edible vegetable oils, terpenes, and cashew nut shell liquid. The synthesis and characteristics of functional fluids and a variety of possible additives are described. Besides being an alternative non‐petroleum resource, such products have a high degree of biodegradability, as they are derivatives of natural products.
Influence of load and lubricants on EHD film thickness and rolling‐contact fatigue lives of AISI 52100 steel balls
Authors: Fernández J. E. , Luque P. , Cuervo D. G.
Published: July 2006

This work has evaluated the influence of load and type of lubricant on the thickness of the elastohydrodynamic (EHD) film and the rolling‐contact fatigue lives of AISI 52100 steel balls. The lubricants studied have various viscosities and included two mineral oils and five synthetic oils from three families. Firstly, the central film thickness was determined in order to predict the lubrication regime. The stress—number of cycles fatigue curves were then calculated by means of Weibull plots, and the fatigue mechanism was evaluated.

The test machine used for the analysis was a Seta‐Shell 1980 four‐ball EP lubricant tester. The 12.7 mm diameter test balls were made from a single batch of carbon‐vacuum‐deoxidised AISI 52100 steel with hardness RC65.

Elastohydrodynamic film thickness estimation was carried out using pressure—viscosity coefficients (a). In this study, to calculate (X), a new interferometric technique, ultrathin film interferometry, was employed to measure the film thickness. A practical method was developed for evaluating EHD, mixed film, and solid lubrication processes. Micrographic mapping and energy dispersive spectroscopy (EDS) were used to analyse the rolling track of the test balls.
Accumulation of lead in ester‐based engine oils
Authors: Baumann W. , Reiter K. , Zeiner W.
Published: July 2006

Synthetic esters are widely used as base‐oil components in top‐tier crankcase lubricant formulations. In combination with synthetic hydrocarbons, an ester content of between 10 and 50 wt.% is common. Only a few engine oils with an ester content above 85 wt.% have been introduced on to the market as yet. The use of such engine oils is advantageous, especially in environmentally sensitive areas, in terms of volatility, particle emissions, and biodegradability.

Some older types of heavy‐duty diesel engine continue to be run in vehicles and in machinery in the construction industry, and in such engines a higher lead content has been detected when ester‐based engine oils have been used. It has been found that lead is extracted from the bearings and accumulates ultimately in the engine oil during operation. Consequently, the development of a suitable inhibitor system has been initiated to improve engine and bearing protection. To determine the effectiveness of the new inhibitors, a suitable test method had to be found.

Using a test method based on the Petter WI (CEC L‐02‐A‐78) test engine, the present paper summarises the results of tests on an inhibitor system to prevent lead extraction from bearings The metal contents reported in this paper were determined by ion conductive plasma atomic emission spectrometry.
Advances in US Air Force hydraulic fluids
Authors: Gschwender Lois J. , Snyder Carl E. , Sharma Shashi K. , Flanagan Stephanie R.
Published: July 2006

The US Air Force Wright Laboratory's Materials Directorate has been involved with the development and transition of advanced fluids and lubricants since the 1950s. The driving force for the development of new hydraulic fluids has primarily been and still is, improved fire resistance, although biodegradability and low toxicity have become increasingly important. This paper briefly traces the use of military aircraft hydraulic fluids from the beginning to the current state‐of‐the‐art.
Development of Al‐base lubricating grease thickeners
Authors: Dudás C. S. , Toth J. , Vuk A.
Published: July 2006

In this paper are presented the results of work on the development of poly‐oxo–aluminium acylates that are dissolved in synthetic lubricants, polyalphaolefins (PAOs) andpolyisobutenes (PIBs), and one pharmaceutical mineral oil in order to produce a range of greases that can be food‐grade, and have chemical stability.

The method of synthesis is described, together with the results using different base oils (two different PAOs, four different polybutenes, and a pharmaceutical grade IS0 VG 46 white mineral oil. These greases are characterised here in terms of their mechanical stability and physical properties. As well as being of food grade, these greases are also shown to be chemically stable.
Lubricating properties of rapeseed‐based oils
Authors: Arnšek A. , Vižintin J.
Published: July 2006

Three commercially available hydraulic/transmission lubricants based on rapeseed oil have been investigated for their lubricating properties. The coefficient of friction, scuffing‐load capacity, and pitting resistance were evaluated, and the results compared with a corresponding commercial mineral‐based oil.

The results showed in general a substantially lower coefficient of friction and better pitting resistance for rapeseed‐based oils than for the mineral oil. Scuffing load capacity was, with one exception, the same for all oils. As a result of lower shear stresses during contact, and a higher viscosity index, the temperatures in the gearbox were lower for the rapeseed oils tested than for the mineral oil. Insufficient antiwear behaviour at high loads was found to be a major drawback of these vegetable oils.
Producing multigrade lubricating greases from animal and vegetable fat by‐products
Authors: El‐Adly R. A.
Published: July 2006

This paper reports on some work concerned with the synthesis and characterisation of three lubricating greases based on animal bone fat, cottonseed soapstock, and a mixture of them both. The physico‐chemical properties of these fats were established and showed them to be good thickeners in the preparation of different types of greases. It was shown that the growth of the soap structure and grease consistency depend on the type of fat as well as on the viscosity of the lubricating oil in the grease formulation. The greases so synthesised were assessed in accordance with standard NLGI grades and Egyptian standards. Their rheological and thermal behaviour was studied, which revealed that the synthesised greases have significant yield stress at normal operating temperature and good flow properties. It was concluded that the above mentioned fat by‐products are suitable for producing greases.
Synthesis and testing of ester lubricants for use as R‐134a refrigerants
Authors: Gryglewicz S. , Beran E.
Published: July 2006

The aim of the present work was to produce inexpensive synthetic lubricants, compatible with R‐134a, using waste carboxylic acids as the starting point. After initial synthesisation of some candidate materials, the suitability of the synthesised products was first evaluated by their chemical and physical properties including thermostability. Two ester bases were selected for further testing — a pentaerythritol esterified with monocarboxylic acids, and a polyalkyleneglycol similarly esterified with monocarboxylic acids C4—C6. The oil bases selected were tested for their corrosion effect on metals. The pentaerythritol ester offered the most advantageous properties in these tests. The results of the laboratory tests have been corroborated by trials conducted on real refrigerating compressor systems. In addition, the synthesis of base oils by methyl ester transesterification in the presence of basic catalysts has been examined.
Synthesis and testing of some new antioxidant and anticorrosion additives with potential for use in turbine aviation oils
Authors: Hassan H. M. , Youssif M. M. , Khalil A. M. , Youssif E. H. E.
Published: July 2006

This paper reports on work by the authors to develop a series of heterocyclic compounds for use in turbine aviation oils as antioxidant and anticorrosion additives. First, the new compounds were synthesised, and twenty‐eight candidate additives were developed. These were tested for their antioxidant and anticorrosion properties, and from these results three were found to exhibit better behaviour than the others. These three were then tested against DODPA, an existing aviation fluid additive, and were found to offer comparable behaviour in initial tests.
Environmentally adapted lubricants, Part I. An overview
Authors: Pal Mahendra , Singhal Sudhir
Published: July 2006

The requirement for environmentally adapted lubricants has begun to play an increasingly important role in many industrial applications, particularly in the last two decades. The present‐day requirements for biodegradable and eco‐friendly lubricants imply that lubricants have properties that can minimise, if not eliminate, negative environmental impact, such as contamination of soil and water, caused by lost lubrication, leakage and accidents. The dominant factors that have a direct impact on the environment and which characterise the lubricant and its chemical composition, are toxicity, bio‐accumulation and biodegradability. Biodegradability is perhaps the most important factor which determines the fate of lubricant in the environment.

Various commercial, governmental, and regulatory initiatives exist that protect the interests of the consumer. Life cycle analysis can help in assessing the total environmental impact of lubricants. This paper reviews the essential requirements of environmentally adapted lubricants, i.e., chemical composition, eco‐toxicity, biodegradability, bio‐accumulation, and eco‐labelling schemes, and life cycle analysis.
Application of the CONCAWE biodegradability test for oil products
Authors: Battersby N. S.
Published: July 2006

Information on the biodegradability of an oil product (or its components) is needed for classification and labelling purposes. The extent to which a product can be broken down by microbial attack is usually determined using a ‘ready biodegradability’ test (e.g., OECD 301 Test Guidelines). However, these methods are stringent screening tests and can often underestimate the extent to which a product can be removed from the natural environment by biodegradation. CONCAWE (the European oil companies’ organisation for environment, health and safety) has recently developed a test for determining the potential (or ‘inherent') biodegradability of oil products. This is often more useful for assessing the likely impact of an oil product in the event of its release into the environment. This paper gives examples of CONCAWE test results for a number of base fluids and formulated products, and compares these results with those obtained in a ‘ready biodegradability’ test. Guidance is given on the applicability of data that has been obtained using the CONCAWE method.
Delivering synthetic performance with VHVI speciality base fluids
Authors: Henderson H. Ernest , Swinney Brian , Steckle William M.
Published: July 2006

Historically, the best lubrication performance has been achieved by the use of synthetic fluids, such as polyalphaolefins or esters. Advanced commercial processing techniques for producing base oils through significant molecular change are now available. In many applications, automotive and industrial products formulated with these high‐quality API Group III speciality base fluids can achieve the same good performance as that from traditional synthetic fluids.

This paper represents continued work to understand and demonstrate features of very high viscosity index (VHVI) speciality base fluids. Ultimately, the performance of a finished fluid is the key market requirement. Actual field performance can vary dramatically, even among polyalphaolefin‐based formulations. Several examples are given to show that equivalent high‐level synthetic performance can be delivered through a synergistic balance of VHVI speciality base fluids and additive chemistry.
Traditional and new approaches to the development of wear‐resistant polymer composites
Authors: Friedrich Klaus
Published: July 2006

This overview describes the development of polymeric composites for operation with low friction and wear against steel counterparts, with special emphasis on injection‐mouldable short‐fibre‐reinforced thermoplastics. This work has aimed to optimise their friction and wear properties and to carry out systematic parameter studies using artificial neural networks; information is presented on the systematic development of continuous‐fibre polymer‐based composites with high wear resistance and on the prediction of their load‐bearing capacity using a finite‐element approach. Finally, some new steps towards the development of functionally graded tribo‐materials are described.
Effectiveness of the ion exchange/vacuum dehydration treatment of phosphate ester fluids
Authors: Collins Kellyanne G. , Duchowski John K.
Published: July 2006

Phosphate ester fluids are used in the electrohydraulic control systems of steam turbines. Conditioning agents are often added to the fluids to help prevent their performance being degraded by factors such as hydrolytic breakdown. However, some conditioning agents contain extractable metals that can react to form phosphate soaps or salts, which are also detrimental to the fluids' performance. This paper reports on the nature, origin, and mechanism of formation of these contaminants, with particular regard to those found on ‚last chance’︁ and high‐pressure system filters and in the phosphate ester fluids used by utility companies. Ion exchange/vacuum dehydration (IX/VD) treatment has been found to be effective in removing water, particulates, acid, and phosphate soaps from phosphate ester fluids. Three case studies are outlined wherein the IX/VD treatment of phosphate ester fluids was used to restore the fluids to their original specification. IX/VD treatment is shown to be a cost‐effective means of phosphate ester conditioning.
Behaviour of several lubricants for space applications under transient speed conditions
Authors: Glovnea R. P. , Spikes H. A. , Jones W. R.
Published: July 2006

Theoretical work has underlined the importance of squeeze effects in non‐steady‐state elastohydrodynamic (EHD) lubrication when parameters such as load, speed, or geometry vary cyclically. The present paper reports on the results of an experimental investigation into EHD film thickness under start‐stop, ball‐on‐flat contact conditions for four liquid lubricants used in space applications. The conditions studied are representative of those occurring in stepper motor bearing contacts. The lubricants investigated included a multiply alkylated cyclopentane (Pennzane™ SHF 2000), a branched perfluoropolyether (Krytox™ 143 AC), a polyalphaolefin (Nye™ 182), and a linear perfluoropolyether (Braycote™ BXL 413). Measurements were made at two frequencies (2 and 50 Hz) and two temperatures (25 and 80°C). At 50 Hz, corresponding to stop‐start time intervals of 10 ms, there was insufficient time during the stationary periods between motion for any significant collapse of the central film thickness to occur. However, partial collapse did take place at the contact peripheries. Since this collapse occurred in the inlet, it often produced a pronounced reduction in central film thickness during start‐up. It was also found that, during start‐up, a series of film thickness oscillations occurred, resulting in the film thickness becoming successively greater and less than the steady‐state value. This may have a significant effect on the pressure experienced by the contact. Although the four lubricants exhibited similar overall patterns of behaviour, there were considerable differences in the rate of film collapse and in the details of the film thickness reduction and oscillation.
Synthesis and biodegradability of some adipic and sebacic esters
Authors: Kolwzan B. , Gryglewicz S.
Published: July 2006

Using dimethyl adipate, dimethyl sebacate, and neopentyl glycol as starting materials, oligomeric esters with different ranges of molecular mass were synthesised. The transesterification reactions were catalysed with calcium methoxide. The esters have the physicochemical properties appropriate for use as synthetic lubricants. Both the adipic acid esters and sebacic acid esters are characterised by high biodegradability. The esters studied are considered to be environmentally friendly high‐performance functional fluids.
Synthesis and biodegradation of synthetic oils based on adipic and sebacic esters
Authors: Gryglewicz S. , Kolwzan B.
Published: July 2006

Used oils constitute a potential health hazard. Every year several million tons of used oils are released into the environment. At present, environmentally friendly synthetic oils, e.g., esters, are used as alternatives to conventional oils produced from petroleum. The aim of the present work has been to synthesise ester oils and determine their properties, particularly in terms of their biodegradability. Using dimethyl adipate, dimethyl sebacate, and neopentyl glycol as starting materials, oligomer esters with different ranges of molecular mass were synthesised. The syntheses were based on transesterification reactions catalysed by calcium methoxide. The degree of oligomerisation was closely correlated with the molar ratio of the esterification substrates. The esters showed physicochemical properties appropriate for use as synthetic lubricants. Both adipic acid esters and sebacic acid esters are characterised by high biodegradability. The biodegradability depends only slightly on the degree of oligomerisation of the ester molecules. The esters studied were considered as environmentally friendly high‐performance functional fluids.
Effect of temperature on the ageing behaviour of unsaturated ester‐based lubricants
Authors: Zhang X. , Murrenhoff H. , Weckes P. , Hölderich W.
Published: July 2006

The ageing behaviour of trimethylolpropane trioleate was investigated at different temperatures in a modified rotary bomb test apparatus. Some physicochemical properties of ageing oil samples, such as acid value, kinematic viscosity, and iodine value, were measured. The oil samples were analysed using gas chromatography, gas chromatography‐mass spectrometry, and gel permeation chromatography to assess the influence of temperature on the ageing behaviour of ester‐based oils. The results revealed that an increase in temperature could greatly speed up the ageing reaction and increase the formation of decomposition products. However, the degree of oil ageing remained similar when the same quantity of oxygen was consumed.
Phosphate esters with a complex alkyl‐aryl structure considered as tribological fluids
Authors: Mirci Liviu E. , Herdan Jean M. , Boran Sorina
Published: July 2006

This paper presents results of reserch carried out to produce synthetic ester oils with adequate tribological properties, which could also act as antiwear additives. By varying the molar relationship between aliphatic alcohols of variable chain length and a special alcohol with complex alkyl‐aryl structure, namely 2‐[(o‐sec‐butyl)phenoxy]ethanol, two series of new phosphate esters have been synthesised. The influence of the aryl content and the effect of the length of the aliphatic chain on the characteristics of these esters as base oils, and on their qualities as antiwear additives, have been investigated.
Effect of additive molecular structure on friction
Authors: Beltzer M. , Jahanmir S.
Published: July 2006

Work is reviewed on the adsorption properties of typical friction reducing additives, at monolayer coverage, operating in the boundary lubrication regime. It looks at adhesive interactions, lateral interactions between adsorbate molecules, and transition temperatures. The adsorption properties of typical friction reducing additives can be accounted for by hydrogen bonding to surfaces and the lateral interactions between adsorbate molecules.
Solution properties of polymethacrylate VI improvers
Authors: Neveu C. , Huby F.
Published: July 2006

This paper reports an attempt to determine the applicability of Kraemer and Huggins equations of dilute solutions, to the VI improver polymethacrylate. The equations are used to provide an estimate of the intrinsic viscosity of the polymer in a given solvent at a given temperature.
Pour point depressants in lubricating oils
Authors: Denis J.
Published: July 2006

This article begins by describing the main chemical families of pour‐point depressant additives. The normal paraffins remaining in the oil after dewaxing crystallize at low temperature in the form of very thin platelets made up of several layers of associated molecules that are superposed in spirals. These platelets become entangled and prevent the flow of oil. Additives work either by adsorption or by cocrystallization, enhancing the growth of lamella thickness, thus making them less prone to entanglement.
Literature review of OCP viscosity modifiers
Authors: Marsden K.
Published: July 2006

Olefin copolymers and terpolymers (OCPs) are used as viscosity modifiers in a large proportion of the European and world multigrade oil market. The polymer properties of the basic ethylene propylene polymers are critical to the physical characteristics of the final lubricant and its engine performance. The important parameters are discussed. Ethylene propylene polymers intended for use in other industrial applications should be checked thoroughly to avoid potential field problems. Modifications of these speciality OCPs to dispersant polymers enhance diesel and dispersant lubricant properties, enabling the most severe lubricant performance requirements to be met. The paper also reviews developments reported in the literature on the production and handling of the products together with their application, particularly with reference to their effect on low temperature properties, engine cleanliness, wear and fuel economy of the lubricant.
Effect of oil environments on the initiation of fatigue cracks and propagation of small cracks in plain carbon steel specimens
Authors: Goto M. , Miyagawa H. , Nisitani H.
Published: July 2006

In fatigue tests of plain carbon steel specimens in air, fatigue life is taken up mainly by the life in which a crack propagates from its initial size up to about 1 mm. This means that the behaviour of a small crack in the oil environment must be known in order to evaluate the effect of oils on fatigue life.

In this paper, using a series of base oils of different viscosity grades, the effects of oils on fatigue damage are investigated in rotating bending fatigue tests of annealed 0.34% carbon steel plain specimens. Successive detailed observations of the specimen surface are made in order to study the fatigue processes of micro‐crack initiation and small crack propagation. The physical background of the effect of oil environments on fatigue behaviour is shown, and a method for predicting fatigue life in oil environments is discussed.
Velocity fields in grease lubricated contacts
Authors: Mutuli S. , Bonneau D. , Frène J.
Published: July 2006

This paper examines the behaviour of a grease lubricant in open contacts. Analytical expressions of velocity profiles for a Bingham fluid are presented for three cases: flow where all the film thickness is sheared; where a non‐sheared core zone is attached to one contact surface; and where a core zone floats in the middle of the film. An experimental study is described which used visualization through illumination across contact surfaces. Results are presented for two modes of operation: contact of cylinder and fixed plane surface, and pure rolling of two cylinders. In the former case, nine zones of operation are identified.