bluuebunny/crossref_metadata_2025_split huggingface dataset:
Application of waste carboxylic acids to the manufacture of biodegradable polyolester base oils
Authors: Beran E. 
Published: July 2006

AbstractThe results described in this paper represent a contribution towards finding feedstocks, such as monocarboxylic acids, for the production of polyolester base oils. The research has shown that it is possible to obtain a mixture of monocarboxylic (butyric, valeric, and caproic) acids from the waste stream produced by the catalytic oxidation of cyclohexane to cyclohexanone in the industrial production of caprolactam. The mixture of C4—C6 carboxylic acids separated from this waste by distillation was used to esterify neopentyl alcohols such as trimethylolpropane (TMP) and pentaerythritol (PE). Thus, polyolester synthesis was strongly dependent on the choice of suitable catalyst and the neturalisation of unreacted acids. Polyolester oils obtained from TMP or PE with monocarboxylic C4—C6 acids have better physicochemical properties than conventional mineral oils, namely ISO 10 or ISO 22, including higher viscosity indices, higher flash points, lower pour points, and lower volatilities. In addition, the polyolesters tested are readily biodegradable under the conditions of the CEC‐L‐33‐T‐82 test and the Zahn‐Wellens test.
Low‐temperature characteristics of synthetic fluids
Authors: Boyde S. 
Published: July 2006

AbstractThe low‐temperature fluid properties of synthetic base fluids are described, showing how these properties are related to the molecular structure of the base fluid. Examples are given of how the principles of molecular design can be used to improve the low‐temperature properties of synthetic base fluids, focusing on esters derived from both natural and petrochemical raw materials. Results of studies using calorimetric and spectroscopic methods, including differential scanning calorimetry and nuclear magnetic resonance are presented, showing how these techniques can be used to give more detailed insight into the changes occurring in fluids at low temperatures.
Synthetic aluminium complex grease: A tribological evaluation using a four‐ball test
Authors: Singh Tarunendr , Bhan A. K. 
Published: July 2006

AbstractThis paper describes the preparation and performance evaluation of a synthetic aluminium complex grease. The aluminium complex grease was prepared in situ by reacting stearic acid and benzoic acid in the presence of a synthetic base oil, polyalphaolefin. The preparation of the soap (aluminium benzoate stearate hydroxide) was monitored using Fourier transform infrared. Two different extreme‐pressure additives blended with the prepared aluminium complex grease were evaluated for their extreme‐pressure activity in four‐ball and Timken tests. These greases exhibited higher Timken OK loads (60 lb), lower values of wear‐scar diameter at higher loads, and higher values of weld load in the four‐ball test than the aluminium complex grease without additive. The blended greases were also found to pass rust and corrosion, oxidation‐stability, and shear‐stability tests. The topography of the specimens after four‐ball testing was studied with scanning electron microscopy.
Base fluid parameters for elastohydrodynamic lubrication and friction calculations and their influence on lubrication capability
Authors: Larsson Roland , Kassfeldt Elisabet , Byheden Åke , Norrby Thomas 
Published: July 2006

AbstractIn this study, base fluid parameters for elastohydrodynamic lubrication (EHL) and friction analyses have been determined experimentally. The viscosity at atmospheric pressure, η0, the pressure‐viscosity index, α, and the EHL friction coefficient, γ, are important parameters in EHL theory and they are crucial in the selection of efficient lubricants for different applications. This investigation focuses on three important lubrication mechanisms: the capability of forming a separating lubricant film, the friction generated in a lubricated contact, and the height of pressure peaks, such as the outlet pressure spike and pressure ripple caused by surface roughness. The influence of different lubricant parameters on these three mechanisms is discussed. The value of α is measured in a Couette high‐pressure viscometer, and the value of γ is obtained from a jumping‐ball device. Other parameters discussed are temperature‐viscosity coefficient, β, bulk modulus, B0, thermal conductivity at atmospheric pressure, λ0, and heat capacity unit volume, ρcp0.A comparison between traditional mineral base oils and environmentally adapted oil based on rapeseed oil and synthetic esters contributes to the further understanding of the performance of these new materials in lubrication applications. It is shown that rapeseed oil and synthetic esters have good lubricating properties and are, in most cases, better than mineral oils.
Lubricity characteristics of ethyl hexyl esters of mono‐, Di‐, and triethenoic acids
Authors: Sharma Anju , Chhibber V. K. , Pal Mahendra , Anand O. N. 
Published: July 2006

AbstractEthyl hexyl esters of oleic, linoleic, and linolenic acids were synthesised and thermally polymerised to obtain products with viscosities in the range of hydrocarbon lubricants at 100°C (11–22 cSt). Molecular weight, elemental analysis, IR, 13C NMR, and intrinsic viscosity data showed that most of these derivatives are mixtures of monomers, dimers, and trimers and have linear and cyclic products with predominantly trans characteristics.The lubricity characteristics were determined on a friction and wear tester under conditions of thick‐film lubrication. A comparison was made with hydrocracked hydrocarbon lubricants of comparable viscosities at 100°C and comparable viscosity indices.It is inferred that all the esters maintained relatively thicker surface films and much lower friction coefficients than the hydrocarbon oils. The wear‐scar data show that the antiwear characteristics of polymerised ethyl hexyl oleate and linoleate are only slightly inferior to those of the hydrocarbon oils, but at higher temperatures their antiwear characteristics rapidly deteriorate while the friction coefficients markedly increase and become comparable to those of hydrocarbon oils. These studies are being undertaken with a view to selecting and modifying vegetable oils containing mixtures of fatty acids for obtaining esters of outstanding friction, wear, and film‐forming characteristics.
A comparative life cycle assessment of the manufacture of base fluids for lubricants
Authors: Våg C. , Marby A. , Kopp M. , Furberg L. , Norrby T. 
Published: July 2006

AbstractA comparative life cycle assessment (LCA) study of three types of base oils used in the manufacture of hydraulic fluids has been carried out, and is reported here. The fluid types investigated are a mineral oil, a synthetic ester, and a rape seed triglyceride oil. The applications chosen for the finished lubricants are in mobile hydraulic systems in forestry operations, some of which are almost 100% total loss applications. The scope and limitations of the LCA model are discussed, and conclusions drawn concerning the application of LCA models as evaluation tools for the development of environmentally adapted lubricants. The methodology used is compatible with the ISO 14000‐type industrial standard.
Eco‐friendly base fluids for lubricant oil formulations
Authors: Bisht R. P. S. , Kaul Savita , Nagendramma P. , Bhatia V. K. , Gupta A. K. 
Published: July 2006

AbstractThere is an increasing move towards the use of environmentally safe lubricants. However, the development of a common biodegradable base stock that could replace conventional ones is a big challenge. Synthetic lubricants, whether synthetic hydrocarbons, organic esters, or others, all have problems associated with their use. However, in general terms synthetic lubricants protect better, last longer, and outperform their conventional mineral‐based counterparts in certain applications. Future lubricant specifications in view of the demand for improved performance to meet stringent environmental regulations are the main drivers for new technological developments. As part of a study to produce polyol ester lubricant base stocks from C5 polyols and C6‐C14 carboxylic acids in the presence of eco‐friendly catalysts, a series of products has been synthesised. A biodegradable lubricant formulation for automotive transmission fluids has been developed based on a synthesised product as a base fluid. This paper reports on the physico‐chemical characteristics and performance evaluation results of this formulation, which is a promising base stock for automotive transmission fluids.
Structurally modified polyglycols as biodegradable base stocks for synthetic lubricants
Authors: Beran E. 
Published: July 2006

AbstractLubricants of novel formulation should have low toxicity and be readily degraded in the environment. Polyglycols (PAGs), which are homopolymers of ethylene, propylene, or (rarely) butylene oxides, or are copolymers of ethylene and propylene oxides, constitute a group of chemical raw materials with a wide range of industrial applications. They are also used in the synthetic lubricant industry. The properties and applicability of certain PAGs depend on a variety of factors, such as the conditions of preparation, the type of starter and alkylene oxide used, and parameters controlling the structure and molecular weight of the final product. However, of the wide range of available PAGs, not many display properties that might be useful in the production of lubricants, and not many fulfil the biodegradability criteria required in standard test procedures (e.g., OECD) for environmentally friendly base oils. Studies carried out to obtain a novel assortment of base oils have shown that the modification of commercial PAGs by esterification of their hydroxyl groups (both in polyoxyalkylenediols and polyoxyalkylenetriols) yields products with the desired properties. For example, esterification of polyoxyethylenediol of a molecular weight of 400 modified its viscosity, pour point, and water solubility, but did not affect its biodegradability (over 80% in Zahn‐Wellen's test: ISO 9888; OECD 302B).
Sliding wear behaviour of PEEK‐PTFE blends
Authors: Hufenbach W. , Kunze K. , Bijwe J. 
Published: July 2006

AbstractThe role of PTFE in tailoring the tribological performance of PEEK is not clear from the literature, and conflicting evidence is reported about its ability to improve friction, wear, or both. Moreover, little has been reported on the optimum composition of such blends for the best possible combination of mechanical and tribological properties. Hence, in this work various blends of PEEK with PTFE have been injection moulded and characterised for their mechanical properties. Their friction and wear behaviour was evaluated using a pin‐on‐disc machine. It was observed that the inclusion of PTFE powder not only removed scuffing problems associated with the friction behaviour of PEEK, but also improved both friction and wear characteristics. A blend with 7.5 wt. % PTFE showed the best wear behaviour, while a blend with 30 wt.% PTFE exhibited the best friction performance. A concentration of 7.5 wt. % PTFE was thought to be the optimum amount for the best possible combination of mechanical and tribological properties.
Wear reduction using some extreme pressure lubricant additives and their tribological studies
Authors: Mammen A. , Agarwal C. V. , Verma V. K. 
Published: July 2006

AbstractCertain S‐containing organic compounds were synthesized and their extreme pressure (EP) properties assessed. The series of compounds studied were: S‐alkylisodithiobiurets, alkyl‐S‐alkyl xanthates, S‐alkylisothioamides, S‐benzylisothiocarbamides and 1‐formamidino‐2‐benzyliso‐3‐arylthiocarbamides. These additives were compared with a commercial additive. The tribological end effects were studied using a Scanning Electron Microscope. Some of the compounds tested were found to be effective EP additives.Wherever possible, a plausible explanation for the enhanced activity has been given, and we have attempted to correlate the effect of substituents on efficiency. Also, the effect of additives on balls of different compositions is discussed. The possibility of replacing the costly chromium steel alloy balls by less costly mild steel balls is suggested.Some of the additives developed are found to be effective on balls of certain compositions while they are a total failure on the chromium steel balls. The studies reveal that some additives are effective on mild steel balls as well as chromium alloy steel balls. They can be very good substitutes for commercial additives with bearing balls of standard composition.As chromium alloy steel balls are much costlier there is a need to replace expensive alloy steel balls with cheaper low carbon steel balls, for certain specific purposes. This can be achieved by using suitable indigenous additives that are found to be effective on low carbon steel balls.
Micellar structure of alkaline earth metal alkylarylsulphonate detergents
Authors: Tricaud C. , Hipeaux J. C. , Lemerle J. 
Published: July 2006

AbstractOverbased and neutral magnesium and calcium salts of sulphonic acids were prepared, these salts having a very complex micellar structure when added to a lubricant oil. Using solutions in isooctane, the authors studied this structure by ultracentrifugation. The following results were obtained: a correlation between the alkaline reserve of additives and the size of the micelle; a difference in the size of the micelle in relation to the earth metal used; and the influence of the solvent used in the evolution of the micellar structure in the solution.
The effects of engine oil additives on valve train wear
Authors: Shirahama S. , Hirata M. 
Published: July 2006

AbstractPreventing valve train wear in automotive engines is one of the most important properties of an engine oil. However, the influence of engine oil additives on valve train wear has not been sufficiently clarified.In this investigation, the antiwear performance of additives (such as ashless dispersants, metallic detergents and zinc dithiophosphate ‐ ZDTP) and the influence of the interaction of the additives were evaluated.Secondly, metallic detergents were considered. An overbased calcium sulphonate and an overbased phenate were found to have good anti‐scuffing performance when evaluated in engine tests and in Falex wear tests. However, from the results of four‐ball tests, these additives did not appear to have many extreme pressure properties. From surface analyses, it was determined that a calcium carbonate film was formed on the sliding surface of the Falex test piece, and this film provided good protection against wear.Finally, the interaction of ZDTP, succinimides and calcium detergents and their influence on valve train wear were studied. The decomosition temperature of ZDTP increased with certain additives. including the succinimide. As a result, scuffing was more prone, at temperatures below those increased temperatures. Also, changes in additive concentration on the sliding surface, due to competitive adsorption, altered the antiwear performance of the oil.
Effect of sulphur‐type extreme‐pressure additives on wear in rolling‐sliding contact
Authors: Masuko M. , Akatsuka K. , Okabe H. 
Published: July 2006

AbstractThis paper looks at the wear of steel under lubricated rolling‐sliding contact, with two paraffinic oils and a pure n‐hexadecane. A two‐disc apparatus was used, with a constant applied load, the surfaces being analyzed by X‐ray photoelectron spectroscopy. The oils were tested with and without additives (dibenzyl disulphide and diphenyl disulphide), and the differences analyzed.
The influence of chemical structure of certain nitrogen‐containing organic compounds on their antiwear effectiveness: The critical role of hydroxy group
Authors: Wei D. , Han X. , Wang R. 
Published: July 2006

AbstractCertain nitrogen compounds and their derivatives used as antiwear additives in base stocks have been tested on a four‐ball machine and an HQ‐1 tester for their relative antiwear effectiveness. The preliminary results indicate that the heterocyclic nitrogen compounds, in general, have a beneficial effect on the antiwear performance of base stocks. Hydroxy groups involved in some nitrogen‐containing compounds have been found to improve their antiwear performance significantly. In particular, one of the hydroxy‐substituted benzothiazoles is most effective in wear reduction and anti‐scuffing. However, the beneficial effect of a hydroxy group has not been observed for short‐chain amines.
Critical conditions for wear in pivoted follower valve train systems
Authors: Bell John C. 
Published: July 2006

AbstractThere are numerous wear problems associated with the use of pivoted cam follower valve train systems in modern high‐speed automotive engines. These problems have led to the introduction of an increasing number of engines of this type as specification tests to assess the antiwear performance of lubricants. Critical conditions for wear in these systems have been identified by the application of a steady‐wear process model to the kinematic analysis of the cam/follower contact cycle. The positions of maximum wear identified by this technique showed better agreement with worn engine components than the more commonly used criteria of maximum contact pressure and oil film thickness.
Ashless antioxidants, copper deactivators and corrosion inhibitors: Their use in lubricating oils
Authors: Hamblin P. C. , Kristen U. , Chasan D. 
Published: July 2006

AbstractThis paper reviews the use of copper deactivators and iron corrosion inhibitors in lubricating oils. The auto‐oxidation process is described in terms of initiation and chain propagation, branching and termination, and the primary and secondary oxidation inhibitors are described. Copper deactivators and corrosion inhibitors nature and action are discussed, and the paper also examines the applications for these additives.
Measurement of lubricating film thickness, temperature and pressure in gear contacts with surface topography as a parameter
Authors: Peeken H. , Ayanoglu P. , Knoll G. , Welsch G. 
Published: July 2006

AbstractThin film transducers, sputtered onto a tooth flank, are used to measure temperature, pressure and oil film thickness profiles in gear contact. The former two are resistance sensors, while the film thickness sensor functions as a capacitive transducer. Experiments were carried out with ground and hobbed gears. The measurements are repeated after the tooth flank has been polished. The differences of the measured values for the ‘rough’ and ‘smooth’ surfaces are used for comparisons between differently machined surfaces.An EHD simulation programme has been developed which calculates film thickness and contact pressure, also taking surface roughness into account.
Prediction of lubrication regimes of concentrated contacts
Authors: Schipper D. J. , Vroegop P. H. , De Gee A. W. J. 
Published: July 2006

AbstractFriction experiments are performed on lubricated concentrated contacts (LCCs) to obtain the transitions EHL‐ML and ML‐BL as a function of the operational conditions under which these contacts operate. A transition diagram is developed to determine the lubrication mode of an LCC as a function of the operational conditions. In this investigation the LCCs operated macroscopically in the lubricants' liquid state regime.
An investigation of the effects of some motor oil additives on the friction and wear behaviour of oil‐soluble organomolybdenum compounds
Authors: Wei D. , Song H. , Wang R. 
Published: July 2006

AbstractThe compatibility of oil‐soluble organomolybdenum compounds with some motor oil additives (detergent, dispersant, rust inhibitor and ZDDP) has been investigated on a four‐ball machine and a SRV tester. Preliminary results indicated that a combination of two agents might have either synergistic or antagonistic effects on the friction and wear performance of the organomolybdenum compounds, although many combinations were shown to be synergistic. The interactions between two agents were primarily determined by the additive types, additive concentrations and test temperatures.It was also found that the presence of calcium sulphonate detergent was particularly beneficial to molybdenum dithiophos‐phate and molybdenum dithiocarbamate in terms of friction reduction and wear reduction at temperatures in a certain range. The induction period of the organomolybdenum compounds was also reduced. Surface analysis results suggested that the synergistic effects were closely related to the formation of thick films, which were rich in molybdenum and sulphur, on rubbing surfaces.
Resistance of ashless dispersant additives to oxidation and thermal decomposition
Authors: Bartha L. , Hancsok J. , Bobest E. 
Published: July 2006

AbstractAshless dispersants of the type of alkenyl‐succinic anhydride derivatives were prepared. The resistance of these compounds to oxidation and thermal decomposition was investigated by thermoanalytical methods. Results were compared to those obtained in a panel coking test of these additives at 300°C in a multifunctional package. It was found that data obtained by DSC could be used for rating the stability of polyisobutenyl‐succinimides against thermo‐oxidation.
An analysis of heat transfer in the thin‐layer transducer used for the measurements of EHD contact parameters
Authors: Hofman S. , Bartz W. J. 
Published: July 2006

AbstractThin‐layer transducers, which are mainly used for the measurement of the EHD contact parameters, have to be attached to an isolating layer separating it from the steel roller. The isolating layer, made of SiOx or Al2O3, disturbs heat flow in relation to the real contact. This paper presents a solution for the system of two heat conduction equations for a two‐layer body: SiOx‐steel. The boundary conditions reflect the real situation during the measurements carried out by means of these transducers. The solution was obtained for an assumed temperature distribution of the isolating layer surface. Computation results for two different temperature distributions of the surface and for various values of the SiOx‐layer thickness are also presented.
The performance of some antiwear additives and interference with other additives
Authors: Palacios J. M. 
Published: July 2006

AbstractThis paper reports work on the evolution of films formed by some antiwear additives. Between having an additive solution in a fresh lubricant and the actual deposition of protective films on the rubbing surfaces there is a gap during which the normal actions of a given additive may be affected by the presence of another additive.Film thickness is one of the most important parameters affecting wear. Interference between additives can change the chemical composition and the thickness of the films formed and, consequently, can modify the antiwear properties of the original additive.
Interaction of different types of additive with oil‐soluble metal salts ‐ homogeneous catalysts of oxidation
Authors: Vipper A. B. , Glavati O. L. 
Published: July 2006

AbstractThe interaction of zinc dithiophosphate and phenolic antioxidants with metal naphthenates, mainly with copper naphthenate, has been investigated. A complex compound is formed on the interaction of zinc dithiophosphate with copper naphthenate; this has a noticeable influence on the antioxidation effectiveness of zinc dithiophosphate. The possibility of increasing the antioxidising action of zinc dithiophosphate through its combination with a copper passivator is shown. The formation of complex compounds on the interaction of phenolic antioxidants with copper naphthenates depends on the structure of these additives.