Knowledge

This paper examines the effect of dispersant and anti-wear additives on fretting wear in lubricated bearing steel contacts. Reciprocating sliding ball-on-flat fretting tests with a stroke length of 50 μm have been carried out on steel-to-steel contacts in both dry and lubricated conditions. Wear and friction coefficient have been measured, and surface characterisation has been carried out using optical techniques to investigate fretting wear. The presence of base oil reduces fretting wear markedly compared to dry conditions, but fretting damage is still observed at low reciprocation frequencies. As frequency is increased, there is a transition from oxidative to adhesive/scuffing damage. The anti-wear additive ZDDP is effective in forming a tribofilm on the surfaces and reducing visible oxidation and wear. A succinimide dispersant also reduces the accumulation of solid debris but does not alleviate wear damage. The combination of both ZDDP anti-wear additive and dispersant in base oil appears to provide significant protection against fretting wear.

Nanoparticles have the potential to become a new classification of lubricating oil additives. Metal oxide nanoparticles have demonstrated the ability to create antiwear films through a tribosintering type process. Commercially prepared, spherical zirconia (ZrO2) nanoparticles with an average particle size (APS) of 5 nm and functionalized with a hydrocarbon ligand were dispersed in a polyalphaolefin (PAO) base oil, producing a 10 nm stabilized ZrO2 nanofluid. The resulting nanofluid was characterized including thermal conductivity and viscosity as a function of nanoparticle concentration. Long-term stability was verified using dynamic light scattering (DLS) and APS was quantified as function of time. A 10 %wt ZrO2 nanofluid maintained a 10 nm APS over 25 months, with no signs of agglomeration or sedimentation, and redispersion was not necessary before testing. The tribological performance of several concentrations of ZrO2 nanofluids was characterized with a ball-on-disk tribometer. Tribofilm growth over time was collected via optical interference imaging.

This invention involves the development of less corrosive, high performing organic compounds with applications as additives in lubricants. Lubricants containing these compounds have demonstrated improved performance with respect to friction reduction, wear protection, and copper and lead corrosion. In particular, the compounds of the invention are N-[3-[(2,3-dihydroxypropyl)(3-alkoxypropyl)amino]propyl]alkylamides, and unsaturated or branched N-[2-[(2,3-dihydroxypropyl) (2-hydroxyethyl) amino]ethyl]-alkylamides.
The claimed compounds represent a new class of additives capable of meeting or exceeding the frictional and wear performance of traditional additives while significantly reducing the severity of the observed copper and lead corrosion. This inventive class of compounds is particularly useful in both passenger car motor oil and heavy-duty diesel engine oil applications where high performing, more durable friction modifier and/or anti-wear additives are required in terms of oxidative and hydrolytic stability.

Low molecular weight, highly branched polyolefins are provided. Also provided are catalyst-mediated methods of making the low molecular weight, highly branched polyolefins and a catalyst system for carrying out the methods. The catalyst system is a homogeneous catalytic system that includes a single-site organozirconium complex and hydrocarbon-soluble perfluoroarylborate co-catalyst that is highly active for the oligomerization of olefin monomers in non-polar media.

This study aims to evaluate the physicochemical and sensory properties of oral nutritional supplements (ONSs). High physical stability was measured in ONSs with mean particle sizes <0.33 !m and viscosity >19.3 mPa·s. ONSs formulated with dairy-soy protein mixtures displayed low friction coefficients, whereas ONSs containing dairy proteins alone had high friction coefficient values in the boundary regime. Sensory analysis revealed low to medium liking across the products and the highest preference was found in samples with the highest perceived ‘sweetness’, ‘vanilla aroma’ and ‘thickness’. The results will underpin the formulation of novel ONSs with good physical stability and sensory acceptability.

Machine elements such as rolling bearings and gears transmit forces and permit relative motion in concentrated contacts, whereby elastohydrodynamic lubrication (EHL) plays a major role in surface protection. The friction/traction in a rolling/sliding EHL contact is hard to predict due to non-Newtonian rheology and concomitant thermal effects. In the last decade, much effort has been made to study the EHL traction using reference fluids. However, considerable discrepancies still exist between predictions and measurements. This work continues the effort to predict the EHL traction with model fluids (mainly with squalane) and investigates the influence factors that lead to the differences between simulations and experiments. An EHL model has been developed for traction prediction accounting for non-Newtonian and thermal effects by embedding fluid models of thermo-physical-rheological properties (such as viscosity, thermal conductivity, shear thinning, and limiting shear stress) supported by independent high-pressure measurements. On the experimental aspects, traction curves have been measured on two traction machines with different contact geometries, i.e. twin-disc and ball-on-disc.

Wearing of UHMWPE components used in several joint prosthesis has been approached from many perspectives; for instance, developing composites to improve upon the mechanical resistance of the bearing material, treating the surface with plasma, and texturing the surface to improve its wettability. This work reports the experimental behavior of the UHMWPE/AISI 316L tribopair, lubricated with distilled water, operating under the arthrokinematics, and loading conditions prescribed by ISO 14243-3. The UHMWPE surface was micro-textured to determine the tribological effect. Contrary to our expectations, the experiments rendered values of coefficient of friction higher than for the smooth surface throughout the walking cycle. A regression model obtained from the experimental data showed that the coefficient of friction has an inverse relation to the load, and direct with the entrainment and sliding-to-rolling ratio.

This study investigates the effect of substituting sunflower oil with two starch-based fat-replacers on the rheological and lubricating properties, as well as the sensory properties of reduced-fat mayonnaise-type emulsions. Lipid-modified maize starch fat replacers containing amylose–lipid complexes, maize starch with 1.5% stearic acid and maize starch with 2% monoglyceride, are used to formulate reduced-fat mayonnaise-type emulsions at 0% (full-fat control), 50%, 80%, and 98% level of oil replacement. Reduced-fat emulsions containing starch/monoglyceride are rated similar (p > 0.05) to the full-fat mayonnaise at all the oil replacement levels in terms of smoothness, creaminess, melting, and mouth-coating. They also have similarities in terms of thickness and easy-to-swallow sensory attributes, up to a 50% substitution level. For the corresponding starch/stearic acid emulsions, the smoothness, thickness, creaminess, and mouth-coating attributes are rated lower while the melting and easy-to-swallow attributes are rated higher than for the starch/monoglyceride emulsions. In general, all the reduced-fat emulsions exhibit good lubrication. The ability of the reduced-fat emulsions to support the highly viscous structure provided by the presence of amylose–lipid complexes in the fat replacers is better for the starch/monoglyceride fat replacer than for the starch/stearic acid fat replacer.

The present disclosure provides for a lubricant formulation and a method of forming the lubricant formulation for use in an internal combustion engine. The lubricant formulation includes a base oil and an esterified oil-soluble polyalkylene glycol (E-OSP) of Formula (I): R1 [O(R2O)n(R3O)m(C═O)R4]p wherein R1 is a linear alkyi having 1 to 18 carbon atoms, a branched alkyl having 4 to 18 carbon atoms or an aryl with 6 to 30 carbon atoms; R2O is an oxypropylene moiety derived from 1, 2-propylene oxide; R3O is an oxvbutvlene moiety derived from butylene oxide, wherein R2O and R3O are in a block or a random distribution; R4 is a linear alkyl with to 18 carbon atoms, a branched alkyl with 4 to 18 carbon atoms or an aryl with 6 to 18 carbon atoms; n and m are each independently integers ranging from 0 to 20 wherein n+m is greater than 0, and p is an integer from 1 to 4.