The present subject matter describes a method for preparation of a lubricant dispersed with carbon nanotubes (CNTs) and a lubricant dispersed with the CNTs prepared thereof. The method comprises ball milling the CNTs and purifying the ball milled CNTs to remove impurities in the CNTs. The method also comprises oxidizing surfaces of the purified CNTs by adding the purified CNTs to a solution comprising at least one oxidizing acid and then refluxing the solution. The oxidized surfaces of the CNTs are modified by adding the CNTs to a solution comprising at least one fatty acid to obtain surface modified CNTs. The method also comprises dispersing the surface modified CNTs in a lubricant to obtain the lubricant dispersed with CNTs.

A lubricant composition includes a base oil present in an amount of greater than 70 parts by weight per 100 parts by weight of the lubricant composition and an antioxidant. The antioxidant has the structure: wherein each X is independently CH or N, so long as at least one X is N. A is an electron donating group that (1) has an atom having at least one lone pair of electrons that is bonded directly to the aromatic ring or (2) is an aryl or alkyl group. Z is chosen from a hydrogen atom and an electron donating group that has an atom having at least one lone pair of electrons that is bonded directly to the aromatic ring or is an aryl or alkyl group.

##STR00001##

A lubricant composition includes a base oil present in an amount of greater than 70 parts by weight per 100 parts by weight of the lubricant composition and an antioxidant. The antioxidant has the structure: wherein each X is independently C-A or N, so long as at least one X is N but no more than two of X are N. Moreover, A is H, cyano or an electron donating group that: (1) has an atom having at least one lone pair of electrons that is bonded directly to the aromatic ring; or (2) is an aryl group or alkyl group. Further, each R is independently H, an alkyl group, or aryl group and each R is independently an alkyl group or an aryl group.

##STR00001##

A lubricating oil composition, a method of reducing low-speed pre-ignition (LSPI) in a direct-injected spark-ignited internal combustion engine, and a use of a lubricant composition to reduce UPI events in such an engine. Preferably, the composition comprises a detergent package comprising a borated calcium detergent, wherein the detergent package provides a calcium content in the composition of at least 0.12 mass %, based on the total mass of the composition, and wherein the borated calcium detergent provides a boron content in the composition of at least 100 ppmm, based on the total mass of the composition. Optionally, the composition comprises a first detergent comprising a calcium detergent, and a second detergent comprising a borated calcium detergent.

The invention relates to low molecular weight hydrogenated polybutadienes and to a method for the preparation of these polymers. The invention is also directed to lubricant compositions comprising these polymers and uses thereof.

A method for improving filterability, while maintaining or improving antifoaming performance, of a lubricating oil in an engine or other mechanical component lubricated with the lubricating oil by using as the lubricating oil a formulated oil. A method for improving antifoaming performance, while maintaining or improving filterability, of a lubricating oil in an engine or other mechanical component lubricated with the lubricating oil by using as the lubricating oil a formulated oil. The formulated oil has a composition including a lubricating oil base stock as a major component, and at least one antifoam agent, as a minor component. A lubricating oil having a composition including a lubricating oil base stock as a major component, and at least one antifoam agent, as a minor component. The antifoam agent is a silicone composition having a highly branched functionalized silicone backbone. The lubricating oils are useful as automotive gear lubricating compositions.

The present disclosure generally relates to a lubricating oil composition for improving corrosion resistance and maintaining TBN in an internal combustion engine.

A defoaming agent comprising: a polymer comprising a repeating unit represented by the following general formula (1):

##STR00001##

where in the general formula (1), X.sup.1 is a repeating unit obtainable by polymerization of an ethylenic unsaturated group; Y.sup.1 is a side chain comprising a linear or branched polysiloxane structure, the polysiloxane structure comprising a repeating unit represented by the following general formula (2) and having a polymerization degree of 5 to 300; and Z.sup.1 is a linking group linking the repeating unit X.sup.2 and the side chain Y.sup.1;

##STR00002##

wherein in the general formula (2), R.sup.1 and R.sup.2 are each independently an organic group having a carbon number of 1 to 18.

A defoaming agent including a polymer, the polymer including a repeating unit represented by the following general formula (1); and a repeating unit represented by the following general formula (3):

##STR00001##

wherein in the general formula (1), X.sup.1 is a repeating unit obtainable by polymerization of a first ethylenic unsaturated group; Y.sup.1 is a side chain including a linear or branched polysiloxane structure, the polysiloxane structure having a polymerization degree of 5 to 300; and Z.sup.1 is a linking group linking the repeating unit X.sup.1 and the side chain Y.sup.1;

##STR00002##

wherein in the general formula (3), X.sup.2 is a repeating unit obtainable by polymerization of a second ethylenic unsaturated group, Y.sup.2 is a C.sub.1-30 hydrocarbyl side chain; and Z.sup.2 is a linking group linking the repeating unit X.sup.2 and the side chain Y.sup.2.

The presently disclosed technology relates to a nano-additives to improve the performance of lubricants, oils, and greases. More specifically, the presently disclosed technology relates to applying capped metal oxide nanoparticles, such as capped zirconia nanoparticles, in the lubricants to produce a tribofilms on the lubricating surfaces to provide wear protection to the said surfaces. Also, the interaction of the capped zirconia nanoparticles with other commonly used additives in lubricants may further optimize the performance of the resulting tribofilms.