Provided are functional polymers based on functionalized styrenic monomers including a nitrogen-containing moiety, other than as pendant to the phenyl ring that are polymerized from addition-polymerizable monomer compositions including amine-derivatized alpha-methyl styrene (ADAMS) monomers according to structure (I).

##STR00001##

wherein k is an integer from 1 to 3, preferably 2; wherein R.sub.1 is a methyl group or a phenyl group and R.sub.2 is a benzyl group, or wherein R.sub.1 and R.sub.2 are connected to form a moiety containing one 6-membered ring, with four carbons, bearing an O or NCH.sub.3 group at the 4-position of the 6-membered ring; wherein R, in structure (I), is hydrogen, a phenyl ring co-attached at two neighboring ring carbon positions with the phenyl ring shown so as to form a naphthalene assembly, a phenyl group attached at a single carbon of the phenyl ring shown, a C.sub.1-C.sub.4 hydrocarbyl group (such as a methyl group), a C.sub.1-C.sub.6 hydrocarbyl group containing 1 to 4 additional heteroatoms (such as O, N, S, P, Se, and combinations thereof). Also provided are methods of using such functional polymers in lubricating oil compositions.

Provided are functional polymers based on functionalized styrenic monomers including a nitrogen-containing moiety, other than as pendant to the phenyl ring that are polymerized from addition-polymerizable monomer compositions including amine-derivatized alpha-methyl styrene (ADAMS) monomers according to structure (I).

##STR00001##

wherein k is an integer from 1 to 3, preferably 2; wherein R.sub.1 is a methyl group or a phenyl group and R.sub.2 is a benzyl group, or wherein R.sub.1 and R.sub.2 are connected to form a moiety containing one 6-membered ring, with four carbons, bearing an O or NCH.sub.3 group at the 4-position of the 6-membered ring; wherein R, in structure (I), is hydrogen, a phenyl ring co-attached at two neighboring ring carbon positions with the phenyl ring shown so as to form a naphthalene assembly, a phenyl group attached at a single carbon of the phenyl ring shown, a C.sub.1-C.sub.4 hydrocarbyl group (such as a methyl group), a C.sub.1-C.sub.6 hydrocarbyl group containing 1 to 4 additional heteroatoms (such as O, N, S, P, Se, and combinations thereof). Also provided are methods of using such functional polymers in lubricating oil compositions.

The present application relates to the use of a lubricant composition comprising a base oil or a base oil mixture having a viscosity (BOV or base oil viscosity) of less than or equal to 4, for reducing the particulate emissions of an engine.

The present application relates to the use of a lubricant composition comprising a base oil or a mixture of base oils, for reducing the particulate emissions of an engine, in which said base oil or said mixture of base oils has a kinematic viscosity, measured at 100 C., of less than or equal to 4.5 mm.sup.2/s, and in which said lubricant composition has a viscosity at 150 C. and under constant shear of greater than or equal to 2.4 mPa.s.sup.1.

The present application relates to the use of a lubricant composition comprising a base oil or a base oil mixture having a viscosity (BOV or base oil viscosity) of less than or equal to 4, for reducing the particulate emissions of an engine.

The present application relates to the use of a lubricant composition comprising a base oil or a mixture of base oils, for reducing the particulate emissions of an engine, in which said base oil or said mixture of base oils has a kinematic viscosity, measured at 100 C., of less than or equal to 4.5 mm.sup.2/s, and in which said lubricant composition has a viscosity at 150 C. and under constant shear of greater than or equal to 2.4 mPa.s.sup.1.