Abstract: Hydrocarbon compositions, including oligomers and polymers, for use in improving the thermo-oxidative stability and the dispersancy and viscosity index improvement (for high molecular weight) properties of fuels and lubricating oils are disclosed. These compositions are adducts of sulfur mono- and diimides having one of the following formulae: ##STR1## wherein R is a hydrocarbycontaining at least 18 carbon atoms, in which X.dbd. can be O.dbd., S.dbd., Y'--N.dbd., i is 0 or 1, --Y and Y'-- can be ##STR2## wherein R' is hydrocarbyl or hydrocarbyloxy, R" is hydrocarbyl, R'" and R"" are hydrocarbyloxy, and each of R', R", R'", and R"" is from from 1 to 20 carbon atoms.

Abstract: Oil soluble viscosity index improvers-dispersants exhibiting improved cold temperature viscometric properties, and Thickening Efficiencies and Shear Stability Indexes generally similar to conventional V.I.-dispersants, comprised of the reaction products of (i) ethylene copolymer, such as copolymer of ethylene and propylene, grafted with ethylenically unsaturated carboxylic acid moieties, preferably maleic acid or anhydride moieties; (ii) polyamine having two or more primary amino groups or polyol; (iii) an amount effective to provide a V.I. improver-dispersant exhibiting improved cold temperature viscometric properties of a high functionality long chain hydrocarbyl substituted dicarboxylic acid material such as alkenyl succinic anhydride, preferably polybutene succinic anhydride, having a functionality of at least 1.2, preferably at least about 1.3, and more preferably at least 1.