Abstract: A process is provided for the preparation of a graft copolymer compatibilizer useful at low levels for blending with separately prepared olefin copolymers and polymethacrylate polymers to form a stable, concentrated, polymer blend. The polymer blend, as well as the compatibilizer, are useful lubricating oil additives concentrates which contain at least 80 weight percent polymethacrylate segments. The polymer blend may be further diluted with a hydrocarbon oil to form a lubricating fluid. The polymer blend offers the benefit of the thickening power of olefin copolymers, the low temperature viscosity characteristics of polymethacrylates, and is stable for prolonged periods without phase separation.

Abstract: Graft copolymers wherein the backbone polymer is a polymeric hydrocarbon such as ethylene/propylene copolymer and the grafted units are the residues of an addition copolymerizable monomer system comprising an unsaturated polycarboxylic acid or anhydride and at least one other addition monomer. Preferably, the monomer residues are post-reacted with an alcohol or an amino alcohol. The graft copolymers are prepared with a free radical initiator which is blended with the reactants at a temperature below the initiator decomposition temperature, followed by heating to the decomposition temperature. The graft copolymers impart combined detergent, viscosity index improvement and other useful properties to lubricating oils and hydrocarbon motor fuels.

Abstract: Graft copolymers wherein the backbone polymer is a polymeric hydrocarbon such as ethylene/propylene copolymer and the grafted units are the residues of a monomer system comprising maleic acid or anhydride and one or more other monomers copolymerizable therewith, the monomer system being post-reacted with a polyamine compound. The graft copolymers impart combined detergent, viscosity index improvement and other useful properties to lubricating oils and hydrocarbon motor fuels.

Abstract: Graft copolymers wherein the backbone polymer is a rubbery, oil soluble ethylene-propylene copolymer or ethylene-propylene diene modified terpolymer and the graft monomer is a C-vinylpyridine or N-vinylpyrrolidone impart dispersant properties to hydrocarbon fuels and combined viscosity index improvement and dispersant properties to lubricating oils for internal combustion engines. The graft copolymers are prepared by intimate admixture of backbone polymer, graft monomer and free radical initiator at a temperature below initiation temperature, followed by a temperature increase to or above initiation temperature, thus providing a product containing little or no byproduct.