Dispersants and dispersant viscosity index improvers from selectively hydrogenated polymers: free radically initiated direct grafting reaction products

A method of modifying the dispersancy or viscometric properties of a fluid, comprising:

• admixing with a fluid an amount of dispersant substance sufficient to provide a dispersant-modified fluid having modified dispersant or viscometric properties;
• wherein said dispersant substance comprises:
• a copolymer of a first conjugated diene and a second conjugated diene, wherein:
• said first conjugated diene comprises at least one relatively more substituted conjugated diene having at least five carbon atoms and the formula:
• ##STR20## wherein R.sup.1 -R.sup.6 are each hydrogen or a hydrocarbyl group, provided that at least one of R.sup.1 -R.sup.6 is a hydrocarbyl group, provided that after polymerization, the unsaturation of the polymerized conjugated diene of formula (1) has the formula:
• ##STR21## wherein R.sup.I, R.sup.II, R.sup.III and R.sup.IV are each hydrogen or a hydrocarbyl group, provided that either both R.sup.I and R.sup.II are hydrocarbyl groups or both R.sup.III and R.sup.IV are hydrocarbyl groups;
• and
• said second conjugated diene comprises at least one relatively less substituted conjugated diene different from the first conjugated diene and having at least four carbon atoms and the formula:
• ##STR22## wherein R.sup.7 -R.sup.12 are each hydrogen or a hydrocarbyl group, provided that after polymerization, the unsaturation of the polymerized conjugated diene of formula (3) has the formula:
• ##STR23## wherein R.sup.V, R.sup.VI, R.sup.VII and R.sup.VIII are each hydrogen or a hydrocarbyl group, provided that one of R.sup.V or R.sup.VI is hydrogen, one of R.sup.VII or R.sup.VIII is hydrogen, and at least one of R.sup.V, R.sup.VI, R.sup.VII and R.sup.VIII is a hydrocarbyl group;
• and
• wherein said copolymer has been functionalized by a method comprising:
• selectively hydrogenating said copolymer to provide a selectively hydrogenated copolymer;
• and
• functionalizing said selectively hydrogenated copolymer by free radically initiated grafting of heteroatom-containing olefins to provide a functionalized copolymer having at least one polar functional group.

A dispersant-modified fluid having modified dispersancy or viscometric properties comprising:

• a fluid;
• and
• a dispersant substance comprising;
• a copolymer of a first conjugated diene and a second conjugated diene, wherein:
• said first conjugated diene comprises at least one relatively more substituted conjugated diene having at least five carbon atoms and the formula:
• ##STR24## wherein R.sup.1 -R.sup.6 are each hydrogen or a hydrocarbyl group, provided that at least one of R.sup.1 -R.sup.6 is a hydrocarbyl group, provided that after polymerization, the unsaturation of the polymerized conjugated diene of formula (1) has the formula:
• ##STR25## wherein R.sup.I, R.sup.II, R.sup.III and R.sup.IV are each hydrogen or a hydrocarbyl group, provided that either both R.sup.I and R.sup.II are hydrocarbyl groups or both R.sup.III and R.sup.IV are hydrocarbyl groups;
• and
• said second conjugated diene comprises at least one relatively less substituted conjugated diene different from the first conjugated diene and having at least four carbon atoms and the formula:
• ##STR26## wherein R.sup.7 -R.sup.12 are each hydrogen or a hydrocarbyl group, provided that after polymerization, the unsaturation of the polymerized conjugated diene of formula (3) has the formula:
• ##STR27## wherein R.sup.V, R.sup.VI, R.sup.VII and R.sup.VIII are each hydrogen or a hydrocarbyl group, provided that one of R.sup.V or R.sup.VI is hydrogen, one of R.sup.VII or R.sup.VIII is hydrogen, and at least one of R.sup.V, R.sup.VI, R.sup.VII and R.sup.VIII is a hydrocarbyl group;
• and
• wherein said copolymer has been functionalized by a method comprising:
• selectively hydrogenating said copolymer to provide a selectively hydrogenated copolymer;
• and
• functionalizing said selectively hydrogenated copolymer by free radically initiated grafting of heteroatom-containing olefins to provide a functionalized copolymer having at least one polar functional group.