Dispersants and dispersant viscosity index improvers from selectively hydrogenated polymers

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:
• wherein R1—R6 are each hydrogen or a hydrocarbyl group, provided that at least one of R1—R6 is a hydrocarbyl group, provided that after polymerization, the unsaturation of the polymerized conjugated diene of formula (1) has the formula:
• wherein RI, RII, RIII and RIV are each hydrogen or a hydrocarbyl group, provided that either both RI and RII are hydrocarbyl groups or both RIII and RIV 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:
• wherein R7—R12 are each hydrogen or a hydrocarbyl group, provided that after polymerization, the unsaturation of the polymerized conjugated diene of formula (3) has the formula:
• wherein RV, RVI, RVII and RVIII are each hydrogen or a hydrocarbyl group, provided that one of RV or RVI is hydrogen, one of RVII or RVIII is hydrogen, and at least one of RV, RVI, RVII and RVIII 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;
• functionalizing said selectively hydrogenated copolymer to provide a functionalized copolymer having at least one polar functional group:
• and
• post treating the functionalized copolymer with a post-treating agent.

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:
• wherein R1—R6 are each hydrogen or a hydrocarbyl group, provided that at least one of R1—R6 is a hydrocarbyl group, provided that after polymerization, the unsaturation of the polymerized conjugated diene of formula (1) has the formula:
• wherein RI, RII, RIII and RIV are each hydrogen or a hydrocarbyl group, provided that either both RI and RII are hydrocarbyl groups or both RIII and RIV 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:
• wherein R7—R12 are each hydrogen or a hydrocarbyl group, provided that after polymerization, the unsaturation of the polymerized conjugated diene of formula (3) has the formula:
• wherein RV, RVI, RVII and RVIII are each hydrogen or a hydrocarbyl group, provided that one of RV or RVI is hydrogen, one of RVII or RVIII is hydrogen, and at least one of RV, RVI, RVII and RVIII 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;
• functionalizing said selectively hydrogenated copolymer to provide a functionalized copolymer having at least one polar functional group;
• and
• post treating the functionalized copolymer with a post-treating agent.