Star-branched polymers and functional fluids prepared therefrom
AssigneeMobil Oil Corporation
InventorsWan-Li Liu, Frederick C. Loveless
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Abstract
Novel star-branched polymers in which the arms are each a polymer of an anionically polymerizable monomer consisting of monoethylenically unsaturated compounds comprising p-tert-butylstyrene (t-BS) coupled with a polyalkenyl coupling agent. Certain of the foregoing star-branched polymers, e.g., wherein the arms are a homopolymer of t-BS and the coupling agent is divinylbenzene (DVB), are useful as additives to functional fluids, particularly hydrocarbon lubricating oils, for the purpose of improving their viscometric properties.
Claims5
A star-branched polymer made by a process comprising contacting an anionically polymerizable monomer consisting of monoethylenically unsaturated monomers comprising at least 50 wt. % of p-tert-butylstyrene (t-BS) with an anionic polymerization catalyst to form living polymer anions and coupling said living polymer anions with a polyalkenyl coupling agent, said living polymer anions having a number average molecular wight (Mn) in the range of about 10,000 to 50,000.
Dependencies are inferred from the claim text.