Lubricant grease compositions comprising polymeric diphenylamine antioxidants

A lubricating grease composition comprising a base oil;

• a water insoluble thickener;
• and
• from about 0.01 wt % to about 20 wt %, based on the total weight of the lubricating grease composition, of a polymer composition comprising repeat units of diphenylamine monomers of formula I
• wherein
• R is H, C1-C18 alkyl, C2-C18 alkenyl, C2-C18 alkynyl, —C(O)C1-C18 alkyl, —C(O)aryl and R1, R2, R3 and R4 are each independently H or a linear or branched C1-C18 alkyl, C1-C18 alkoxy, C1-C18 alkylamino, C1-C18 dialkylamino, C1-C18 alkylthio, C2-C18 alkenyl, C2-C18 alkynyl or C7-C21 aralkyl, and
• wherein the polymer composition comprises ≤70 wt % residual monomers of formula I.

A lubricating grease composition comprising

• a base oil;
• and
• from about 0.01 wt % to about 20 wt %, based on the total weight of the lubricating grease composition, of an antioxidant polymer composition comprising repeat units of diphenylamine monomers of formula I
• wherein
• R is H, C1-C18 alkyl, C2-C18 alkenyl, C2-C18 alkynyl, —C(O)C1-C18 alkyl, —C(O)aryl and R1, R2, R3 and R4 are each independently H or a linear or branched C1-C18 alkyl, C1-C18 alkoxy, C1-C18 alkylamino, C1-C18 dialkylamino, C1-C18 alkylthio, C2-C18 alkenyl, C2-C18 alkynyl or C7-C21 aralkyl and
• wherein
• the number average molecular weight (Mn) of the polymer composition is from about 350 g/mol to about 5000 g/mol.