Polymeric-inorganic particles useful as lubricant additives

A polymeric-inorganic nanoparticle, comprising one inorganic nanoparticle covalently bonded to one or more polymers, each polymer comprising:

• a) units derived from at least one compound of formula (I):
• and
• b) units derived from at least one alkyl (meth)acrylate, wherein the alkyl group of the alkyl (meth)acrylate comprises from 1 to 40 carbon atoms,
• wherein:
• at least two units a) of each polymer are covalently bonded to the inorganic nanoparticle;
• R is H or CH3, where 0≤h≤2;
• Si(A)h(X)3-h is a silane functional group;
• A is a branched or unbranched C1 to C4 alkyl residue;
• B a branched or unbranched, aliphatic, aromatic or mixed aliphatic-aromatic C1 to C30 carbon-based group;
• X is selected from H, Cl or a group OY, wherein Y is H or a C1 to C30 branched or unbranched alkyl-, alkenyl-, aryl-, or aralkyl- group, branched or unbranched C2 to C30 alkylether-group or branched or unbranched C2 to C30 alkylpolyether-group or a mixture thereof.