Polymers and lubricating compositions containing polymers

A polymer having the structure (I):

• wherein L is a linking group, R is a hydrocarbon group or a substituted-hydrocarbon group, and x is 2 or more;
• and wherein each {Q}
• contains a plurality of polymer blocks, each polymer block being composed of 3 or more monomer units, such that the moiety {Q}-L-{Q} has the structure {Pn . . . P2P1}-L-{P1P2 . . . Pn} where each Pn is an individual polymer block, the number of polymer blocks n in each {Q} being the same;
• wherein for each value of n the polymer blocks are identical;
• and wherein n is an integer of 2 or more, and wherein each polymer block is a homopolymer block and has the structure (II):
• wherein m is an integer of at least 3;
• wherein R1 is hydrogen or methyl;
• wherein X is a hydrocarbon group having from 1 to 50 carbon atoms, a substituted-hydrocarbon group having from 1 to 50 carbon atoms, COOR2, COSR2 or CONR2R3, OCOR2, CONHR2, CN, COSiR2R3 R4 or CI wherein R2, R3 and R4 are independently hydrogen, a hydrocarbon group having from 1 to 50 carbon atoms, or a substituted-hydrocarbon group having from 1 to 50 carbon atoms;
• and wherein in each block having structure (II), each R1 and each X and each m may be the same or different across polymer blocks.