Hydrogenated polymers with a radial structure having a core based on calixarenes and use thereof in lubricant compositions

Hydrogenated polymers with a radial structure having a core made up of calixarenes of the general formula I, to the core of which is linked a no. P of hydrogenated linear polymer segments selected from: - hydrogenated homopolymers or copolymers of conjugated dienes; or - hydrogenated copolymers of said conjugated dienes and monoalkenyl arenes, and - mixts. thereof said formula (I) in which: - R1, R2, R3 and R4 are independently selected from hydrogen; a group contg. carbon and hydrogen; a group also contg. heteroatoms in addn. to carbon and hydrogen; a group also contg. silicon in addn. to carbon, hydrogen and heteroatoms; - one of the two substituents R5 and R6 is hydrogen, while the other may be hydrogen or alkyl, with a no. of carbon atoms between 1 and 6, preferably Me and ethyl; - n is an integer in the range between 4 and 16.