A (per)fluoropolyether polymer [polymer] comprising at least one (per)fluoropolyoxyalkylene chain [chain (R pf)] having two chain ends, wherein at least one of said chain ends bears at least one group of formula -B- t, wherein: t is an integer equal to or higher than 2, more preferably from 2 to 5, even more preferably from 2 to 3; B is a group complying with the following formula (B-I): wherein R1, R2 and R5, identical or different each other, are a linear or cyclic aliphatic group comprising 6 carbon atoms, optionally substituted with one or more linear or branched alkyl group having from 1 to 3 carbon atoms, or a 6-membered aromatic group, optionally substituted with one or more linear or branched alkyl group having from 1 to 3 carbon atoms, R3 and R4 are each hydrogen atom or together they form a group of formula -C(=O)-, n is an integer from 1 to 4, preferably from 1 to 2, symbol (*) indicates the bond to said chain (R pf), and each symbol (§) indicates the bond to said moiety E; and E is a moiety of formula (E-I): (E-I) -[OCH(CH 3)CH 2] z -R U wherein z is in an integer from 1 to 15, (Ru) is an unsaturated moiety selected in the group consisting of: (R U -I) -O-C(=O)-CR H =CH 2 (R U -II) -O-C(=O)-NH-CO-CR H =CH 2 wherein R H is H or a linear or branched C 1 -C 6 alkyl group; more preferably H or a linear or branched C 1 -C 3 alkyl group. t is an integer equal to or higher than 2, more preferably from 2 to 5, even more preferably from 2 to 3; B is a group complying with the following formula (B-I): wherein R1, R2 and R5, identical or different each other, are a linear or cyclic aliphatic group comprising 6 carbon atoms, optionally substituted with one or more linear or branched alkyl group having from 1 to 3 carbon atoms, or a 6-membered aromatic group, optionally substituted with one or more linear or branched alkyl group having from 1 to 3 carbon atoms, R3 and R4 are each hydrogen atom or together they form a group of formula -C(=O)-, n is an integer from 1 to 4, preferably from 1 to 2, symbol (*) indicates the bond to said chain (R pf), and each symbol (§) indicates the bond to said moiety E; and E is a moiety of formula (E-I): (E-I) -[OCH(CH 3)CH 2] z -R U wherein z is in an integer from 1 to 15, (Ru) is an unsaturated moiety selected in the group consisting of: (R U -I) -O-C(=O)-CR H =CH 2 (R U -II) -O-C(=O)-NH-CO-CR H =CH 2 wherein R H is H or a linear or branched C 1 -C 6 alkyl group; more preferably H or a linear or branched C 1 -C 3 alkyl group. R1, R2 and R5, identical or different each other, are a linear or cyclic aliphatic group comprising 6 carbon atoms, optionally substituted with one or more linear or branched alkyl group having from 1 to 3 carbon atoms, or a 6-membered aromatic group, optionally substituted with one or more linear or branched alkyl group having from 1 to 3 carbon atoms, R3 and R4 are each hydrogen atom or together they form a group of formula -C(=O)-, n is an integer from 1 to 4, preferably from 1 to 2, symbol (*) indicates the bond to said chain (R pf), and each symbol (§) indicates the bond to said moiety E; and E is a moiety of formula (E-I): (E-I) -[OCH(CH 3)CH 2] z -R U wherein z is in an integer from 1 to 15, (Ru) is an unsaturated moiety selected in the group consisting of: (R U -I) -O-C(=O)-CR H =CH 2 (R U -II) -O-C(=O)-NH-CO-CR H =CH 2 wherein R H is H or a linear or branched C 1 -C 6 alkyl group; more preferably H or a linear or branched C 1 -C 3 alkyl group. z is in an integer from 1 to 15, (Ru) is an unsaturated moiety selected in the group consisting of: (R U -I) -O-C(=O)-CR H =CH 2 (R U -II) -O-C(=O)-NH-CO-CR H =CH 2 wherein R H is H or a linear or branched C 1 -C 6 alkyl group; more preferably H or a linear or branched C 1 -C 3 alkyl group.