(Co)polymer comprising the recurring unit of following formula I: in which - X is a divalent group of formula Ia or Ib below: in which • R is a trivalent hydrocarbon-based group selected from: a saturated or unsaturated, aliphatic or cycloaliphatic group, optionally interrupted with one or more heteroatoms, and optionally substituted with one or more functional or non-functional groups; an aromatic, alkylaromatic or arylaliphatic group, optionally interrupted with one or more heteroatoms, and optionally substituted with one or more functional or non-functional groups; • R' is a tetravalent hydrocarbon-based group selected from: a saturated or unsaturated, aliphatic or cycloaliphatic group, optionally interrupted with one or more heteroatoms, and optionally substituted with one or more functional or non-functional groups; an aromatic, alkylaromatic or arylaliphatic group, optionally interrupted with one or more heteroatoms, and optionally substituted with one or more functional or non-functional groups; - Y is: • a covalent bond, when X corresponds to formula Ib, • a divalent group of formula Ic or Id below, when X corresponds to formula Ia: with R as defined above. - X is a divalent group of formula Ia or Ib below: in which • R is a trivalent hydrocarbon-based group selected from: a saturated or unsaturated, aliphatic or cycloaliphatic group, optionally interrupted with one or more heteroatoms, and optionally substituted with one or more functional or non-functional groups; an aromatic, alkylaromatic or arylaliphatic group, optionally interrupted with one or more heteroatoms, and optionally substituted with one or more functional or non-functional groups; • R' is a tetravalent hydrocarbon-based group selected from: a saturated or unsaturated, aliphatic or cycloaliphatic group, optionally interrupted with one or more heteroatoms, and optionally substituted with one or more functional or non-functional groups; an aromatic, alkylaromatic or arylaliphatic group, optionally interrupted with one or more heteroatoms, and optionally substituted with one or more functional or non-functional groups; • R is a trivalent hydrocarbon-based group selected from: a saturated or unsaturated, aliphatic or cycloaliphatic group, optionally interrupted with one or more heteroatoms, and optionally substituted with one or more functional or non-functional groups; an aromatic, alkylaromatic or arylaliphatic group, optionally interrupted with one or more heteroatoms, and optionally substituted with one or more functional or non-functional groups; a saturated or unsaturated, aliphatic or cycloaliphatic group, optionally interrupted with one or more heteroatoms, and optionally substituted with one or more functional or non-functional groups; an aromatic, alkylaromatic or arylaliphatic group, optionally interrupted with one or more heteroatoms, and optionally substituted with one or more functional or non-functional groups; • R' is a tetravalent hydrocarbon-based group selected from: a saturated or unsaturated, aliphatic or cycloaliphatic group, optionally interrupted with one or more heteroatoms, and optionally substituted with one or more functional or non-functional groups; an aromatic, alkylaromatic or arylaliphatic group, optionally interrupted with one or more heteroatoms, and optionally substituted with one or more functional or non-functional groups; a saturated or unsaturated, aliphatic or cycloaliphatic group, optionally interrupted with one or more heteroatoms, and optionally substituted with one or more functional or non-functional groups; an aromatic, alkylaromatic or arylaliphatic group, optionally interrupted with one or more heteroatoms, and optionally substituted with one or more functional or non-functional groups; - Y is: • a covalent bond, when X corresponds to formula Ib, • a divalent group of formula Ic or Id below, when X corresponds to formula Ia: with R as defined above. • a covalent bond, when X corresponds to formula Ib, • a divalent group of formula Ic or Id below, when X corresponds to formula Ia: with R as defined above.