One aspect of the invention relates to a biocompatible, covalently cross-linked, polymer that is obtained by reacting an electrophilically activated polyoxazoline (EL-POX) with a nucleophilic cross-linking agent, said electrophilically activated POX comprising m electrophilic groups and said nucleophilic cross-linking agent comprising n nucleophilic groups, wherein the m electrophilic groups are capable of reaction with the n nucleophilic groups to form covalent bonds wherein m≥2, n≥2 and m+n ≥5 wherein at least one of the m electrophilic groups is a pendant electrophilic group and/or wherein m≥3 and wherein the EL-POX comprises an excess amount of electrophilic groups relative to the amount of nucleophilic groups contained in the nucleophilic cross-linking agent. The invention further relates to biocompatible medical products comprising such a cross-linked POX-polymer. Also provided is a kit for producing a biocompatible, cross-linked POX-polymer. The invention further provides a tissue adhesive medical product comprising at least 1% by weight of dry matter of EL-POX, said EL-POX comprising at least 2 electrophilic groups, including at least one pendant electrophilic group. The polymers according to the invention have excellent implant and/or sealing characteristics.Un aspect de linvention concerne un polymère biocompatible réticulé de manière covalente, obtenu par mise en réaction dune polyoxazoline activée de manière électrophile (EL-POX) et dun agent de réticulation nucléophile. La POX activée de manière électrophile comprend m groupes électrophiles, et lagent de réticulation nucléophile comporte n groupes nucléophiles. Les m groupes électrophiles peuvent réagir avec les n groupes nucléophiles pour former des liaisons covalentes, où m≥2, n≥2 et m+n ≥5. Au moins lun des m groupes électrophiles est un groupe électrophile latéral et/ou m≥3. LEL-POX comprend une quantité de groupes électrophiles supérieure à la quantité de groupes nucléophiles contenus dans lagent d
