The invention relates to novel crosslinkable copolymers which are obtainable by (a) copolymerizing at least one hydrophilic monomer having one ethylenically unsaturated double bond and at least one crosslinker comprising two ore more ethylenically unsaturated double bonds in the presence of a chain transfer agent having a functional group; and (b) reacting one or more functional group of the resulting copolymer with an organic compound having an ethylenically unsaturated group. The crosslinkable copolymers of the invent are especially useful for the manufacture of biomedical mouldings, for example ophthalmic mouldings such as in particular contact lenses.
