Methods for making biomaterials for use as a tissue sealant, kits containing precursors for forming the biomaterials, and the resulting biomaterials are described herein. The biomaterials are formed from a composition comprising at least a first and a second precursor molecule, wherein: i) the first precursor molecule is a poly(ethylene glycol) based polymer having x nucleophilic groups selected from the group consisting of thiol or amino groups, wherein x is equal to 2 or greater than 2, preferably 3, 4, 5, 6, 7 or 8； ii) the second precursor molecule is of the general formula: €ƒ€ƒ€ƒ€ƒ€ƒ€ƒ€ƒ€ƒ A-[(C 3 H 6 O) n -(C 2 H 4 O) m -B] i wherein m and n are integers from 1 to 200 i is greater than 2, preferably 3, 4, 5, 6, 7 or 8 A is a branch point B is a conjugated unsaturated group.
