A novel macromer or mixture thereof is described herein, comprising benzoyl isocyanate terminal moieties and at least two residues of a water-soluble polymer having a molecular weight ranging from 80 to 10,000 adjacent to the carbonyl group of the benzoyl isocyanate moieties, thereby forming at least two ester linkages in the macromer or mixture thereof. A method for making a polyisocyanate macromer is also described herein.