Non-silicone urea-based adhesives are disclosed which are prepared by the polymerization of reactive oligomers with the general formula X—B—X, where X is an ethylenically unsaturated group and B is a unit free of silicone and containing urea groups. The reactive oligomers can be prepared from polyamines through chain extension reactions using diaryl carbonates followed by capping reactions. Adhesive articles, including optical adhesive articles may be prepared using the disclosed non-silicone urea-based adhesives.