Abstract: Improved adhesives useful for the manufacture of composite structures by lamination, extrusion and coextrusion processes are provided. The compositions of the invention utilize ethylene copolymers having a network structure and exhibiting unique melt elasticity characteristics in combination with modified polyolefins containing acid or acid derivative functionality and, optionally, elastomeric polymers. Composite structures wherein the adhesives are adhered to one or more substrates and, particularly composite structures comprising metal or barrier resin layers with one or a plurality of crosslinked or uncrosslinked polyethylene resin layers, are also described.