Polymer blends are disclosed that comprise one or more polybutadiene homopolymers or copolymers having at least one functionality capable of entering into condensation reactions; one or more polyethylene terephthalate homopolymers or copolymers obtained using a catalyst system comprising aluminum atoms and one or more alkaline earth metal atoms, alkali metal atoms, or alkali compound residues, optionally obtained by a melt-phase polymerization process; and one or more transition metal atoms. The blends are useful for packaging, and exhibit improved oxygen-scavenging activity compared with blends made using many conventional polyethylene terephthalate polymers prepared with conventional catalyst systems.