The oxygen permeability is an important parameter to be considered for packaging applications. However, while low oxygen permeability is needed for food packaging (ensuring good barrier properties), the packaging of medical products (sterile instruments, implants, biomaterials etc.) requires high permeability allowing penetration of gaseous sterilizing agent (ethylene oxide). High oxygen permeability of HDPE known as Tyvek is mainly originating from its apolar properties and microporosity of spun-bond fibres . Among other biodegradable polymers, PBAT has slightly better gas barrier properties . The PBS-DLS/PBAT 90/10 blend has shown relatively high oxygen permeability (Table ). Interestingly, the oxygen permeability of PBS-DLS copolymer is also high due to the presence of long aliphatic chains of fatty alcohol resulting in low crystallinity thus leading to less tortuous path of oxygen penetration through the amorphous phase. Likewise, it is contributing to high diffusion of amorphous regions and higher diffusivity of oxygen as the permeant. The introduction of PBAT further reduced the packaging density of the polymer chains thus leading to improved permeability of PBS-DLS/PBAT 90/10 blend.