Biobased as well as biodegradable materials were successfully developed through melt processing techniques from the blends of polyhydroxybutyrate-co-valerate (PHBV) and thermoplastic starch (TPS). The thermoplastic starch (TPS) was developed by blending of corn starch, glycerol, and a tough biodegradable polymer. The PHBV-TPS blends and their talc-filled biocomposites were successfully made into cast films. Further work explored the impact over time of three primary factors: ageing, leaching of the glycerol plasticizer, and the primary as well as the secondary crystallization of the PHBV component on the physical properties of the blends and their biocomposites. Mass transfer of moisture and oxygen through the developed films was correlated with the crystallinity and morphology of the materials using theoretical models. The developed materials were also exposed to aerobic composting conditions to study their biodegradable behaviors.