Films of starch and poly(butylene adipate co-terephthalate) added of soybean oil (SO) and Tween 80

► This study characterized films made from blends of TPS/PBAT with SO and the Tween 80. ► The SO proved to be compatible with TPS/PBAT blends. ► Films added of SO improved the mechanical properties and microstructure. ► The addition of SO increased the chemical interaction among polymers. ► The SO improvised processability of films by balloon-blowing system.