Abstract: In this paper， poly （butylene adipate-co-terephthalate） （PBAT）/poly （lactic acid） （PLA）/dioctyl terephthalate （DOTP）/nano-ZnO composites were prepared by using a solvent casting method. Nano-zinc oxide was surface modified with stearic acid， and the effects of particle sizes and surface modification of nano-ZnO on the mechanical， thermal， hydrophobic， extraction and antibacterial properties of the composite films were investigated. The results indicated that the extraction resistance of the composite films was improved due to the replacement of the hydroxyl polar group on the surface of nano-ZnO with stearic acid. The entanglement of the long chain alkyl of stearic acid with polymer chains improved the compatibility of modified nano-ZnO with PBAT. The thermal properties of the composite films decreased with a decrease in the particle size of nano-ZnO but an increase in the addition amount of modified nano-ZnO. However， their extraction resistance increased. Moreover， the tensile strength of the composite films increased up to 13.8 MPa， and their hydrophobic properties increased up to a contact angle of 110 °. The antibacterial properties of the composite films were also enhanced with an increase in the antibacterial circle.

Key words: poly（butylene adipate-co-terephthalate）, zinc oxide, composite film, antibacterial property