Abstract: Poly（vinyl alcohol）/starch composite films were prepared by means of a casting film?forming method using tapioca starch and poly（vinyl alcohol） as basic film-forming materials and sodium lauryl sulfonate as a surfactant. Based on single factor experiments， the effects of the amounts of tapioca starch， poly（vinyl alcohol） and surfactant sodium lauryl sulfonate， molding processing temperature， and molding processing time on the mechanic performance of the composite films were investigated. The three factors of tapioca starch dosage， sodium lauryl sulfonate dosage， and molding processing time were optimized through orthogonal experiments to determine the optimal processing conditions of the composite films. The soil degradation and fresh?keeping properties of the as?prepared composite films were studied. The results indicated that the composite films achieved optimal mechanical properties at a poly（vinyl alcohol） amount of 1 g， a tapioca starch amount of 0.7 g， a sodium lauryl sulfonate amount of 0.5 g， a molding processing temperature of 80 ℃， and a molding processing time of 65 min. The composite films exhibited high elongation at break of 262.58 % and ultimate tensile strength of 24.63 MPa. The developed composite films obtained good degradability. There was no evidence of mold growth for the composite films after storage for 8 h， indicating a certain preservation effect on fresh flowers.

Key words: poly（vinyl alcohol） composite membrane, tapioca starch, sodium dodecyl sulfonate, biodegradation, preservation