Preparation And Applications Of Starch/Poly (Butylene Adipate-co-terephthalate)/Silver Nanoparticles Composite Antimicrobial Films

In this study,hydroxypropyl cross-linked starch and poly(butylene adipate-co-terephthalate)(PBAT)were used as film-forming substrates.By adding nano-antimicrobial particles,degradable packaging films with good antimicrobial properties were prepared.The effect and mechanism of nano antimicrobial particles on the antimicrobial properties and physical properties of films were explored,the effects of gelatin on the antimicrobial properties and physical properties of degradable antimicrobial packaging films were explored.The application properties of the films were evaluated that provides technical support for the application and promotion of starch/PBAT antimicrobial film.The main findings are as follows:1.The effect of Ag NPs@Si O₂ loading on the properties of starch/PBAT films was studied.Scanning electron microscopy(SEM)showed that at the level of 1 wt%,the Ag NPs@Si O₂particles were uniformly distributed in the matrix,and the antimicrobial films loaded with 2-4wt%Ag NPs@Si O₂ exhibited different degrees of aggregation behavior.At the loading level of 1-2 wt%,the mechanical properties of the films were significantly improved,in which the tensile strength was up to 11.29 MPa and the elongation at break was up to 774.4%.In addition,the barrier performance of the films was significantly improved,and the affinity of the film for water was significantly reduced.When the loading amount was 1 wt%,the water contact angle(WCA)of the film was 95°.The overall antimicrobial performance of the films was dose-dependent that increased with the increase of the loading amount.The antimicrobial rate of the film loaded with 1wt%Ag NPs@Si O₂ was close to 90%.2.Antimicrobial composite films were prepared by compounding Ag NPs and Zn ONPs.The effect of Ag NPs and Zn ONPs compound ratio on the antimicrobial and physical properties of the films was studied under the ratio of the total nanoparticle loading of 1%.In terms of mechanical properties,the highest tensile strength of the composite film could reach13.01MPa,and the highest elongation at break of the composite film was 1003.57%.In terms of barrier properties,the water vapor barrier properties and oxygen barrier properties of the composite film were 10^-11g·m^-1·s^-1·Pa^-1 and 5.58×10^-14·cm~2·s^-1·Pa^-1,respectively.In terms of antimicrobial properties,the highest antimicrobial rate of the film after compounding could reach up to 98%.The starch/PBAT antimicrobial film showed excellent performance in reducing water loss,nutrient loss and inhibiting the growth of microorganisms in peach.3.Preparation and properties of gelatin/starch/PBAT ternary blend antimicrobial composite film was studied.The addition of gelatin reduced the mechanical properties of the films by 25%,mainly due to the poor compatibility between gelatin and PBAT.However,the addition of gelatin endowed the film with a certain antioxidant capacity and improved the antibacterial efficiency of the film.When the ratio of gelatin and starch was 1:1,the free radical scavenging rate could reach up to 25%.In the cheese packaging experiment,it could not only delay the oxidation of cheese,but also inhibit the reproduction of cheese microorganisms well.