Morphological, Mechanical, and Antimicrobial Properties of PBAT/Poly(methyl methacrylate-co-maleic anhydride)–SiO2 Composite Films for Food Packaging Applications

A poly(methyl methacrylate-co-maleic anhydride) P(MMA-co-MA) copolymer was synthesized via radical polymerization. The synthesized P(MMA-co-MA) copolymer was identified by 1H- and 13C-nuclear magnetic resonance spectroscopy (1H-NMR), (13C-NMR), Fourier-transform infrared (FTIR) spectroscopy, X-ray diffraction (XRD), scanning electron microscopy (SEM), and transmission electron microscopy (TEM). The poly(butylene adipate-co-terephthalate) (PBAT)/P(MMA-co-MA)-SiO2 composites were developed using a solution-casting method. The PBAT to P(MMA-co-MA) weight ratio was kept at 70:30, while the weight percentage of SiO2 nanoparticles (NPs) was varied from 0.0 to 5.0 wt.%. SiO2 was used for PBAT/P(MMA-co-MA) to solve the compatibility between PBAT and the P(MMA-co-MA) matrix. The PBAT/P(MMA-co-MA)-SiO2 composites were characterized by studied FTIR spectroscopy, XRD, SEM, and TEM. A comparison of the composite film PBAT/P(MMA-co-MA)-SiO2 (PBMS-3) with the virgin PBAT and P(MMA-co-MA) film revealed its good tensile strength (19.81 MPa). The WVTR and OTR for the PBAT/P(MMA-co-MA)-SiO2 composites were much smaller than for PBAT/P(MMA-co-MA). The PBAT/P(MMA-co-MA)-SiO2 WVTR and OTR values of the composites were 318.9 ± 2.0 (cc m-2 per 24 h) and 26.3 ± 2.5 (g m-2 per 24 h). The hydrophobicity of the PBAT/P(MMA-co-MA) blend and PBAT/P(MMA-co-MA)-SiO2 composites was strengthened by the introduction of SiO2, as measured by the water contact angle. The PBAT/P(MMA-co-MA)-SiO2 composite films showed excellent antimicrobial activity against the food-pathogenic bacteria E. coli and S. aureus from the area of inhibition. Overall, the improved packaging characteristics, such as flexibility, tensile strength, low O2 and H2O transmission rate, and good antimicrobial activities, give the PBAT/P(MMA-co-MA)-SiO2 composite film potential for use in food packaging applications.