Preparation and Performance Analysis of Slow-release Antimicrobial Films Containing Oregano Essential Oil-loaded Rice Straw Cellulose-based Halloysite Nanotubes

This study developed a slow-release antimicrobial films and examines their release kinetics. The substrates for film formation include rice straw cellulose (RSC), high-amylose corn starch (HACS), polyvinyl alcohol (PVA), and glycerin (GLY). Oregano essential oil (OEO) was loaded onto halloysite nanotubes (HNTs) to create slow-release antimicrobial films (HNT-OEO/HPRG) with varying HNT-OEO contents. Scanning electron microscopy (SEM), thermogravimetric analysis (TGA), and Fourier transform infrared spectroscopy (FTIR) confirm the strong compatibility between HNT-OEO and the substrate materials, attributed to hydrogen bonding. Performance testing demonstrated that the HNT-OEO₃/HPRG film containing 6% HNT-OEO, exhibited a tensile strength of 43.24 MPa, elongation at break of 102.33%, and water vapor transmission rate of 278.38 g/m²·24 h. By fitting the release data to zero-order, first-order, Higuchi, and Ritger-Peppas kinetic models and by conducting inhibition experiments, we determined that the release behavior of the HNT-OEO₃/HPRG membrane adheres to the first-order kinetic model (R²>0.95). Compared with the OEO/HPRG membrane, the HNT-OEO₃/HPRG membrane significantly extends the release time of OEO (P<0.05), resulting in a sustained bacteriostatic effect. This study combines experimental findings with theoretical analysis, providing valuable insights into the development of slow-release antimicrobial films utilizing plant essential oil-loaded HNTs and enhancing the potential applications of natural antimicrobial agents in packaging materials.