Novel Polycaprolactone Nanocomposites Containing Thymol of Interest in Antimicrobial Film and Coating Applications

It is well-known that the nanocomposites technology can significantly enhance, among others, the thermal, mechanical, and barrier properties of plastics. It is also known that most bioplastics, including the thermoplastic biopolymers, have lower than desired levels for certain properties which makes their use in certain packaging applications problematic. The combination of active technologies such as antimicrobials and nanotechnologies such as nanocomposites can synergistically lead to bioplastic formulations with balanced properties and functionalities for their implementation in packaging applications. The present work presents the development and characterization of novel nanocomposites of polycaprolactone with enhanced barrier properties and with controlled-release of the biocide natural extract thymol. The antimicrobial nanocomposites of biodegradable materials were prepared in solution by a casting method. The morphology of the biocomposites was visualized by transmission electron microscopy and by atomic force microscopy, the thermal properties were investigated by differential scanning calorimetry and the relative uptake (solubility) and kinetics (diffusion) of the released biocide were determined by Attenuated Total Reflection Fourier Transformed Infrared spectroscopy. Water, oxygen, and limonene barrier properties were also enhanced in the biocomposites.