Biodegradable Nanocomposites with Antibacterial Silica Nanoparticles and Their Food Packaging Applications

Plastics such as polyethylene terephthalate (PET), polyvinylchloride (PVC), polyethylene (PE), polypropylene (PP) are extensively used for food packaging materials due to their desirable packaging performance, and easy processability. However, the increased use of plastics has become a serious environmental problem, and as a result, research on eco-friendly biodegradable plastics is drawing attention. In particular, in the food packaging field, biodegradable plastics require antibacterial properties for long-term storage of food in addition to mechanical properties for packaging. Therefore, in this study, a biodegradable nanocomposite with biodegradability and antibacterial performance was developed. Specifically, quaternary ammonium functionalized core-shell silica nanoparticles(QAS-SiO2 NPs) were used to impart antibacterial effects to biodegradable plastics. Firstly, QAS-SiO2 NPs were synthesized through ammonia-catalyst hydrolysis and condensation of tetraethylorthosilicate(TEOS) and (octadecyldimethyl(3-triethoxy silylpropyl) ammonium chloride) (ODDMAC). QAS-SiO2 NPs had an excellent antibacterial effect by quaternary ammonium functional groups. The amount of quaternary ammonium functional groups was quantitatively analyzed through TGA and elemental analysis. Secondly, the biodegradable nanocomposite is prepared through blending with QAS-SiO2 NPs and various biodegradable plastics, such as polylactic Acid (PLA) and polyhydroxyalkanoates (PHAs). These nanocomposites had desired packaging performance, biodegradability, and excellent antibacterial properties. Additionally, the antibacterial properties increased as the amount of quaternary ammonium functional groups on silica particles increased. Finally, this study using antibacterial nanoparticles is expected to be used not only in food packaging but also in various applications such as textiles and healthcare devices.