Abstract:
This research deals with the development of smart packaging based on polypropylene-1 wt% clay nanocomposites incorporated with silver nanoparticles at different contents (5, 10, 15, and 20 wt% in the clay). The masterbatch of nanocomposites was first prepared by a twin-screw extruder with plasma-assisted process and then further mixed with PP to reach the nanocomposites with 1 wt% of clay, followed by a blown film extrusion to a clear film for packaging application. The effects of silver nanoparticles on crystal structure, mechanical behavior, thermal properties, and gas permeability of the nanocomposite films were evaluated. The results revealed that the intercalated and partly exfoliated nanocomposite films were obtained. The presence of clay and silver nanoparticles had an adverse effect on the tensile strength and the percentage of elongation at break. However, an increase in the Young's modulus was obtained. This is deduced from the higher stiffness of the nanocomposite films. Furthermore, the existence of clay and these nanoparticles resulted in an increment in the percentage of crystallinity of the nanocomposite films, regarding the nucleating effect arised from the nanoparticles. The nanocomposite films also had higher thermal stability compared to neat PP film. With regard to an antifungal activity, the release of silver nanoparticles enabled the nanocomposite films to against Colletotrichum gloeosporioides. Only 5 wt% of silver nanoparticles in the clay presented the exfoliation structure of layered silicates in the matrix and concurrently manifested the potential in anti-anthracnose activity. In addition to the aforementioned films, this work also fabricated the indicator film for fish freshness by tapping the potential of a natural dye from the sappan wood mixed with ethylene vinyl acetate. In conclusion, the assembly of both films could afford to be a smart packaging for chilled fish storage. In particular, with potential use of this smart packaging, this film is capable of being applied for other categorizes of agricultural products, such as Nam-Dok-Mai mango, and Hom-Thong banana, etc.
