Effect of electron beam radiation on POLY(LACTIC acid) biocomposites reinforced with waste tea powder

Abstract

Waste tea powder (WTP)/poly(lactic acid) (PLA) biocomposites were prepared using a Brabender Plastograph mixer and RAY-RAN injection moulding machine. The effect of WTP loadings (0–50 wt %) and NaOH mercerisation on the properties of WTP/PLA biocomposites were investigated. The WTP/PLA biocomposites were then subjected to electron beam irradiation to elucidate the biocomposites' radiation compatibility. The infrared spectrum of untreated and treated WTP were obtained using Fourier Transform Infrared Spectroscopy (FTIR). The results show mercerisation of WTP facilitated its dispersion, as observed under scanning electron microscopy (SEM). The biocomposite's mechanical and thermal properties were obtained using a tensile test, Izod impact test, and thermogravimetric analysis (TGA). A decreasing trend for both tensile and impact tests with increasing WTP loading regardless of NaOH mercerisation was observed. However, the tensile strength of the irradiated biocomposite samples was not significantly affected. Moreover, the thermal stability of the biocomposites was improved with mercerisation but not affected by the irradiation process. Biocomposites with 50% mercerised WTP loading showed the highest equilibrium water absorption. Studies reveal that WTP/PLA biocomposites show radiation stability at low dosages of electron beam irradiation (20 and 40 kGy), which is beneficial for food and medical packaging applications. At higher doses, it appears that the WTP/PLA biocomposites undergo predominantly radiation-induced degradation.