Comparative Study of Irradiated and Non-Irradiated Recycled Polypropylene/Peanut Shell Powder Composites under the Effects of Natural Weathering Degradation

Abstract

The properties of irradiated and non-irradiated recycled polypropylene (RPP)/peanut shell powder (PSP) composites were investigated relative to the effects of 6 months exposure to natural weathering. RPP/PSP composites were prepared by melt-mixing and compression molding with 0 to 40 wt.% PSP loading. The fabricated composites were then irradiated using a 2.0 MeV electron beam accelerator at a fixed dose of 20 kGy. The properties of non-irradiated and irradiated composites after exposure to natural weathering were compared and characterized by tensile properties, scanning electron microscopy (SEM), carbonyl indices (CI), differential scanning calorimetry (DSC), and weight loss analysis. The results in tensile strength and tensile modulus of irradiated RPP/PSP composites increased, while elongation at break decreased. The thermal stability of irradiated composites was also improved compared with non-irradiated composites. Pores and fungus penetration were observed from the SEM morphology, while an increase in carbonyl index and weight loss of both composites were evidenced that degradation occurred. The overall results indicated that the irradiated RPP/PSP composites were more resistant to natural weathering degradation than the non-irradiated RPP/PSP composites.