Abstract
In this study, groundnut shell powder (GSP) was used for the reinforcement of recycled polypropylene (recycled PP). The GSP consisting of two-particle sizes viz (0-250 m and 250-420 m) was partly treated with sodium hydroxide at room temperature and the GSP both treated and untreated were compressed and compounded with recycled PP to produce GSP-recycled PP composites. For comparison, recycled PP was equally produced as a control sample. The effects of GSP addition and sodium hydroxide treatment on recycled PP were investigated through the mechanical testing of the developed composites. The mechanical properties (tensile strength, hardness, and toughness) of the composites were evaluated and the tensile strength of both treated and untreated GSP-recycled PP composites is higher than the recycled PP and the treated GSP of particle size 0-250 m having the highest tensile strength at 25 wt% GSP in recycled PP matrix. The hardness of the recycled PP increases with increasing content of GSP while the toughness decreases with increasing concentration of GSP in the recycled PP matrix. The water uptake of the GSP-recycled PP composites was equally studied, and the results revealed that the treated GSP-recycled PP composites has lower rate of water absorption as compared to untreated GSP-recycled PP composites Thermal stability and crystallinity of the composites and monolithic recycled PP were investigated, and it was discovered that the thermal stability and crystallinity of the polymer were enhanced with GSP addition. Morphological characterization of the selected samples through a scanning electron microscope (SEM) and x-ray diffraction (XRD) were equally done to validate the mechanical performance of the composites. Finally, biodegradability study on the composites and the control sample was conducted and it was found out that, the addition of GSP in both forms promotes the biodegradation of the recycled PP polymer. Such biodegradable GSP-recycled PP polymer composite materials are highly valuable for manufacturing food takeaway packages and some of the interior parts of the automobiles.