Mechanical, physical and biodegradability performances of treated and untreated groundnut shell powder recycled polypropylene composites

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 μm and 250-420 μm) 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 μm 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.

Plastic/fiber composite using recycled polypropylene and fibers from Sorghum halepense L.

“…Large fiber clusters formed as a result of aggregation tendencies of fiber flours with small particle sizes (0 to 420 μm) mingled with polymer chains and supported crystallinity development. Although cellulose is a good nucleic agent for polymer crystallization, particle size, fiber distribution, and interfacial adhesion of the fiber to the polymer matrix significantly affect the crystallinity values (Usman et al 2020).…”

Bio‐Polypropylene and Polypropylene‐based Biocomposites: Solutions for a Sustainable Future

“…The rest of the composites contain 25% loading of GSP, where sample names with “U” and “T” means GSP untreated and treated with sodium hydroxide, and sample names with “420” and “250” means samples were fabricated with GSP of particle sizes of 0–450 μm and 0–250 μm respectively. Reproduced with permission [111] . Copyright 2020 IOP Publishing Ltd.…”

“…Also addition of CPO was found to increase the water absorption in the composites, which weakens the polymer structure but in turn promote microbial activity and thus biodegradation. Usman et al [111] on the other hand studied the biodegradation effects of rPP with groundnut shell powder (GSP) at two different particle sizes of 0-250 μm and 0-450 μm, and two conditions of GSP with and without sodium hydroxide treatment. Biodegradation studies of the composites were conducted on a potato dextrose agar media inoculated with Aspergillus niger at 25 °C over 21 days.…”

Synthesis of Hybrid Composites from Bio-Based Fillers: Chicken Feather, Groundnut Shell, Sawdust

“…The tensile strength ranged from 1.88 MPa to 9.56 MPa while impact strength varied from 0.3 kJ/m 2 to 1.6 kJ/m 2 [4]. Tensile strength, hardness, and toughness of the composites were also evaluated for the reinforcement of recycled polypropylene (recycled PP) and groundnut shell powder consisting of two-particle sizes (0-250 μm and 250-420 μm) [5]. Unsaturated polyester/potash feldspar (UP/PF) composites containing various ratios of wood sawdust fiber (2, 4, and 6 phr) show that wood sawdust (WSD) fiber efficiently improves the mechanical properties of UP/PF/WSD composites and 6% of wood sawdust shows better tensile strength [6].…”