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In this research, the composites of maize cob (MC)/unsaturated polyester resin (UPR) and composites of jute fiber (JF)/unsaturated polyester resin (UPR) were prepared using the hand lay-up technique. The study employed 5%, 10%, 15%, and 20% filler loadings for the preparation of the MC/UPR and JF/UPR composites. The composites were subsequently characterized to examine their mechanical and physical properties. The results reveal that the increase in percentage filler loading decreases the tensile strength, impact strength, flexural strength, hardness, and density, whereas the water absorption increases at higher filler loading. This observation could be ascribed to clumping, voids, and agglomeration formed during composites preparation for both fillers. The MC/UPR composite exhibited better flexural resistance of 31.41 Mpa to 28.88 Mpa compared to 25.72 Mpa to 22.14 Mpa for JF/UPR due to the excellent dispersion of MC, larger surface area, and intermolecular interactions between the particulate MC filler/matrix. The MC/UPR composites also exhibited higher density compared to the JF/UPR due to the larger surface area and reduced voids in the structure. Overall, the study demonstrated that the valorization of maize cob and jute fibers into composite materials is a sustainable and environmental approach to waste disposal and management.

This article investigated the utilization of the Sammaz-14 variety of maize (Zea mays spp.) cobs for the isolation of nanocelluloses through chemical and mechanical methods. The extracted nanocelluloses were characterized by particle size analysis (PSA), thermogravimetric analysis (TGA), Fourier transform infrared (FTIR) spectroscopy, and X-ray diffraction (XRD). Morphological analysis was performed through Field Emission Scanning Electron Microscopy (FESEM) and Atomic Force Microscopy (AFM), whereas energy disperse X-ray (EDX) was used to determine the elemental composition. The isolated maize cob nanocrystals (MC-NC) and maize cob nanofibres (MC-NF) were obtained in nanoscale, as shown by PSA. Thermal analysis showed that MC-NF is more thermally stable when compared to MC-NC. FTIR revealed identical spectrums for MC-NC and MC-NF with minor deviation from the MC-UT due to the elimination of the 1700 cm−1 peak. Morphological studies showed MC-NC and MC-NF have needlelike structures, while the untreated maize cob (MC-UT) is plain due to the amorphous portion. MC-NC has higher crystallinity of 78% compared to 61% for MC-NF and 40% for MC-UT.

AbstractReprocessing of synthetic fiber-reinforced thermoplastics for reuse in the design of structural components applications is important owing to their non-biodegradability. This study evaluates the effect of reprocessing on the service life properties of in-house polypropylene wastes reinforced with E-glass fiber. Composite materials containing 10 mm length glass fiber (GF) and recycled polypropylene were manufactured with 10 wt% GF and subjected to five reprocessing cycles via extrusion and compression molding under similar conditions. Properties such as mechanical, melt flow index (MFI), thermogravimetric analysis (TGA), Fourier transform infrared (FTIR) spectroscopy, x-ray diffraction (XRD), and scanning electron microscopy (SEM) analysis were used to analyze the effect of reprocessing on the composites. The results obtained revealed that the composites’ properties diminished with successive reprocessing. The thermal study showed reductions in the thermal stabilities with a drop in onset degradation temperature from 338.07 to 245.15 °C after five runs, indicating an increase in the polymer chain molecular movement and less rigidity due to shorter chains provided by X-ray diffraction analysis with reduced peak intensities, average crystallite sizes, and degree of crystallinities but no destruction of the main functional groups was observed with the spectral studies. An increase in the MFI (6 g/10–17.88 g/10 min) indicated the possible loss of complex viscosity and damage in molecular weight for the reprocessed matrix. Reinforced in-house PP plastics can, therefore, be reprocessed twice only for the same product except with the addition of either virgin PP or other materials to compensate for the lost properties and help manufacturers save costs.