Search Results (6)

The present study assessed the potential of engaging response surface analysis in the experimental design, modeling, and optimization of the strength performance of aluminum-7075 green composite. The design of the experiment was carried out via the Box–Behnken method and the independent variables are rice husk ash (RHA) at 3–12 wt.%, glass powder (GP) at 2–10 wt.%, and stirring temperature (ST) at 600–800 °C. Responses examined are yield, ultimate tensile, flexural, and impact strengths, as well as microhardness and compressive strength. ANOVA analysis revealed that the input factors had consequential contributions to each response, eventually presenting regression models statistically fit to represent the experimental data, further affirmed by the diagnostic plots. The result of the optimization envisaged an optimal combination at 7.2% RHA, 6.2 GP, and 695 °C with a desirability of 0.910. A comparison between the predicted values for the responses and the values of the validation experiment revealed an error of <5% for each response. Consequently, the models are certified adequate for response predictions at 95% confidence, and the optimum combination is adequate for the design of the composite. Full article

The use of ashes derived from various waste sources as supplements to synthesized ceramic reinforcement in metal matrices has been established. However, studies involving a combination of particulates from three different sources are rare. In a bid to further knowledge in this aspect of research and develop a green aluminium composite for automobile applications, the present investigation studied the implication of adding palm kernel shell ash (PKA), rice husk ash (RHA), and waste steel particles (STP) to the morphology and strength behaviour of Al-6061-T6 alloy. The experimental design was undertaken via the Box–Behnken design (BBD) of the response surface method. A 4% STP at a constant dose was mixed with PKA and RHA at varying proportions and stirring temperatures according to the BBD. The experimental outcome revealed that the responses were greatly influenced by microstructural evolution. From the surface plots, 2–4% RHA and PKA enhanced tensile and flexural strengths, while 4–6% led to a decline in strength. Meanwhile, 2–6% of the particles are favourable to the enhancement of tensile and compressive strengths and moduli. Temperatures between 700 and 800 °C favored response improvement, whereas temperatures between 800 and 900 °C were detrimental to responses. Developed regression models for the responses were validated to be good representations of the experimental outcomes. The optimum mix was obtained at 4.81% PKA, 5.41% RHA, and a stirring temperature of 803 °C. The validation experiment conducted portrayed reliable responses with <5% deviation from the predicted values, thereby certifying the models to be statistically fit for future predictions. Full article

This study investigates the physical and mechanical properties of short Entada mannii- glass fiber polypropylene hybrid composites. The polymeric hybrid composite was produced by combining different ratios of Entada mannii fiber (EMF)/glass fiber (GF) using the compression molding technique. The tensile properties, compressive strength, impact strength and hardness were evaluated while the fracture surface morphology was examined using the scanning electron microscope (SEM). It further evaluates the moisture absorption and percentage void content of the developed composites. The experimental results show that tensile, compressive, impact and hardness properties of all the hybrid composites were significantly improved as compared with single reinforced composites. Specifically, hybrid composites (EMF/GF5) revealed an overall tensile strength of 41%, hardness of 51% and compressive strength of 47% relative to single reinforced composites, which can be ascribed to enhanced fiber–matrix bonding. The chemical treatment enhanced the EMF fiber surface and promoted good adhesion with the polypropylene (PP) matrix. Moisture absorption properties revealed that the addition of EMF/GF reduces the amount of moisture intake of the hybrid composites attributed to good cementing of the fiber–matrix interface. Morphological analysis revealed that single reinforced composites (EMF1 and GF2) were characterized by fiber pullout and deposition of voids in the composite as compared with the hybrid composites. Full article

The incorporation of materials that were formally regarded as agricultural wastes into polymeric matrix has drawn the attention of many researchers in recent years. This research focused on reinforcing high-density polyethylene (HDPE) matrix with treated jute fiber (JF)/oil palm pressed fruit fibers (OPPFF) at varying weight proportions. JF and OPPFF were cut to 2.5 mm length and were chemically treated thereafter with 1 M and 1.5 M sodium hydroxide solution respectively. The composites were produced using the compression molding technique. The morphological characterization of the fibers and composites for untreated and treated samples was studied with the aid of a scanning electron microscope (SEM). Tensile and flexural properties of the produced composite samples were also determined. From the result, the surface morphology of the fiber after treatment showed that there was obvious exposure of the fiber surface and removal of impurities as this influenced the microstructure of the composites and in turn the tensile and flexural properties. Hence, it was observed that 20 wt.% treated jute fiber addition shows the most significant enhancements in terms of tensile and flexural properties. The study exposed the effect of surface modification of JF/OPPF hybridization on HDPE matrix composite. Full article

This work was on the comparative evaluation of the property effects obtainable when acetylation is applied to parts of selected agro fibers that are obtainable within common localities. The fibers were subjected to different concentrations of acetylation treatment at ambient temperature for 3 h. The physico-chemical, morphological, and tensile properties of the fibers were examined after the treatment. It was discovered from the results that the procedures variedly influenced the constituents of the fibers, their resulting tensile properties as well as their post-acetylation treatment surface morphology. The proportion of crystalline cellulose in the starting fibers greatly influenced their post treatment composition, behaviour and properties. The results show that plantain fibers had the highest aspect ratios, followed by banana fibers with values of about 1000 and 417, respectively. These fibers exhibited the least density and are thus potential plant fibers for composite development. Banana fiber had the least density of about 1.38 g/cm³ while that of DombeyaBuettneri fiber possessed the highest value of 1.5 g/cm³. There was significant enhancement in the hemicellulose content of Combretum Racemosum, while the lignin content of the plantain fibers was highly reduced. The treatment favoured the enhancement of the tensile properties in Combretum Racemosum fibers, which had enhanced tensile strength and strain at all compositions of the treatment. Optimum tensile strength and strain values of 155 MPa and 0.046, respectively, are achieved at 4% composition. Dombeya Buettneri fibers showed the highest ultimate tensile strength among the plant fibers in the untreated condition, which was gradually decreased as the concentration of the reagents was increased. Overall, 4% acetylation treatment is optimum for tensile properties’ enhancement for most of the natural fibers evaluated. Full article

In this study, wear resistance and some selected physical properties of pawpaw–glass fiber hybrid reinforced epoxy composites were investigated. Two different layers of pawpaw stem—linear and network structures—were extracted and chemically modified. Hybrid reinforced composites were developed comparatively from the two fiber structures and glass fiber using hand lay-up in an open mold production process. The wear resistance was studied via the use of a Taber Abrasion Tester while selected physical properties were also investigated. The influence of the fiber structure on the properties examined revealed that network structured pawpaw fiber was the best as reinforcement compared to the linearly structured fiber. The addition of these vegetable fibers to epoxy resin brought about improved thermal conductivity and increased the curing rate while the wear resistance of the corresponding developed composites were enhanced by 3 wt% and 15 wt% of fibers from linear and network pawpaw fibers. It was noticed that linearly structured pawpaw fiber had its best result at 3 wt% while network structured pawpaw fiber had its best result at 15 wt%. Full article