In this study, asbestos-free automotive brake pads produced from palm kernel fibers with epoxy-resin binder was evaluated. Resins varied in formulations and properties such as friction coefficient, wear rate, hardness test, porosity, noise level, temperature, specific gravity, stopping time, moisture effects, surface roughness, oil and water absorptions rates, and microstructure examination were investigated. Other basic engineering properties of mechanical overload, thermal deformation fading behaviour shear strength, cracking resistance, over-heat recovery, and effect on rotor disc, caliper pressure, pad grip effect and pad dusting effect were also investigated. The results obtained indicated that the wear rate, coefficient of friction, noise level, temperature, and stopping time of the produced brake pads increased as the speed increases. The results also show that porosity, hardness, moisture content, specific gravity, surface roughness, and oil and water absorption rates remained constant with increase in speed. The result of microstructure examination revealed that worm surfaces were characterized by abrasion wear where the asperities were ploughed thereby exposing the white region of palm kernel fibers, thus increasing the smoothness of the friction materials. Sample S6 with composition of 40% epoxy-resin, 10% palm wastes, 6% Al2O3, 29% graphite, and 15% calcium carbonate gave better properties. The result indicated that palm kernel fibers can be effectively used as a replacement for asbestos in brake pad production.

Evaluation of palm kernel fibers (PKFs) for production of asbestos-free automotive brake pads

Brake friction materials comprising of varying proportions of lapinus and wollastonite fibres are designed, fabricated and characterized for their chemical, physical, mechanical and tribological properties. Tribological performance evaluation in terms of performance coefficient of friction, friction–fade, friction–recovery, disc temperature rise (DTR) and wear is carried out on a Krauss machine following regulations laid down by Economic Commission of Europe (ECE R-90). The increase in wollastonite fibre led to an increase in density and hardness whereas void content, heat swelling, water absorption and compressibility increased with the increased in lapinus fibre. The performance coefficient of friction, friction–fade behaviour and friction–stability have been observed to be highly dependent on the fibre combination ratio i.e. coefficient of friction, fade and friction–stability follow a consistent decrease with a decrease in the lapinus fibre content, whereas the frictional fluctuations in terms of μ max  −  μ min have been observed to increase with a decrease in lapinus fibre content. However, with an increase in wollastonite fibre content in formulation mix, a higher wear resistance and recovery response is registered. The worn surface morphology has revealed topographical variations and their underlying role in controlling the friction and wear performance of such brake friction composites.

Assessment of braking performance of lapinus–wollastonite fibre reinforced friction composite materials

Sugar palm fibres are one of the natural fibres which have many features and need further study to understand their properties. The aim of this work is to investigate the flexural, compressive and impact properties of sugar palm fibres reinforced phenolic composites. Sugar palm fibres were used as a filler (particle size 150 μm) and with loading of 0, 10, 20, 30, and 40 vol.%. The fibres were treated by sea water and then fabricated into composites by hot press technique. Flexural, compressive, and impact tests were carried out as per ASTM D790, ASTM D695-08a, and ASTM D256 standards, respectively. Scanning electron microscopy (SEM) was used to investigate the morphology and the interfacial bonding of the fibres-matrix in composites. The results show that the mechanical properties of the composites improve with the incorporation of fibres. The composite of 30 vol.% particle loading exhibit optimum values which are 32.23 MPa, 61.66 MPa, and 4.12 kJ/m2 for flexural, compressive, and impact strength, respectively. This was because good compatibility of fibre-matrix bonding. Consequently, sugar palm fibre is one of the prospective fibres and could be used as a potential resource to reinforcement polymer composite.

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The Mechanical Performance of Sugar Palm Fibres (Ijuk) Reinforced Phenolic Composites

Aluminium (1xxx)/coconut shell micro particle (Al/CMP) composites have been developed using a compo cast technique. Coconut shells (CSs) were processed with the aid of mortar/pestle and disc grinder and then classified with a set of sieves vibrated with a sine shaker. The CMP additions increased from 2% to 10% at 2% interval. Microstructural/chemical composition analyses were carried out with the aid of scanning electron microscopes (ASPEX 3020) with attached energy dispersive X-ray spectroscopy. Phases were identified using an X-ray diffractometer (XRD). The tensile properties and mode of fracture were studied using Instron extensometer and Avery Denison Impact Testing Machine respectively. Results revealed 99.3% purity of aluminium matrix. The presence of new phases in the aluminium matrix is attributable to chemical interaction between Al and CMPs. The fine grained structure of Al/CMPs composites was confirmed by SEM and optical micrographs. The enhancement in the tensile properties is attributable to the presence of hard phases in the Al matrix and good interfacing bonding between Al matrix and CMP reinforcements. The cone and cup surface appearance with fibrous, dull, dimple and goose grain microstructure of the fracture surfaces of the composites is an indication of ductile fracture. Hence low cost metal matrix aluminium based composites have been developed.

Study of tensile properties, fractography and morphology of aluminium (1xxx)/coconut shell micro particle composites

Banana peel (BP) is an agrowaste produced in large volumes annually, especially by food-processing industries; however, its disposal is of significant concern. However, recent research suggests that BP is a valuable source of bioactive compounds, which can be converted into value-added products. This article reviews the conversion process of value-added products from BP and provides an outline on the chemical composition of BP and its possible applications. In addition, we also discuss the utilization of BP as a substrate to produce animal feed, biofertilizer, dietary fibers, clean energy, industrial enzymes, as well as its use in the synthesis of nanomaterials. Based on the research conducted so far, it is obvious that BP has a wide variety of applications, and thus, developing a biorefinery approach to adequately utilize BP will help realize its economic benefits to the fullest. Based on the valorization of BP, a scheme for BP biorefinery has been proposed. A material balance for BP biorefinery for 1-ton bone-dry BP is presented and our results show that 432 kg of protein or 170 kg of citric acid, 170 kg of pectin, 325 m3 of ethanol, and 220 m3 of methane can be produced.

Valorization of banana peel: a biorefinery approach

The use of asbestos fibre is being avoided due to its carcinogenic nature that might cause health risks. A new brake pad produced using banana peel waste to replace asbestos and Phenolic resin (phenol formaldehyde), as a binder was investigated. The resin was varying from 5 to 30 wt% with an interval of 5 wt%. Morphology, physical, mechanical and wear properties of the brake pad were studied. The results show that compressive strength, hardness and specific gravity of the produced samples were seen to be increasing with an increase in wt% of resin addition, while oil soak, water soak, wear rate and percentage charred decreased as the wt% of resin increased. Overall samples, containing 25 wt% in uncarbonized banana peels (BUNCp) and 30 wt% in carbonized (BCp) gave better properties. The result of this research indicates that banana peel particles can be effectively used as a replacement for asbestos in brake pad manufacture.

Eco-friendly asbestos free brake-pad: Using banana peels

Desulphurization of iron ore was carried out using an oxidant; powdered potassium chlorate (KClO3) of mass-input range (5-12g) and temperature range (500-800°C). The limit of desulphurization was evaluated considering the initial ore sulphur content and removed sulphur concentration. Investigation on the process analysis and mechanism of the desulphurization process revealed that oxygen gas from the decomposition of KClO3 interacted with sulphur through molecular combination within the Gas Evolution Temperature Range (GETR); 375-502°C. Sulphur transformation into vapour within this temperature range was observed to facilitate easy reaction with oxygen gas to form SO2, A limit of desulphurization; 92.22% was experimentally achieved following successful reduction of the initial ore sulphur content to 0.007 % using 12g of KClO3 at a treatment temperature of 800°C. A model was derived and used as a tool for empirical analysis of limit of desulphurization based on treatment temperature, mass-input of KClO3, sulphur loss-sulphur initial ratio. Deviational analysis indicates that the derived model gives best-fit process analysis with a deviation range of just 0.65–8.82%, from experimental results and invariably an operational confidence level range 91.18-99.35%. The deviation range corresponds to limit of desulphurization range: 31.4019-86.6128%, treatment temperature range: 600-800°C, KClO3 mass-input range: 7-12g and range of sulphur loss-sulphur initial ratio: 0.3444-0.5556. Hence, the derived model can exclusive, be significantly and viably operational within these process conditions.

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Empirical analysis of limit of desulphurization of iron ore based on multi-factorial process variables

Green corrosion inhibitors for steel and other metals in basic media: A mini-review

MS acceptability for nowadays structural construction is premised on its availability and low cost. However, due to MS poor corrosion resistance, most especially in acidic and alkaline environments, there have been increasing concerns about its use. The use of inhibitors, as proposed by different researchers, mitigates MS CR, thus reducing the economic losses experienced by all chief users of this alloy. In recent years, scientists have focused on green inhibitors obtained from plant, fruit and vegetable extracts, and essential oils. Besides being environmentally friendly, in terms of corrosion resistance, plant extracts are becoming increasingly important, due to their low cost and toxicity, and high availability. Additionally, they are rich in organic compounds with polar atoms, such as O, P, S and N, containing multiple bonds in their molecules, through which they can adsorb onto the metal surface, forming a protective film, by various adsorption isotherms. This paper provides a review on research works done so far on MS corrosion control by naturally occurring plant extracts as corrosion inhibitors, in both acidic and alkaline environments, where this alloy is mainly applied.

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C.I. Nwoye

Papers

Eco-friendly asbestos free brake-pad: Using banana peels

Empirical analysis of limit of desulphurization of iron ore based on multi-factorial process variables

Green corrosion inhibitors for steel and other metals in basic media: A mini-review

The Efficacy of Plant Inhibitors as Used against Structural Mild Steel Corrosion: A Review