Engineering Headway Vol. 15

Abstract: Nowadays, the use of rubber products such as tyres, bearings, shoe soles, hoses, and cables are increasing due to its high strain to failure. However, the indestructible cross-linking of sulphur or peroxide chains in vulcanized rubber could complicate the biodegradation, reprocessing, and recycling of rubber products. Due to these crucial problems, the increasing number of rubber-based products worldwide will lead to environmental hazards. An alternative strategy to address this problem is to give elastomers the ability to self-heal, thus promoting their reusability. Zinc diacrylate (ZDA) salt was used as a self-healing agent in NR. The ionic interaction of the self-healing process between natural rubber (NR) and ZDA were investigated, and successful grafting was demonstrated by FTIR analysis. The results showed that NR with 10 phr of ZDA had the highest tensile strength and elongation at break, which was also proved by microscopic images. The image showed no visible gap between the fractured contact surface of NR indicating an efficient self-healing mechanism. Therefore, this study has proven the potential of ZDA as a self-healing agent to NR compound and is expected to pave the way for environmentally friendly rubber products.

Abstract: Synthetic foam will negatively impact the environment and living beings. To solve this issue, synthetic materials may be substituted with more eco-friendly materials, such as foam derived from bamboo. The structure of bamboo and the substances inside make it highly useful for various applications. This research produced a biodegradable foam from the difference in weight fraction of cellulose derived from bamboo. The Kraft pulping process has been used to remove lignin and to get cellulose from bamboo (Bambusa vulgaris). The foam substance was produced by combining starch and cellulose derived from bamboo with chemical ingredients such as sodium chloride, sodium dodecyl sulfate, glycerin, and sodium hydrogen carbonate. Cellulose bio-foam (CBF) derived from bamboo were characterized by Scanning Electron Microscopy (SEM) and Energy-Dispersive X-ray (EDX). Scanning electron microscopy is a powerful technique that allows for evaluating surface morphological changes. When SEM is combined with the EDX technique, it can provide valuable input in determining the distribution of various elements on the surface. The results of SEM - EDX spectra have shown that essential elements like Carbon (C), Oxygen (O), Sodium (Na) and Chlorine (Cl) were present in the cellulose bio foam (CBF). These findings indicate that cellulose bio foams (CBF) derived from bamboo have the potential to be used in a wide range of commercial applications in substitution of synthetic foam materials.

Abstract: Efforts to reduce the usage of imported raw materials in the ceramic industry have encouraged usage of local calcite minerals for production of refractory ceramic products. Corundum-mullite ceramics as refractory products were prepared by using clay, alumina and calcite mineral (CaO) via powder pressing method. The effect of CaO addition from 2.9 to 6.5 wt.% (R1, R2 & R3) on the mechanical strengths such as bulk density, apparent porosity, firing shrinkage and compressive strength were systematically studied as well as the reheat shrinkage and crystallinity of mullite ceramic bodies. The results indicated that the sintering process was prevented by the formation of anorthite phase at higher CaO content. The bulk density increased continuously as the CaO content was increased from 2.9 to 6.5 wt.%, while the apparent porosity and water absorption decreased with the increment of CaO content especially at temperature 1400 °C. On the other hand, addition of small amount of CaO have improved compressive strength of the ceramic body due to reduction in porosity and increase of crystalline phase. Addition of CaO content higher than 4.8 wt.%, would result in increment of crystallinity of the body due to formation of anorthite phase. It was observed that the R1 body (2.9 wt.% CaO) has the lowest reheat shrinkage percentage compared to other bodies and has complied with the Japanese Industrial Standard of mullite refractory product which is lower than 0.2% shrinkage percentage at 1300°C in the furnace for 8 hours.

Abstract: The effect of small additions of niobium pentoxide (Nb₂O₅) from 0 to 0.7 wt% on the zirconia toughened alumina (ZTA) ceramics sintered at 1600 °C was studied. Based on the results, the small addition of Nb₂O₅ was discovered to be able to significantly influence on phase, microstructure, and mechanical properties of ZTA ceramics. The presence of the secondary phase of Nb₂Zr₆O₁₇ as a square-shaped particle is confirmed by SEM and FESEM-EDX up to 0.5 weight percent (wt.%) of Nb₂O₅ additions. The addition of 0.3 wt.% resulted in the highest Vickers hardness value of 1500 Vickers hardness (HV). However, it was found that adding Nb₂O₅ more than 0.3 wt% causes ZTA's hardness and indentation fracture resistance (K_IFR) values to decline from 1500 HV to 1438 HV and 4.88 MPa.√m to 4.18 MPa.√m, respectively. Additionally, it was found that when the amount of Nb₂O₅ added increased, the value for bulk density climbed while porosity reduced.

Abstract: Barium halide activated with Eu is a typical phosphor material used in imaging plates for computed radiography applications. In this study, BaBrX: Eu (X = Cl, I) was synthesized via the hydrothermal technique. The aim of this study is to further explore the feasibility of the hydrothermal method for synthesizing phosphor materials. This was determined by studying the effect of Eu addition on the structural and optical properties of BaBrX (X = Cl, I). X-ray diffraction (XRD) was employed to determine the crystallinity of the prepared samples, while optical properties were observed using photoluminescence (PL) spectroscopy. The sharp, narrow, and high-intensity peaks of XRD diffractogram indicated that all samples exhibited good crystallinity. The addition of the Eu element as an activator resulted in a blue-shift with broad and higher intensity of the main emission peak for several samples. This study demonstrates that the addition of the Eu element to the host materials has altered the structural properties and improved the optical properties of the prepared samples, significantly demonstrating the feasibility of the hydrothermal method for synthesizing phosphor materials.

Abstract: In this study, we report the functionalization of imidazolium-based ionic liquids (ImIL) onto mesoporous silica SBA-15 nanomaterial with a larger surface area of 737.96 m²/g and an interpore distance of 10.68 nm. Imidazolium-based ionic liquids, 1-(3-triethoxysilylpropyl)-methylimidazolium chloride was functionalized with concentration of 1.0, 2.0, 4.0, 6.0, 8.0 and 10.0 mmol onto SBA-15 via a sol-gel method to obtain xImIL-SBA-15 nanocomposites. Small-angle X-ray scattering (SAXS), N₂ adsorption/desorption analysis and field emission scanning electron microscopy (FESEM) were used to characterize the ImIL-SBA-15 nanocomposites. SAXS patterns of ImIL-SBA-15 nanocomposites possessed (1 0 0), (1 1 0) and (2 0 0) diffractions respectively, which indicated that the well-ordered hexagonal mesostructure of SBA-15 support remained intact after functionalization of ImIL. The total surface area, total pore volume and BJH pore size distribution of all ImIL-SBA-15 nanocomposites decreasing with the increasing amount of ImIL from 393.27 to 354.39 m²/g which indicated that the pore channel and/or surface of SBA-15 were occupied by ImIL without significant reduction of the quality. It was found that the grafted amount of ImIL on SBA-15 nanocomposites increased from 0.60 to 0.97 mmol/g when amount of ImIL content in the mixture was increased from 1.0 to 10.0 mmol. FESEM micrographs showed a similar pattern as SBA-15 indicating that the mesoporous hexagonal structure of SBA-15 was still retained. Thus, it can be concluded that xImIL-SBA-15 nanocomposites was successfully synthesized by functionalization of ImIL onto mesoporous silica SBA-15.

Abstract: Due to tighter restrictions on the use of hazardous lead-bearing solder alloys, lead-free solder research has seen significant growth in recent years. The most common SAC alloys have emerged as viable candidates for the substitution of conventional Sn-Pb alloys among the representative lead-free solders (Sn-Cu, Sn-Bi, Sn-Zn, Sn-In, Sn-Ag, and Sn-Ag-Cu (SAC)). These alloys have limited use in contemporary microelectronic packaging devices due to various worries about the existence of brittle intermetallic compounds (IMCs) like Ag₃Sn and Cu₆Sn₅ in these materials. Over the years, numerous lead-free solder alloy alternatives with nanoparticle reinforcement have been proposed as an alternative to limit the growth of IMCs and enhance solder joint durability. This paper details the development of lead-free solders with selected fillers and reinforcements to date. The thermal cyclic test method was also discussed as one of the alternatives for reliability test techniques to be explored in future studies on this topic. In conclusion, fillers and reinforcements are also essential for enhancing interconnection’s heat cycle efficiency. Exploring various fillers and reinforcements that can be used to advance lead-free solder technology with thermal cyclic methods will open more investigation opportunities for lead-free solders.

Abstract: The use of sandwich plates has gained significant popularity in the construction and machinery industries due to their exceptional stiffness-to-mass and strength-to-mass ratios. Among various structural types, I-core sandwich plates (T-joints) and corrugated-core sandwich plates (K-joints) are widely utilized. The welding method employed significantly impacts joint performance and overall structural characteristics. This review paper examines recent research on these commonly used sandwich plates and their joint performance, encompassing preparation methods, performance evaluation, structure optimization, and overall research progress. Furthermore, the influence of different preparation methods on the overall performance of sandwich plates is also addressed.

Abstract: There are abundant silica sand resources in Malaysia, however many have not yet been fully discovered. The primary component used in the production of glass is silica sand. The objective of this research was to determine whether local silica sand might be used to make coloured glass. The chemical composition and mineralogy of silica sand were determined using X-ray fluorescence (XRF) and X-ray diffraction (XRD), respectively. The physical properties such as particle size distribution were determined by using a mechanical shaker whereas grain morphology was identified by using a digital microscope. Additional equally significant properties such as moisture content, clay content, pH value and the specific gravity of silica sand were also measured by using standard laboratory testing method. The obtained results were compared to Malaysian Standard MS 701:2017, the standard specification for the production of coloured glass. From XRF analysis, the silica sand contained silicon dioxide at a concentration of 97.84%, alumina at 0.56%, iron oxide at 0.12% as well as several other oxides at around 1.5%. XRD diffractogram also revealed that quartz is a major constituent having the highest peaks at about 26.7° with an intensity of 13,7786. More than 95% of the particle sizes of the silica sand are in the size range from 150 µm to 1000 µm and in the category of fine sand and coarse sand. The grain shape was determined to be angular, and the silica sand had a moisture content of 2.54%, a clay content of 7.80%, a pH value of 5.93, and a specific gravity of 2.63. Based on the chemical and physical properties, it appears that this particular silica sand satisfies the standard requirements for coloured glass production.