Advanced Materials Research Vol. 748

Abstract: Reagent grade chemicals were used to explore glass formation ability and allocate the glass forming area for the glass system SiO₂-P₂O₅-Al₂O₃-MgO-Na₂O. FT-IR, DTA, DSC and TMA techniques were employed to characterize the obtained glasses. The multicomponent, mixed network glasses, in which AlPO₄ tetrahedral units are being incorporated into the network structure through substitution for pairs of SiO₄ tetrahedra, exhibit high durability, low thermal expansivity (at Al₂O₃/P₂O₅ ˃1), relatively high softening temperatures (at low P₂O₅ contents) and an increased thermal stability (poor tendency for crystallization). When heated at high temperatures and / or for long periods of time, and depending on their AlPO₄ content, together with the Al₂O₃/P₂O₅ ratio, the glasses crystallize through a multistage process involving reconstruction and depolymerization of the glasses network structure. The crystallization behavior of many different glasses was investigated, phases identified and characterized, through XRD, and SEM coupled with EDX and X-ray mapping together with optical microscopy. The powder ceramization route had to be used to achieve the devitrification of the glasses with high thermal stability. Berlinite, corundum, spinel, indialite and cordierite among others were the crystallizing phases when different glasses were heated for various times. Microporous materials made of some of these technically favorable minerals, and characterized by an interesting morphologies were obtained, through acid leaching of some of the glass-ceramics produced. It is believed that the glass system under investigation is a fertile one, the crystallization of some glasses within it, represents another fabrication route for obtaining glass-ceramics with specific crystalline phases, as well as microporous materials made of such phase. In both cases, packages of the most suitable properties are obtainable.

Abstract: In this research, rice husk and kenaf fiber were compounded with calcium carbonate (CaCO₃)/high density polyethylene (HDPE) composite.Different loadings of up to 30 parts of 50 mesh sizes of rice husk particulate and kenaf fiber were compounded using twin-screw extruder with fixed 30 parts of CaCO₃ fillerto produce hybrid composites of rice husk/CaCO₃/HDPE and kenaf/CaCO₃/HDPE.Compounded hybrid composites were prepared and tested for thermal properties. The thermal stability of the components was examined by thermogravimetricanalysis (TGA) and differential scanning calorimetric (DSC). The DSC results showed a slightly changes in melting temperature (T_m), crystallization temperature (T_c) and the degree of crystallinity (X_c) with addition of natural fiber. TGA indicates thermal stability of hybrid composite filled with kenaf or rice husk is better than unfilledCaCO₃/HDPE composite.

Abstract: The study about natural oils as processing aids in rubber was reported by several researchers for the past few years. The natural oils like rice bran oils, soybean oils, sunflower oils, vegetables oils and palm oils can be used as processing oils in rubber compounding [1-3]. These natural oils have been reported to have certain advantages compared to the petroleum based processing oils. In this study the potential of epoxidized palm oils (EPO) as additive and processing oils in carbon black filled styrene butadiene rubber was investigated. The main ingredients used were butadiene rubber (SBR), epoxidized palm oil (EPO) and carbon black. The vulcanized SBR rubber is then undergo several testing like swelling test, hardness and rebound resilience. An attempt was made to see whether the amount of EPO added to the SBR vulcanizates will affect the rebound resilience and swelling behaviour of the SBR vulcanizates. From this study, it was found that the compound contained higher EPO content tend to have lower rebound resilience, similar trend can be observed for hardness properties. While the crosslink density of the vulcanizates is decrease as the EPO content increases.

Abstract: New knowledge in findings potential usage of natural fiber as new material in composite technology has been increased gradually in years and these natural fiber materials are well known as competent material which can become an alternative material to the conventional and synthetic materials for suitable applications. In this research, Casuarina equisetifolia leaf was used as bio-based fiber and unsaturated polyester composite as the matrix due to its natural surface roughness without any chemical treatment. The aim of this study was to investigate the effect of various weight loadings of Casuarina equisetifolia in unsaturated polyester composites on the tensile test and morphological studies. The composite samples were fabricated by using press machine with mould dimension of (15x15x0.3) cm. From the tensile test results, tensile strength of the composite samples decreases with the increment of Casuarina equisetifolia by weight loadings. The surface morphology of the fractures composite samples was then analyzed using the microscopy technique (SEM) and found the evidence of fractured fiber breakage and voids content of the samples. Base on the result obtained, the tensile strength at 30% up to 50% weight loading of Casuarina equisetifolia has the potential to be used in non-structural applications.

Abstract: Fibre-metal-laminated composites that consist of aluminium and carbon fibre/epoxy was widely use in engineering fields such as in aerospace and civil application. An issue arise for this laminate systems is that aluminium surfaces must be treated to ensure the effectiveness of load transfer mechanism in the interfacial region. In this research, the effect of anodized layer on the aluminium surface towards strength of the carbon fibre-aluminium-laminated composites was studied. Aluminium 6061-T6 was anodized using phosphoric acid as electrolyte and different anodizing voltage to produce different surface morphology. The surface roughness and morphology were determined via Atomic Force Microscopy and its wettability was determined by Static Contact Angle. Then, anodized aluminium was laminated with carbon fibre/epoxy system via vacuum bagging techniques. It shows that the strength of laminated composite with anodized surface increases up to 26% compared to laminates without anodized surfaces. Furthermore, the failure mechanism of laminated composite with anodized surface resulted in partial adhered failure instead of adhesive failure. These show that anodized surfaces contributes to the effectiveness of load transfer mechanism in fibre-metal-laminates composites.

Abstract: The experimental results of epoxy resin modified by multiwall carbon nanotubes (MWCNTs) as two-phase nanocomposite are presented in the current paper. Effects of improved dispersion on reinforcement of the epoxy resins were investigated through three different prevalent conventional tests. Three various types of test specimens in four values of Mwcnt weight ratios, 0, 0.5, 1 and 2% to the GY6010 resin were fabricated according to corresponding ASTM standards by a novel technique. The static strength and stiffness tests led to the conclusion that the appropriate dispersion of Mwcnts into epoxy improves mechanical properties of two-phase nanocoposites.

Abstract: With the development of automotive industry, new high strength and high performance steel sheets are used more and more widely, which are the basis of weight reduction and safety improvement for automobiles. Taking examples of the design of car body, this paper focused on the remarkable effects of the application of AHSS in automobile lightweight, car safety and environment. It was also pointed out that the key topics will fall in the forming technique of AHSS and the applications of AHSS to new car body design to enhance automobile safety.

Abstract: In this paper, the mixed-mode cohesive fracture behavior of adhesively bonded joints was investigated based on numerical analysis. A modified version of Arcan specimen was employed to conduct a mixed-mode fracture test using a special loading device. A full range of mixed-mode loading conditions including pure mode-I and pure mode-II loading were created by ABAQUS software. This test method is a simple procedure, clamping/unclamping the specimens is easy to achieve and only one type of specimen is required to generate all loading conditions. Finite element analyses were carried out on specimens with different adherends in order to investigate deeply about cohesive fracture behavior of adhesively bonded joints.

Abstract: The purpose of this study is to evaluate the mould, which is made from mild steel and aluminium, and the effect of these moulds properties towards the quality of thermoplastics part. As for this research, two different types of mould material were fabricated by using Computer Numerical Controller (CNC) milling machine. These moulds were specifically design to produce a test sample which was an integral hinge made from Polypropylene. These moulds were tested practically by using Nissei-NP7-1F injection moulding unit. A set of parameter setting consisting of melt temperature, packaging pressure, injection time, packing time and mould temperature had been chosen to acquire the correlation between the mould materials and the part’s quality. Five tested samples were prepared for evaluation in terms of the material consumption, warpage, and shrinkage values. Results have been observed and analysed and it was found that in term of material consumption value, aluminium mould consumed 1.28 gram or 14% more polypropylene than mild steel. For warpage value, mild steel mould had the lowest value with only 0.08mm warpage. The third experiment showed that the lowest shrinkage was happened to be 0.01302, which was produced by mild steel mould. As the conclusion in this project, mild steel mould was selected as the desirable mould for producing integral hinges samples as compare with the aluminium mould.

Abstract: This research was conducted to evaluate the strength and folding performance of polypropylene packaging samples, when exposed to hot air and high humidity condition. Three types of polypropylene samples were chosen, which were flat plastic, plastic with hinges, and plastic film. All of these samples were tested for tensile strength; except plastic with hinges that received additional test to evaluate the folding endurance. American Society for Testing and Materials (ASTM) D638 standard was applied to analyze the mechanical strength of these plastics. This standard was used to determine the value of stress, strain, and Young’s modulus. Each sample was exposed to different temperature settings, which were 20°C, 25°C, and 30°C for high humidity condition and 60°C, 65°C, and 70°C for hot air condition. As for the folding endurance test, the hot air temperatures were selected at 60°C, 65°C and 70°C and for the high humidity condition, the range of relative humidity were set at 50%, 55% and 60%. Based on the tensile test results, the values of stress and Young’s modulus were higher at higher humidity as compared with the values under hot air condition. However the strain value was the opposite of the stress and Young’s modulus, whereby the values started to deceive under high humidity condition, but kept on increasing under hot air condition. In folding endurance test, it was confirmed that the hinge performed better under hot air environment than high humidity. As the relative humidity increases, the average number of folding decreased from 3.00x10⁶ to 2.89x10⁶ cycles. In the other hand, thevalue of folding numbers increased from 3.34x10⁶ to 3.37x10⁶, with increasing temperature. In conclusion, through this performance analysis, the outcomes can be applied to other packaging materials and appliances, which are related to high temperature and high humidity condition.