Advanced Materials Research Vol. 879

Abstract: Fiber Metal laminates, FML, is a combination of metal with fiber/resin laminates and it is a well-known application in composite laminates due to its dimension stability and properties consistency. Generally, the strength of these laminates systems is much depends on the mechanical interlocking mechanism between the metal surface and the composite laminates. Therefore, surface treatment is needed to enhance the laminates strength. In this research, aluminum plates with different surface roughness were laminated with carbon-fiber/epoxy laminates. The strength of these hybrid systems was then characterized to study the effect of surface roughness on the interfacial strength. It shows that the higher surface roughness will result in better interfacial interaction between the metal surface and the fiber laminates.

Abstract: Cyclohexane is mainly produced by catalytic hydrogenation of benzene, and the separation of unreacted benzene is very important process. However, the separation of benzene and cyclohexane mixture is one of the difficult separation processes in petrochemical industry. Presently, extractive distillation is commercially used to separate benzene and cyclohexane using molecular solvents. However, the current process suffers from process complexity and high-energy consumption. In this work, new ionic liquid, 1-propanenitrile-3-butylimidazolium dicyanamide was synthesized and applied for separation benzene and cyclohexane mixture. Some of the thermophysical properties of the ionic liquid were measured. The vapour- liquid equilibrium and relative volatility of the components were determined. The ionic liquid breaks the azeotropic mixture and increased the relative volatility of cyclohexane to benzene.

Abstract: In PIM process, the molding stage is a critical step for the fabrication of sound parts without cracks and distortions. So, this step requires specific rheological behavior. Rheological analysis can be made to quantify the stability of the PIM feedstock during molding process. In this study, an experimental rheological study has been performed to evaluate the influence of palm stearin on the rheological behavior and stability of Inconel 718 powder injection molding (PIM) feedstock. The effects of shear rate and temperature were investigated via capillary rheometer method. The viscosity and shear rate of the feedstock were measured at various range of temperature and shear rate across the L/D = 1 capillary rheometer. The results show that the formulation binder system PSPE 7030 is the best feedstock to be injection molded because it has moderate value of flow sensitivity index, lower value for flow activation energy and higher value for mold ability index. Besides that, the increasing of PS content in the binder system has found reduce viscosity and value of flow activation energy and increase value of mold ability index of feedstock.

Abstract: Photochromism behaviors of a spiropyran dye namely 5-bromo-8-methoxy-6-nitro BIPS (BNM) has been investigated in the present of papain as anti-oxidant at different H⁺ ions conditions. BNM has been dissolved and diluted in ethanol (EtOH) to a concentration of 1.0 x 10^-5M. The hydrochloric acid (HCL) was used to alter the acidity of the solution to be pH2 and pH7. The fine dispersed transparent solutions were exposed to UV light at 365nm for 5s and the absorption spectra were measured using UV-Vis spectrometer. Upon UV light irradiation, BNM exhibits photochromic behaviors by displaying coloration changes from transparent to light purplish with maximum absorbance spectrum, λ_max at 552nm with and without present of papain in both acidic (pH2) and neutral (pH7) conditions. It was found that incorporation of papain in both different pH conditions slightly decreased the intensities of absorbance spectrum for BNM photo-transformation activities. However, detection in time drive mode at 522nm with 5s UV irradiation showed that the addition of papain stabilize and prolongs the absorbance intensity. Incorporation of anti-oxidant molecules is significant in order to obtain long-life activities of the spiropyran in the photo-reversible activity of open-form merocyanine state to closed-form spiro state. This study reveals that the photo-transformation stability of BNM molecules is increased with addition of papain in neutral condition that acts as anti-oxidant agent towards the BNM photo-reversible process.

Abstract: This paper presents the attempt to manufacture metallic implant using medical grade 316L stainless steel alloy powder by MIM process. The powder with the median particle size of 15 μm and a binder consisting of palm stearin and poly ethylene were mixed at 160°C using a sigma-blade mixer for one hour to prepare the feedstock of the test bar. The rheological properties of the feedstock was tested using capillary rheometer. The test bar was injection moulded using vertical injection moulding machine with the nozzle temperature of 200°C. Prior to sintering, the specimens were debound using a combination of solvent extraction and thermal pyrolysis method. The specimens were then sintered under vacuum at the temperature between 1300oC to 1360oC. The properties of the sintered bar such as physical appearance and densities were presented and discussed. The biocompatibility including toxicity properties of the implant also been presented. The results showed that physical and mechanical properties of the sintered sample complied with the international standard

Abstract: Metal injection molding (MIM) is capable of mass producing intricately shaped components. In recent years, this technology has been adopted in the electronic, computer, aerospace and medical industries. Titanium alloy (Ti6Al4V) is difficult to process because of its reactive nature and primarily because of problems with carbon and oxygen impurities. Even at low concentration, these interstitials can severely degrade the mechanical properties of titanium and its alloys. The main objective of this study is to develop a sintering condition that would eliminate problems with carbon and oxygen contamination and facilitate binder removal, thus enhance the sintering properties. Ti6Al4V with binder formulation consists of polyethylene (PE), paraffin wax (PW), stearic acid (SA) and palm oil derivatives; palm stearin (PS) were mixed homogeneously and injected to produce green compacts. The binders then were removed and sintering of injection molded material was conducted up to 1200 °C in vacuum atmosphere. The parts sintered at 1150 °C for 8 h exhibited among the highest tensile strength of 921.1 MPa while the elongation, density, porosity and hardness was 6.4%, 4.358 g/cm³, 3.16% and 320 HV respectively. This is the advantageous of additional argon flow during debinding , whereas the physical and mechanical properties were improved due to the impurity gas in argon that had strong effects on the aspects of densification and elimination of pores that turn the powder into a dense solid Ti6Al4V.

Abstract: Biocomposite from bamboo powder was fabricated by compression molding technique. The objective of this study was to investigate the mechanical properties of bamboo compounded with epoxy with different ratio. Tensile and flexural tests were done to characterize its mechanical properties. It was observed that the strength of bamboo-polyester was increased with increasing amount of bamboo powder. The tensile and flexural strength shows the highest value at 25 wt.% bamboo. However, the impact test shows the maximum value at 20 wt.% bamboo powder. These results exhibit the bamboo-polyester can be a good candidate to be used in many engineering applications

Abstract: Organic dyes namely 1,3,3-trimethylindolino-naphtospirooxazine (TINS) and 3,3-diphenyl-3H-napthol [2,1-pyran DNP) were used in studies of photochromic transformation in ethanol solution. The samples were exposed to UV light ranging from 5, 10 and 15s respectively. TINS absorbs UV light at 613nm for multiple exposure time. The absorption initiated the opening of oxazine spirostructure with formation of open merocyanine species. Irradiation of DNP with UV at 5, 10 and 15s absorbs at 413nm with formation of opening cyclicstucture of naphthopyran, namely allenyl-naphtol. The intensity peaks of TINS and DNP were increased with increasing the period of irradiation time. TINS and DNP dyes exhibit normal photochromic in the polar protic solvent by displaying color changes form transparent to color blue and light orange under exposed UV light. The photochromic activity of these compounds is due to the reversible light-induced cleavage of the C-O bond between the heterocyclic oxygen atom and the quaternary carbon.

Abstract: Powder injection molding (PIM) is a powder metallurgy process currently used for the production of complicated and near net shape parts of high performance materials [. This technique basically combines the advantages of plastic injection molding and the versatility of the conventional powder metallurgy technique. The process overcomes the shape limitation of powder compaction, the cost of machining, the productivity limits of isostatic pressing and slip casting, and the defect and tolerance limitations of conventional casting [1, 2, . According to German and Bose [, the technology of metal injection molding (MIM) is more complicated than that of the plastic injection molding, which arises from the need to remove the binder and to densify and strengthen the part. The process composed of four sequential steps: mixing of the powder and organic binder, injection molding, debinding where all binders are removed and sintering [1, 2, 3, 4]. If it necessary, secondary operations such as heat treatments after sintering can be performed [1, 2, 3, 4, .

Abstract: The blends of thermoplastic polyurethane (TPU) with natural rubber (NR) at four different blends ratios were prepared via melt blending, with addition of liquid natural rubber (LNR) as compatibilizer. The effect of blend ratio and temperature on the tensile properties and swelling ratio was studied. The addition of NR and LNR into TPU produces a decrease of tensile strength. The swelling ratio increased with the increasing of NR content in the blends. The temperatures of blending also give effects to tensile properties and swelling behavior.