Advanced Materials Research Vol. 576

Abstract: This study was conducted to produce green composite from kenaf with better thermal properties. Kenaf fibre was successfully prepared by chemi-mechanical method. Kenaf fibre was firstly treated with sodium hydroxide (NaOH) at 6% w/w followed by acidic treatment with different concentrations (0.5M, 1.0M and 1.5M). The PLA/kenaf nanofibre composites were referred as KC0.5, KC1.0 and KC1.5 according to acid concentration used. Differential scanning calorimetry (DSC) was done to investigate thermal properties of the composites. The glass transition, crystallization and melting temperature shows similar trend where 1.0M treated fibre composites gives better thermal properties than 0.5M and 1.5M treated fibre composites. Transmission electron microscopy (TEM) micrographs suggested the nanofibre dispersion in mixed-pattern; exfoliation and small agglomeration.

Abstract: In this paper, we have successfully synthesized TiO2 microsperes by solvothermal method using titanium (IV) isopropoxide as titanium source and ethanol as a solvent. The solution was thermally treated at relatively low temperature of 150 °C for 3 hours. The as-prepared and annealed of TiO2 microsphere were characterized using FESEM, XRD and Raman spectroscopy. The diameter of the microspheres was 1-6 µm. The X-ray diffraction and Raman spectroscopy studies show that the microspheres has anatase phase.

Abstract: Carbon nanotubes were synthesized from the aerosol-assisted catalytic CVD method using palm oil as the precursor and 0.05M zinc nitrate solution as the catalyst. The deposition temperature of the single furnace aerosol-assisted catalytic CVD ranged from 750 to 950 oC. The samples were then characterized using field emission scanning electron microscope (FESEM), Raman spectroscopy and thermogravimetric analysis (TGA). CNTs with different diameters and distribution were produced at certain deposition temperature and amorphous carbons were also present in the samples.

Abstract: ZnO hexagonal rod structure were prepared by immersion method deposited onto Si (Si/ZnO) and gold-seeded Si substrate (ZnO/Au/Si). The annealing temperatures were varied from 400, 500 and 600 °C. The effect of annealing temperature on the surface morphology and photoluminescence characteristics was investigated. The samples were characterized by Field Emission Scanning Electron Microscope (FESEM) to study their morphology and structural properties while the optical properties were characterized at room temperature using Photoluminescence Spectroscopy. The shape of ZnO showed growth of rods with hexagonal shape. As the annealing temperature increased, the morphology study indicates that diameter size of ZnO decreased while the crystallinity increases. The structures has high surface area, is a potential metal oxide nanostructures to be develop for optoelectronic devices and chemical sensors.

Abstract: A technique to monitor transesterification of waste cooking oil (WCO) is presented. The technique was developed based on analogue signal from WCO, fatty acid methyl ester (FAME) and commercial palm oil (CPO). A low-pass filter design for the photodiode was used to obtain the characteristic analog signal generated by these oil samples and the signal was correlated to absorbance spectra of the oils using data from Fourier transform infrared (FTIR) equipment. A match was made between the analogue signals of the oil samples and calibrated against the FTIR spectra at 95% confidence level. Depletion of WCO during transesterification in a batch reactor correlated with the time observed for peak yield during biodiesel production. The results of the technique are discussed as a possible way to monitor transesterification process in a batch reactor.

Abstract: In the current study, high density polyethylene (HDPE)/ ethylene propylene diene monomer (EPDM) blend and organophilic montmorillonite (OMMT) filled HDPE/EPDM was develop aiming at enhancing the thermal properties. Maleic anhydride polyethylene (MAPE) agent and electron beam (EB) irradiation technique were applied as HDPE/EPDM blend and OMMT filled HDPE/EPDM treatments. HDPE/EPDM blend and OMMT filled HDPE/EPDM were first prepared via melt intercalation technique at 4 vol% OMMT loading. For EB irradiation technique, the absorbed dose was set at 100 kGy. The effectiveness of these surface modification treatments were compared with control one (no surface modification) and analyzed based on the thermal test as well as transmission electron microscope (TEM). It was found that the thermal properties of both HDPE/EPDM blend and OMMT filled HDPE/EPDM were significantly enhanced by EB irradiation technique as compared to the control and MAPE systems. Transmission electron microscope (TEM) illustrated the mixed intercalated and partial exfoliated structures of OMMT filled HDPE/EPDM with EB irradiation technique.

Abstract: The studies emphasis on the development of niobium alloyed ductile iron with higher strength comparing to unalloyed ductile iron. 0.5wt% to 2wt% niobium were added into mixture of ductile iron casting containing pig iron, carburizer and steel scrap, and nodulized through 1.6wt% Fe-Si-Mg addition in CO2 sand casting process. Samples were then machined according to TS EN 10001 standards for tensile test and ASTM E23 for Charpy impact test. In addition, Rockwell hardness test was also performed. Microstructure observations were made after 2% Nital chemical etched and the phase structures were validated through XRD analysis. It was found that addition of niobium in ductile iron provide significant enhancement in mechanical properties when compared to unalloyed ductile iron. Addition of higher amount of niobium had further increased the strength and impact toughness properties. The enhancement of the mechanical properties is expected to further expand the applications of ductile iron.

Abstract: Stir casting method is used in the production of SiC reinforced-aluminium metal matrix composite (AMMC) to enhance the properties of base metal. Different weight fraction of Silicon carbide, SiC (5 wt%, 10 wt% and 15 wt %) particulate-reinforced AMMCs are fabricated and characterizations of physical and mechanical properties of the materials are performed based on the experimental. The microstructure of the fabricated composite material are studied and analyzed. The results indicate that the mechanical properties of the composite, including yield strength, tensile strength and hardness are enhanced by the increment of the weight fraction of reinforcing phase. Nevertheless, the elongation and fracture toughness of the composite decreased as the reinforcing phase increased. This is mainly due to the brittleness of the SiC particles which act as micro void initiator.

Abstract: The present work reports the performance characteristics of Zn/MnO2 Leclanché cell employing an inorganic MCM-41 membrane separator. MCM-41 material comprises of one-dimensional, hexagonally ordered silicates mesostructure. The main advantage of MCM-41 membrane is its 3-in-1 functional features, viz. as ionic exchange channels, insulating layer between electrodes and electrolyte reservoir. Zn/MnO2 cell is constructed approximately to the size of R2025 coin cell. As the fabrication technique of MCM-41 membrane is merely by dip-coating process, it offers two advantages. First, the membrane could be prepared sufficiently thin and thus minimizing the internal losses of the cell. Second, it enables the construction of bipolar cell configuration with ease. Consequently, the results obtained demonstrate the volumetric energy density of Zn/MCM-41/MnO2 R2025 button cell has been extended by almost fivefold from 5.6 Wh/l to 26 Wh/l as bipolar cell configuration is utilized.

Abstract: Zinc-based alloy is developed as an alternative alloy for giftware material. However, zinc alloy has limitation such as its mechanical properties. Therefore, modifying the properties of zinc based alloy is needed to use it for giftware material. The effect of adding Sn on the mechanical properties and fractography of Zn alloys are investigated. The results indicate that adding 15 wt. % of Sn has significant effect on the improving of tensile strength and elongation of the zinc based alloy due to the formation of AgSn phase. The fracture surface of the tensile test specimen showed a mixed mode of fracture exhibiting ductile failure and brittle failure. Alloy with Sn content up to 15 % tends to have more ductile failure then the brittle one. The alloys of Zn-0.50Ag-15Sn have very good tensile strength and elongation, which are better than Zn-0.50Ag-1Sn and Zn-0.50Ag-7Sn alloys.