Advanced Materials Research Vol. 1087

Abstract: In this study, high-resolution X-ray photoelectron spectroscopy (XPS) has been used to study the chemical interaction between copper ion and chitosan thin film. The chitosan solution was synthesized by homogeneous reaction of medium molecular weight chitosan in aqueous acetic acid with glutaraldehyde as crosslinking agent. Then the solution was deposited on glass cover slip by spin coater to form a thin film. The functional group and chemical binding of crosslinked chitosan thin film has been confirmed by XPS. XPS revealed that copper ion adsorbed to the crosslinked chitosan thin film and the functional groups involved in the adsorption mechanisms of copper ion on the thin film were determined.

Abstract: NiO-based ceramic has shown high dielectric constant with 10³-10⁵, as well as high dielectric loss. Previous studies showed that doping with monovalent cations can cause a considerable decrease in dielectric loss. In this research, the effect of Lithium carbonate (Li₂CO₃) dopant on NiO was investigated. The electroceramic of Li_xNi_1-xO were prepared by using solid state reaction method. The mixture of Li⁺ and NiO were ball milled for 24 hours. The samples were calcined at 800oC for 6 hours, pressed into pellet shape at 750 MPa and sintered at 1200°C for 10 hours. The sintered pellets were subjected to XRD, SEM, density testing and Impedance analyzer. XRD result shows the single phase formation of Li_xNi_1-xO. The grain becomes larger with the increament of Li⁺ mole %. The dielectric constant of Li_xNi_1-xO decrease with the increasing frequency. The highest dielectric constant was observed in x= 0.03 with 5210 at frequency range of 1GHz to 1MHz.

Abstract: The effect of recovered carbon fiber (rCF) to the burning property of polyurethane composites was investigated. The carbon fiber reinforced polymer (CFRP) in mat form was first glycolysed at 190-200 oC and characterized by FTIR, TGA, DSC and SEM analyses. The rCF was added at 0, 0.5, 1.0 and 1.5% (w/w). The polyurethane filled with recovered carbon fiber composites (PU-rCF) have also undergone burning test. The TGA analysis of PU-rCF indicated the percentage of weight loss decreased from 95.6% to 91.4% as rCF content increased. The DSC showed the glass transition temperature, T_g of PU-rCF increased with increasing addition of rCF from 56.7 to 63.0oC. The burning rate of the PU-rCF decreased from 6.1 mm∙s^-1 to 2.8 mm∙s^-1 with increasing rCF. The FTIR analysis confirmed that there was no chemical interaction between the rCF and PU. The addition of rCF to PU has improved the burning property of the composite.

Abstract: This study presents the experiments on the in-situ powder XRD on pure hydrous ferrous sulfate (FeSO₄.nH₂O) mineral. The progress of this mineral was monitored at different relative humidities and temperatures. The phase transformation from melanterite (FeSO₄.7H₂O) to rozenite (FeSO₄.4H₂O) and the phase transformation of rozenite (FeSO₄.4H₂O) to szomolnokite (FeSO₄.H₂O) were obtained.

Abstract: The XRD and EDX analyses were used to identify the type of phosphate precipitate from anaerobically digested liquor of wastewater screenings. The measurements confirmed that the main phosphate compound produced from the experiments was CaCO₃ and HA when the Mg:P molar ratios were 1.56:1 and 2:1, respectively. The precipitation at 1.56:1 was the initial molar ratio without chemical amendment, whereas 2:1 was carried out by chemical amendment. The results indicate that the presence of foreign ions such as calcium ion in high concentration may affect the formation of phosphate precipitates. This study shows that precipitation at 2:1 is suitable to recover phosphorus from wastewater digested liquor in the form of HA, as proved by the XRD pattern and further supported by EDX analysis. According to previous studies, the phosphate precipitate has a potential as a fertiliser or soil conditioner that can be used for agricultural purpose.

Abstract: The aim of this study is to determine sensitivity of new recipes polymer gel HEMATEG with varied x-ray exposure by using UV-visible spectrophotometer as an evaluation technique. The gels were irradiated by x-ray radiation and the polymerization of HEMATEG were followed. Polymerization was read based on absorption spectra in the range wavelength UV 300 nm to 700 nm. The dependency of polymerization with increasing of exposure dose was determined by changes in the band gap energy (E_g) and Urbach energy (∆E). In the UV-visible region, E_g with indirect transition of HEMATEG were decreased with increasing radiation dose while, ∆E were increased with increasing radiation dose. This observation supported the increase of structured disorder of the polymer with increasing radiation dose. This study proved that HEMATEG had a high potential to be used as a 3-dimensional dosimeter in the diagnostic x-ray.

Abstract: The effects of surface oxidation of etched metallic Zn foils by hot water treatment for variable times and temperature investigated. ZnO nanostructures were obtained after undergoing hot water treatment at 50°C and 90°C for 2 to 24 hours. The SEM morphology showed ZnO nanostar-like and nanoneedle-like were observed with different hot water treatment temperature. XRD analysis confirmed the existing of ZnO nanostar-like and nanoneedle-like in a hexagonal wurzite structure. Growth of peak on (002) direction confirmed ZnO crystals are columnar in shape and anisotropic with wurzite structure oriented along c-axis. On the basis of the changes in morphology and microstructure induced by hot water treatment, it is concluded that the formation of ZnO are promising at low temperature.

Abstract: Corrosion is the reaction between the material and the environment that cause degradation of the material. Corrosion reduces the essential properties of materials such as strength, appearance, toughness and life expectancy. Carbon steels are composed of a mixture of metallic iron and carbon and being used extensively in every sector due to good mechanical properties and good cost. However, carbon steel are every susceptible to corrosion attack especially in corrosive environment. The use of inhibitors is one of the best options to protect against corrosion on metals and alloys especially in a closed system. Inhibitor is a chemical substance which can reduce corrosion attack when added into electrolyte. The organic inhibitor used in this study was from banana peel (scientific name Musa sapieutum) to extract tannin-a compound which can provide protective layer on metal [1-3]. The results elucidate that banana peel can be used as green inhibitor on canbon steel, however, the effect only can be seen when added with 10% and more. The immersion test was done to evaluate the effect of corrosion product to corrosion rate. The results explained that corrosion rate fluctuated during immersion period due to developed and dissolved of soluble product into electrolyte. The research provide a set of data elucidate that corrosion product developed on carbon steel cannot provide corrosion protection on carbon steel, however, using green inhibitor in high concentrations which is purely not harmful to environment could prevent corrosion attack on carbon steel.

Abstract: Corrosion is commonly known as rust, an undesirable phenomena which destroys the luster and beauty of objects and cause shorter of life span. The objective for this research is to study the effect of using green inhibitor with seawater (NaCl) to the corrosion resistance of stainless steel 304. The green inhibitor was extracted from banana peel added with seawater (3.5% NaCl). The concentration of green inhibitor added was 5%, 10%, 15%, 20% and 25%. The test was conducted using the 3-electrode potentiostat to understand the behaviour of corrosion attack on stainless steel 304 at room temperature under static conditions. The results elucidate that green inhibitor has significant effect to the breakdown of passive film of stainless steel 304 in seawater. The forms of corrosion attack were viewed by using optical microscope. In conclusion, banana peel can be use as green inhibitor to increase corrosion resistance of stainless steel 304 and at the same time the abundant waste from local small industries can be recycled.

Abstract: The aim of this study was to investigate the mechanical properties and fire resistivity of medium density fibreboards (MDF) made from renewable biomass namely empty fruit bunch fibre (EFB) and palm-based pre-PU as the binder. Aluminium hydroxide (ATH) was added in the mixture of EFB at size of 300 to 500 μm. The ratio of EFB to PU matrix was 35:65 with ATH at varying amount of 5, 10, and 15 wt% of the overall mass of the resin. The results showed that MDF-EFB has higher mechanical properties than MDF-EFB/ATH. However, the fire test indicated lower burning rate (from 0.15 mm/s to 0.27 mm/s) as the percentage loading of ATH increased.