Advanced Materials Research Vol. 858

Abstract: This study investigated the effect of severe plastic deformation (SPD) and artificial ageing treatment on mechanical properties of cast Al-Mg-Si alloy. 6061-T6 aluminum alloy was remelted and casted into a rod of 13mm in diameter and 60mm in length. The rod samples were then subjected to equal channel angular pressing (ECAP) for SPD process, up to 2 passes, through Bc route. Cast and ECAPed samples were solution heat treated at 530 °C, quenched in water and held at 180 °C at various ageing time to determine the effect of artificial ageing. Cast alloy consisted of α phase grains that were surrounded by Mg₂Si particles locating at the grain boundaries. The hardness increased with accumulative applied strain by 2-pass ECAP process with the value of 99.4 Hv. For heat treated samples, maximum hardness was achieved after 5-hour ageing.

Abstract: The aim of this research work was to investigate in vitro effect of the carbonate apatite/poly (ε-caprolactone) (CO₃Ap/PCL) on α-tricalcium phosphate (α-TCP) foam was produced by sintering CaCO₃ and CaHPO₄2H₂O at 1500°C for 5 h. It was then coated with carbonate apatite (CO₃Ap)/Poly-ε-caprolactone (PCL) (wt/wt=1/3) to improve both mechanical and biological properties. The initial cell attachment and proliferation of the bone marrow cells were carried out on the α-TCP and CO₃Ap/PCL-coated α-TCP foams. The cell proliferation was calculated by AlamarBlue assay. The cells were able to migrate and proliferate well on both α-TCP and CO₃Ap/PCL-coated α-TCP foams indicating an excellent biocompatibility. The incorporation of CO₃Ap on the coating layer improved cellular attachment and accelerated proliferation. Thus, CO₃Ap/PCL-coated α-TCP foam might be a promising candidate as implant material.

Abstract: The thermal behaviour of polymer layered silicate nanocomposite were characterised to compare the improvement of the nanocomposite with the pristine polymer. It is known that pristine polymers have some weakness in its thermal properties especially biodegradable polymers. The approach of making the nanocomposite out of modified layered silicate and biodegradable polymer is to enhance the thermal behaviour of the biodegradable polymer. The nanocomposites were produced by solution method technique using dichloromethane as a solvent and the two types of nanoclay were used. One was modified with transition metal ion and another type of nanoclay is pristine nanoclay. Wide angle X-ray diffraction (XRD) was used to characterise the structure of the nanoclay after the modification and the type of nanocomposite obtained. Melting temperature and degradation temperature of the nanocomposite were obtained by using differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA) respectively. Decrease in both thermal degradation temperature and melting temperature of the nanocomposites were observed.

Abstract: In this research, 6061-T6 aluminum alloys were welded using friction stir welding and tungsten inert as techniques in order to investigate the microstructure and mechanical properties. FSW of aluminium alloys has showed better mechanical properties compared to the conventional welding, tungsten inert gas (TIG). FSW weldment did not show any pores at the nugget zone compared to fusion zone in TIG weldment which produced a lot of pores.

Abstract: Nanosilica (NS) was recently used as a filler to improve mechanical properties, morphology behaviors of natural rubber (NR) composites and also for light colored product. NS is hard to disperse in NR composite compare to carbon black due to large number of Silanol (Si-OH) group leads to strong filler-filler interaction. Silane coupling agent was extensively used to improve reinforce efficiency of NS and also for good filler-matrix interaction by reducing Si-OH group. In this study, Bis[3-(triethoxysilyl)propyl] tetrasulfide (Si-69) and (3-aminopropy)triethoxysilane (APTES) were used as a coupling agents with various loading 1.5, 3, 4.5 phr in conventional sulphur vulcanization system. Both Si69 and APTES gave a significance of the NR compound processing. However, hardness was gradually decreased up to 4.5 phr due to plasticizing effect. Si-69 can increase crosslink density because of 4 molecular of sulphur (S) and its structure retarded the curing where APTES accelerated the cured because APTES has lower molecular weight and viscosity than Si-69.

Abstract: A hand lay-up and vacuum bagging method was used in this study to fabricate glass fiber/epoxy laminated composites and carbon fiber/epoxy composite laminates with multi-walled carbon nanotube (MWCNT). The density, flexural properties, and burning rate of the laminated composites incorporated with different concentration of MWCNT (0.5, 1.0, and 1.5 vol%) were investigated and analyzed. Trend in the density, flexural and burning rate of glass fiber composite laminates were compared to those of carbon fiber composite laminates. Effect of MWCNT concentration on glass fiber composites properties varies from carbon fiber composite laminates. Incorporation of 0.5vol% of MWCNT has increased flexural strength by 54.4% compared to 5-ply glass fiber composite laminates. Nonetheless addition of 1vol% of MWCNT has only increased flexural strength by 34% compared to 5-ply carbon fiber laminated composites. Incorporation of MWCNT has successfully reduced the burning rate of the glass fiber composites as well as the carbon fiber laminated composites.

Abstract: Reactive Blue (RB 19), also known as Remazol brilliant blue, is a widely-used colorant in various textile applications. RB 19 is very resistant to chemical oxidation due to its aromatic anthraquinone structure highly stabilized by resonance. Its relatively low fixation efficiency (75-80%) attributed to the competition between the formation of the reactive form (vinyl sulfone) and the hydrolysis reaction, results in its prevalence in textile wastewater discharges. In this study, electro-Fenton (EF) process, a popular advanced oxidation process (AOP) was used to treat RB 19 dye-containing simulated wastewater. The electrochemical reactor (0.5 L) used in all experiments had parallel plate/mesh electrodes coated with metal oxides. Synthetic textile wastewater was prepared by dissolving RB 19 dye (300 ppm) in distilled water. The effects of pH, initial [Fe²⁺], initial [H₂O₂] and current on RB 19 decolorization efficiency were investigated. Removal of 100 percent RB 19 was achieved at pH 2, 0.71 mM initial [Fe²⁺], 5 mM initial [H₂O₂] and 1.86 A in 20 minutes. High decolorization efficiencies and absence of sludge during the treatment process render the electro-Fenton process a viable treatment option for dye wastewaters.

Abstract: The effect of different types and loading of cleaning agent on the tensile properties and swelling properties of natural rubber latex film were investigated. The aim for this study is to find the cleaning agent which is compatible with natural rubber latex with optimum loading. In this study, there are two different amine based cleaning agent used which are Monoethanolamine (MEA) and Di-(3-aminopropyl) ether of diethylene glycol (DG). Swelling test was done to support the tensile results. It is found that tensile properties of the sample with MEA cleaning agent is higher than control sample (without cleaning agent) and sample with DG cleaning agent. For the best cleaning agent compound, the different loading has been tested and results showed that optimum loading of cleaning agent are achieved at 5 phr. The effects of both types of cleaning agents and different loading of cleaning agents on tensile properties and swelling properties for cleaning mold application are discuss.

Abstract: In this study, porous alumina was fabricated by using polymeric sponge method. The slurries were prepared by mixing alumina (Al₂O₃) and polyvinyl alcohol (PVA) powder in distilled water. Slurries with two different compositions (60 and 70 wt. %.) of solid concentration were prepared. Samples were dried in an oven at 80 °C for 24 hours and sintered at temperature of 1500 °C. The effect of solids concentration was studied. Characterizations such as density and porosity tests, compressive strength as well as microstructure morphology were then used to analyze the sintered porous alumina samples. Specimens with 60 wt. % of solid loadings showed the higher porosity (88.06%) and pores structure more clearly interconnected. However, specimens with higher strength, 0.55 MPa, were obtained by using slurry with solid loadings of 70 wt. %.