Abstract: Micro-perforated panel (MPP) has been widely considered as a very promising alternative in absorbing sound by utilizing the concept and mechanism of Helmholtz resonator. Most of the existing MPP are made of metallic material such as aluminium or stainless steel. In this study, biodegradable composite micro-perforated panel (BC-MPP) made from kenaf fibre and polylactic acid (PLA) will be implemented. Impedance tube test shows that BC-MPP possessed excellent sound absorption properties and could rival with conventional MPP. The peak absorption of BC-MPP is also more significant compare to conventional MPP as the peak absorption almost reaches unity.
Abstract: The project explained about what happened to fiber matrix interfacial shear strength, fiber tensile strength and fiber Young modulus when different alkali treatment settings were applied. Kenaf fiber were exposed to different alkali concentration, immersion duration and immersion temperature. To determine the interfacial shear strength (IFSS), unsaturated polyester matrix was utilised to expose the properties. The effects of alkali treatment on sample mechanical properties were successfully evaluated, whereby the treated sample's IFSS showed slightly higher value compared to untreated kenaf fiber at all settings. Meanwhile, the IFSS value was increased at low alkali concentration and decreased with the increment of alkali concentration percentage. On the other hand, untreated kenaf fiber tensile strength and Young modulus average value was 632MPa and 40.65GPa respectively. It was also established that the sample's tensile strength was keep reducing after treatment at all settings. At 30 minutes constant immersion duration, the percentage of kenaf fiber tensile strength decrement was 42.57% when other treatment settings increased. Furthermore, a decline pattern was obtained in term of sample tensile strength and Young modulus when the alkali treatment increased at all settings.
Abstract: Polyurethane (PU) materials are extensively used in the construction industry as core material insulation for sandwich panel application, such as wall cladding, structure insulation and roof panel. Demands on PU application have escalated given its significant advantages to reduce energy consumption. Meanwhile, rigid PU (RPU) foams are combustible materials characterized by rapid flame spread, high heat-release rates, and ability to produce large quantities of toxic gases in original form. Thus, flame-retardant (FR) additives are used to improve the thermal properties of PU. However, some commercial additives used today have are hazardous to humans and the environment, and their extensive application is limited by their negative effects on polymer mechanical properties. Accordingly, identifying materials that are environmentally friendly and harmless to humans has become urgent. Some alternative additives that are gaining research interest are clay and fly ash, which are natural and recyclable resources that can enhance the FR properties of other polymers. However, room for improvement is always present as the related technology is continually being developed. This review focuses on studies aiming to enhance the flame retardancy of RPU foam using fly ash and local clay as additives.
Abstract: This Extrusion permit in controlling electrical conductivity before composite materials undergo the manufacturing process. However, studies on electrical conductivity in high conductive polymer composite materials are still in preliminary stage. Thus, the studies on electrical conductivity model are crucial as it able in predicting the electrical conductivity hence minimizing the experimental conducted. In this study, conductivity model was conducted to validate the series of experiment. The electrical conductivity increases as shear rate decrease and the highest electrical conductivity of 3 S/cm is obtained which indicated that the shear rate is crucial in increasing the electrical conductivity of the composites compared to extrusion temperature hence it is consider in the modelling.
Abstract: Porous ceramic is a type of material that has highly open and partially interconnected pores. It has a wide range of applications which include catalyst support, electrical conductivity, refractory insulation of furnaces, filtration, adsorption, and separation. There are many conventional methods for producing silica foam including direct forming, steam heating, freeze casting and the polymeric sponge method which is also known as the replication method. In this study, SiO2-NiO foam was fabricated using 25wt. %, 30wt % and 35wt.% of SiO2 and 5wt.% of NiO under different sintering temperatures (850 °C and 1050 °C) via replication method. The morphologies of SiO2-NiO foams were observed using Scanning Electron Microscopy (SEM) while the identification of the different phases of foam was analysed using X-Ray Diffraction (XRD). The XRD analysis indicated that there were only SiO2 and NiO present and no additional phases were detected after sintering. The effects of sintering temperature (850 °C, 1050 °C) and SiO2 solid loading on properties such as apparent porosity, bulk density and shrinkage were investigated. It was found that when the solid loading of SiO2 and sintering temperature increased, the density of SiO2-NiO foams increased in the range of 0.6373 g/cm3 to 0.8165 g/cm3. On the other hand, the porosity percentage obtained increased from 78.51 % to 81.63 %. The density and porosity analyses showed that the density of foam increases when the porosity of SiO2-NiO foam decreases. However, the shrinkage after sintering ranged between 3.5081cm to 6.9975 cm at 850C ̊ and 7.3618 cm to 8.3704 cm at 1050 °C respectively. Thus, this proves that SiO2-NiO foam can be successfully fabricated through the replication method.
Abstract: Composites material were developed to acquire the desired material properties for biomedical applications in the recovery of defect bone by using Mg-doped HA/SA. Hydroxyapatite (HA) is the major constituent and essential component in bone and teeth. The stability of Mg doped HA/SA is influenced by starting precursor powders, preparation condition and method of preparing the samples for implant materials. The precipitation method was employed to prepare Mg-doped HA/SA powders by varying the composition of Mg at temperature 1300 C. The influence of Mg-doped HA/SA on phase composition, chemical structure and a functional group at various weight percentages (0.5wt%-1.5wt %) were accomplished through X-ray diffraction (XRD) and Fourier Transform Infrared Spectroscopy (FTIR) analyses. Based on the XRD and FTIR analyses, there is the presence of different peaks intensity and adsorption bands which indicates the shifted of peaks due to the doping process and a chemical interaction were observed between the inorganic and organic phase. Furthermore, the transformation of β-TCP due to increase in sintering temperatures are caused by the presence of magnesium ions. The OH stretching bands of HA/SA are trace by FTIR that identified the decomposition of Mg-doped HA/SA.
Abstract: Porous ceramic body is broadly utilized in the engineering discipline in this globalization era especially in the industrial applications. This is due to the advantages of one of the ceramic foams characteristics that can exhibit highly open pore and have a good interconnectivity. At the present study, the formation of Silica-Nickel oxide (SiO2-NiO) foams was developed by using the replication method with various solid loadings of 20wt. %, 25wt. %, 30wt. %, 35wt. % by adding a fixed amount of 5wt. % composition of Nickel Oxide (NiO) and sintered at a temperature of 1250°C. The Polyethylene Glycol (PEG) and Carboxymethyl Cellulose (CMC) as the binders to bind the particles and as thickening agent for the slurries formation. The cylindrical shape polyurethane acts as a template of the SiO2-NiO foams. The properties of physical and mechanical of the SiO2-NiO foams are being characterized through the morphology analysis via the Scanning Electron Microscope (SEM). Bulk density and apparent porosity tests are determined by adapting the Archimedes Principles. The compressive test has been carried out to identify the compressive strength of SiO2-NiO foams. The results obtained during the morphology analysis show the size of the pores appeared differently between the ranges of 268.81µm to 516.17µm. The result of the density and porosity of the porous SiO2-NiO foams recorded results between the ranges of 0.452g/cm3 to 0.775g/cm3 and 68.5% to 81.2%. This indicates that the variable of solid loading reveals the effect on the properties of the SiO2-NiO foams. Thus, the increasing of the solid loading will decrease the average size of the pores. However, with the decreasing of the average size of the pores will increase the density and the compressive strength of SiO2-NiO foams.
Abstract: The correlation between calcination temperature with the morphological, porosity and density of Sm0.5Sr0.5CoO3−δ/ Sm0.2 Ce0.8O1.9 incorporation with binary carbonate prepared by high energy ball milling (HEBM) method has been investigated. The composite cathode, samarium strontium cobaltite-samarium doped ceria carbonate (SSC:SDCc), was developed and scrutinised as for potential cathode materials in solid oxide fuel cell (SOFC) applications. This research studied the influence of carbonate in composite electrolyte, SDCc towards the composite cathode properties. The composition of 50 wt.% of SSC was chosen to be added with 50 wt.% of SDCc powder. The prepared powders of composite cathode SSC5:SDCc5 were then undergone calcination process at different operating temperatures which has been varied from 600°C, 650°C, 700°C and 750°C and all prepared pellets were sintered at 600 °C. The morphological properties of the composite cathode powders were observed via FESEM micrograph, and the average particle sizes of the composite powders were measured via SmartTiff Software. The total porosity (%) of the SSC5:SDCc5 composite cathode pellets was determined using the Archimedes method. The FESEM micrograph revealed that the obtained composite cathode powder is homogeneous, fine with average of agglomerates sizes of 70–100 nm. By increased on calcination temperatures, the agglomerates size of the composite cathode and the density of the pellet increased. Meanwhile the results collected from porosity value are decreased. The porosity percentage lies in the range from 32.3% until 38.7%. Based on the overall results, lower calcination temperature, which is 600° lead to better morphological and physical results. In conclusion, the calcination temperature has a direct effect on the average size of SSC-SDCc composite cathode, porosity and density value but still in line within the acceptable range to serve as effective potential cathode materials for solid oxide fuel cells.
Abstract: This study presents the preparation of barium strontium cobalt ferrite (BSCF)–samarium doped ceria (SDC) added samarium doped ceria carbonate (SDCC) cathode for solid oxide fuel cell (SOFC). The aim of this study is to investigate the effect of heat treatment on compatibility and characterization of BSCF composite. Calcined BSCF was mixed with SDCC and SDC by ball milling at 150 and 200 rpm respectively. Subsequently, both were uniaxially pressed to form pellets and sintered at 600°C for 2 hours. The BSCF behavior of composite samples was characterized via X-ray diffraction to determine the crystalline phase of BSCF composite. Fourier transform infrared spectroscopy was used to determine the existence of carbonate bond. Field emission scanning electron microscopy was used to examine the grain morphology. The crystalline BSCF phase percentage increased and secondary phases reduced when the milling speed decreased. After milling, BSCF composites still displayed uniform elemental distribution. Heat treatment has an impaired crystalline phase of perovskite BSCF. Without heat treatment, the BSCF composites showed agglomerate and unmolded particles.