Papers by Keyword: Palm Stearin

Abstract: Addition of high percentage of palm stearin (PS) into a blend with high density polyethylene (HDPE) may result in the blend instability and poor flowability of the composite during injection moulding process. The undesirable effect of the PS addition arises from lack of interaction between the PS and HDPE matrix. To improve the interaction between the two components, a compatibilizer was added to the blend. The objective of this work is to study the effect of glycerol monostearate (GMS) compatibilizer concentration (1-5 wt%) on the HDPE-PS composite with PS content of 40 wt.%. The thermal properties of the HDPE-PS composite were characterized using torque analysis, differential scanning calorimetry (DSC) analysis and rheology analysis. It was found that melting temperature of the HDPE-PS composite decreases with GMS concentration. The presence of GMS in the HDPE-PS composite had improved composite flowability indicate suitability of the GMS as compatibilizer for the HDPE-PS composite.

Abstract: Calcium methoxide obtained from quick lime is used as a solid catalyst in the transesterification reaction between palm stearin with methanol using tetrahydrofuran (THF) as co-solvent for biodiesel production. In this work, quick lime was used to prepare calcium oxide by heat treatment at the different temperatures, after that calcium oxide was further reacted with methanol to produce calcium methoxide catalyst. The properties of Calcium methoxide (Ca(OCH₃)₂) was characterized by XRD, SEM, BET, TGA, EDX and FTIR. The optimum conditions of biodiesel production were studied through response surface methodology and central composite design. The conversion of fatty acid methyl ester (FAME) was determined by proton nuclear magnetic resonance spectroscopy (¹H-NMR). The results depicted that calcined quick lime at 800 °C for 3 h contained high calcium oxide content. The Ca(OCH₃)₂ catalyst prepared at 65 °C for 3 h gave high surface area and catalytic activity. The optimum conditions for biodiesel production were 2.33% w/w of catalyst, 1 : 9.39 of palm stearin to methanol molar ratio, 102 min of reaction time and 9.07% v/v based on methanol of THF co-solvent, the same condition gave 98.23% of FAME conversion.

Abstract: The dental restorations by the usage of implants have been one of the most favourable treatment. However, the existing dense dental implant causes overloading towards the human bone that triggers ‘stress shielding effect’ and also implant loosening. This paper focused on the development of highly porous Ti-6Al-4V dental implant by metal injection molding with palm stearin binder system with an addition of sodium chloride as space holder which has been established in the fabrication of porous Ti-6Al-4V. The evaluated compositions consist of the powder volume fraction of 63vol% and 65vol%. SEM analysis shows that highly porous Ti-6Al-4V dental implant were obtained. The average density is 3.325g/cm³ for 63vol% sample and 3.915g/cm³ for 65vol% sample. While for the Vickers hardness are 113.68HV and 162.8HV for 63vol% and 65vol% respectively.

Abstract: Development of binder system based on natural resources is one the main interest among researchers in ceramic injection moulding (CIM) with the main aim of processibility of complex biomedical implant. In this paper, the influence of single binder comprised of palm stearin mixed with HAP powder was investigated. The powder and binder mixture, generally known as feedstock was analyzed for its flowability in order to get some insight for injection moulding purposes. Two different mixing temperatures were investigated for preparing the feedstock; 160°C and 70°C. The feedstocks viscosity was then evaluated using a capillary rheometer at temperature range from 70°C to 90°C. The results clearly showed that the use of 100% palm stearin was promising in providing required pseudoplastic flow for injection molding. The injection molding process can be carried out at relatively low temperature in comparison with the conventional binder systems used.

Abstract: This paper reports on the compatibility of hydroxyapatite (HAP) combined with single based binder, palm stearin for ceramic injection molding in order to obtain the best properties. The feedstock was prepared at a powder loading of 62 Vol % using 5μm fine ceramic powder of hydroxyapatite and the binders consisting of 100% of palm stearin. The specimens underwent thermal de-binding and then sintered in an electrical furnace within a temperature range from 500°C to 1000°C. The resulting exhibit promising properties which the final product produced after the sintering process was successfully tested by mechanical testing. It is proven that even the specimen only consists of single based binder can form a complex shape without collapse just like the specimen obtained by the conventional binder system. Therefore, the fabrication also is more towards green processing technology and energy conservation due to the binder used was from natural local resources and used lower processing temperature at 50°C to 70°C for mixing and injection molding.

Abstract: Debinding process of injection moulded Ti-6Al-4V feedstock was divided into two parts: solvent debinding process to eliminate palm stearin (PS) and thermal pyrolysis to eliminate polyethylene (PE). Solvent debinding process used heptane at optimum temperature, 60°C to remove PS binder completely as temperature is the only parameter that can be optimized. Thermal pyrolysis parameters for removal of PE binder from the injected 65vol% Ti-6Al-4V feedstock have been optimized by using Taguchi method. Heating rate, temperature and time were the selected factors during experiment to be applied in the L₉(3⁴) Taguchi orthogonal array (OA) to find the best set of parameters to produce highest density of brown part. Thermal pyrolysis process was done at optimum parameters: heating rate: 5°C/min; temperature: 510°C; and time: 90 minutes. Analysis of Variance (ANOVA) was employed to find the best signal to noise ratio (S/N) to express the contribution of the factors towards quality characteristic. Based on the results, heating rate has the greatest contribution (54.63%), followed by duration time of thermal pyrolysis (24.40%) and temperature (19.25%).

Abstract: This paper reports on the compatibility of waste rubber binder combined with conventional binder, paraffin wax and local binder, palm stearin for M2 High Speed Steel injection molding in order to obtain the better properties. The feedstock was prepared at a powder loading of 65 vol.% using 22um M2 High Speed Steel powder and the binders consisting of 55wt.% paraffin wax/palm stearin, 21wt.% polyethylene, 14wt.% waste rubber and 10wt.% stearic acid. The specimens were then sintered in vacuum atmosphere within a temperature range from 1200°C to 1260°C. The results shown even the best properties is obtain from the conventional binders, paraffin wax, thus the properties of local binders palm stearin is still comparable and good. The maximum density of paraffin wax binder was 8.095g/cm³ achieved at temperature 1250°C and palm stearin binder was 8.111g/cm³ achieved at temperature 1240°C. Therefore, in term the best strength of paraffin wax was 2351Mpa whilst palm stearin was 2210MPa, both recorded at temperature 1230°C.

Abstract: Metal Injection Molding (MIM) is widely known as net shape process to mass production for complex shape. In this study polyethylene and palm stearin was used as binder system for composite HA and Ti6Al4V. Ti6Al4V has spherical shape with particle size 25 μm and Hydroxyapatite has particle size 5 μm. Brabender^® was used to mix HA and Ti6Al4V powder and binder for making feedstock, rheological properties of feedstock was examined by capillary rheometer. Effects of temperature, viscosity, shear rate and activation energy were discussed in this paper. Binder was removed by thermal debinding. Rheological test showed feedstock of composite HA and Ti6Al4V shows pseudoplastic behavior. Sintering was conducted on 1200°C by argon with holding time 2 hour.

Abstract: This study investigated the flow behavior of feedstock containing hydroxyapatite (HAp) powder with palm stearin (PS) based binder system. The HAp was synthesized via chemical precipitation method with the use of waste of clamshells. The result showed that single phase synthesized HAp was successfully formed at annealing temperature and pH solution of 850°C and 6.5, respectively. The synthesized HAp with a volume fraction of 65% was then mixed with PS and and Polyethylene binder at 160°C to prepare a feedstock. From the rheological test result, it was found that the feedstock exhibited a pseudoplastic behavior with low values of shear sensitivity in comparison with commercial HAp.

Abstract: The most demanding high temperature application requires nickel-based super alloys, named Inconel 718 (IN718) is a precipitation hardenable nickel chromium alloy containing significant amount of iron, niobium and molybdenum along with lesser amounts of aluminium and titanium. The development of IN718 for metal injection molding was already proposed to provide increased resistance to distortion during and prior to debinding. This paper reports on the effects of sintering temperature on physical and mechanical properties of IN718 alloy. IN718 powder (60 vol%) with binder formulation (40 vol%) consists of polyethylene (PE) and palm stearin (PS) were mixed homogeneously and injected to produce green compacts. The binders then was removed and sintered at 1100 °C and 1200 °C for 8 h respectively. During sintering, the debound part is heated, which is allowing densification of the powder into a dense solid followed by elimination of pores. The sample sintered in vacuum condition at atmosphere 10^-5 mbar whereby samples sintered at 1100 °C, show the density of 6.806 g/cm³ compared to samples sintered at 1200 °C is 8.186 g/cm³. Super alloy sintered at 1200 °C exhibited better densification rate with lower porosity. The preliminary results indicate that super alloy can be used in the MIM fabrication of nickel based super alloys to produce high-density sintered parts.