Mohd Al Amin Muhamad Nor

Properties of Mortar Containing Rice Husk Ash at Different Temperature and Exposed to Aggressive Environment

The properties of mortar containing rice husk ash at varying temperatures were studied. Three rice husk ash samples were prepared at different temperatures and with various colors, i.e., 600°C (pink), 800°C (grey), and 1000°C (white), all were used for this study. Ordinary Portland cement (OPC), a well known universal binder, was partially replaced with rice husk ash at 10, 15, 20, and 30% by weight of binder. The water to binder ratio (W/B) of the mortar was kept constant at 0.45. The mortars were subjected to seawater or saturated Ca (OH)2 solution. The controlled and exposed mortars were characterized using X-ray diffraction, FTIR spectroscopy and compressive strength test. The results show that the amount of silica present in RHA are varied with burning temperature and colors, approximately in the range of 95 to 97%. White RHA produced higher compressive strength both in seawater and Ca (OH)2 solution. Finally, white RHA with 15% replacement was most suitable to be used as additive in OPC, and showed good potential for use in seawater applications and alkaline environment.

The Effect of Flux to Physical and Chemical Properties of Ceramic Body Using Ball Clay from Kampung Dengir, Besut, Terengganu

The fluxing agent usually used to reduce the sintering temperature of ceramic production. In order to achieve this study, the potassium feldspar had used as a fluxing agent in range between 15.2 - 42.5 %. The mixture of slurry was formulated by using ball clay, silica, polyethylene glycol and potassium feldspar to produce the ceramic pieces. The sample was prepared by aging the mixed clay with additives and aging for 24 hours before casting on the flat mould to form rectangular ceramic pieces. The body pieces then undergo thermal treatment at temperature of 800C, 900°C, 1000°C, 1100°C and 1200°C for 2 hours with heating rate 5°C/min as to study the effect of flux towards sintering behavior of the samples. The characterization of the samples was conduct in order to study the chemical composition of sample. The effect of the fluxing agent towards sintering temperature was evaluated in order to investigate the firing shrinkage, density, porosity and water absorption. The result shows at temperature of 1100°C with increasing the amount of flux, the firing shrinkage decreasing from 18 to 13 %. Increasing the amount of flux had decrease the porosity and water absorption of ceramic pieces and the density of the ceramic pieces almost uniform. The optimum amount of flux was 42.5% and sintering temperature was 1100°C.

Effect of Na2O and K2O on the Solubility and Chemical Properties of P2O5-CaO-Na2O-K2O-Al2O3 Glass

The effect addition of Na2O on the solubility properties of phosphate glass of the composition, 45P2O5-18CaO-xNa2O-(34-x)K2O-6Al2O3, where x = 0,5,10,15 and 20 wt. %. has been studied. Glass transition temperature (Tg) of glass samples, weight loss and pH of the immersion solution were measured. The Tg value of the phosphate glass also decreased with the incorporation of Na2O up to 10 wt. % and increased with the incorporation of 15 and 20 wt. %. These results indicates that the solubility and Tg value of phosphate glass were highly influence by the glass composition. The substitution of Na2O to the phosphate glass system with the present of K2O has decrease the solubility of phosphate glass. The released of phosphate and calcium ion seem to decrease with the increasing of Na2O content in the glass composition.

Effect of Dispersant Addition on Properties of Ceramic Pieces from Kampung Dengir, Besut, Terengganu, Malaysia

The abundancy of ball clay can be transform into more useful form. This study was conducted to investigate the effect of different amount of dispersant on ceramic system. Ball clay from Kampung Dengir, Besut, Terengganu was used as starting powder while sodium silicate was used as dispersant to produce good flow ability, minimum viscosity and controllable ceramic slurry. Ceramic slurry was prepared by adding additives such as binder, flux, filler and dispersant, casted onto POP mould to obtain ceramic body. Ceramic then cut into test pieces (8cm x 2cm) and mixed for 2 h and aged for 2 days before dried at 70 °C overnight and sintered at temperature of 800-1200 °C in furnace for 2 h with heating rate 5 °C/min. Slurries also tested for rheological properties using rheometer (brand Thermo Haake). Viscosity and shear stress were measured to investigate the rhoelogical behaviour of slip with different amount of dispersant (0.03 mL to 0.06 mL/200 mL of sample). Characterization of raw samples has been done using X-ray diffractometer (XRD) showing the presence of kaolinite and quartz. Effect of dispersant on rheological behavior, rate of shrinkage, water absorption, porosity and density were investigated It was found that increase in amount of dispersant added exhibit the best rheological behavior, and 0.05 mL dispersant was the optimum amount in term of rate of shrinkage, water absorption, porosity and density. As a conclusion, 0.05 mL was the optimum dispersant which gives best rheological behavior and almost fault-free ceramic bodies

Influence of B2O3 on Phosphate Ion Released from SiO2-B2O3-P2O5-Na2CO3 Glass in Synthetic Seawater

Phosphates have been receiving important attention in various fields and one of the fundamental sources of nutrients required to be used as source of nutrients for plankton growth. The objective of this study is to determine the effect of boron oxide on phosphate ion released from the system SiO2-B2O3-P2O5-Na2CO3 glasses. The compositions of this glass system [wt%: (55-x)% SiO2- (15+x)% B2O3- 5% P2O5- 25% Na2CO3] where 15≤x≤40 % have been prepared with the different amount of B2O3 (30-55wt%) and P2O5 with Na2CO3 were fixed. The glass has been prepared by melting in the alumina crucible within 2 h of soaking time at 1300 °C in the furnace and cooled to room temperature. The obtained glass samples were crushed and sieved at mean size of 2 mm – 4 mm. The dissolution studies were determined through the immersion of the glass samples in 50 mL synthetic seawater for 30 days under static condition. The results were obtained and analyzed using Discrete Auto Analyzer. Fourier Transform Infrared (FTIR) with Attenuated Total Reflectance (ATR) method was used to determine the functional group sample of glasses and the glass phase was characterized by X-Ray diffraction (XRD) techniques. Dissolution studies showed that, the concentration of phosphate ion released decreased with increasing B2O3 content whilst, increased with immersion time. The obtained experimental data indicated that, the optimum concentration of phosphate ion (10.27 ppm) was achieved at 35 wt% of B2O3 at week three.

Palm kernel oil-based polyurethane film: Biocompatibility and antibacterial activity studies

In this study, polyurethane (PU) film was prepared from palm kernel oil-based polyester (PKO-p) via pre-polymerization with isocyanate/polyol group ([NCO/OH]). PU films were physically characterized to investigate the mechanical properties, thermal behavior, water uptake, water vapor transmission rates as well as biocompatibility and antibacterial activities against Gram-positive (Staphylococcus aureus) and Gram-negative bacteria (Escherichia coli). Results showed that PU 2 film exhibited optimum mechanical performance and thermal properties with the water vapor transmission rates at 267 ± 17 g m−2 d−1, comparable to commercial dressing. Biocompatibility studies revealed that PU films were non-cytotoxic to the human skin fibroblast cells (CRL2522) and exhibited bactericidal effect against both bacteria.

Development of hydroxyapatite from Setiu coral via hydrothermal method

Coral and converted coralline hydroxyapatites (CHAp) have been widely used in biomedical application as orbital implant and bone graft substitute. In this study, the effect of calcination temperature towards properties of hydroxyapatite were investigated. Three different species of corals which commonly found in Setiu, Terengganu was identified based on coral skeleton and its mean pore diameter was analysed using SEM image analyzer. Corals sample undergo hydrothermal process at calcination temperatures range from 200°C to 240°C with addition of di-ammonium hydrogen phosphate as mineralizer. Three species of corals was identified as Platygyra Lamellina sp., Leptoria Phrygia sp. and Pocillopora Damicornis sp. The mean pore diameter of Setiu corals are 0.751mm, 0.495mm and 0.313mm for Platygyra Lamellina sp., Leptoria Phrygia sp. and Pocillopora Damicornis sp., respectively. The XRD diffractograms showed that the raw corals was sucessfully converted to hydroxyapatite (HA) with presence of minor impurities for all type of corals. Calcination temperature of 240°C was found the best temperature to convert coral to coralline hydroxyapatite. Based on this finding, coral species found in Setiu, Terengganu has great potential to be used as bone graft substitutes.Coral and converted coralline hydroxyapatites (CHAp) have been widely used in biomedical application as orbital implant and bone graft substitute. In this study, the effect of calcination temperature towards properties of hydroxyapatite were investigated. Three different species of corals which commonly found in Setiu, Terengganu was identified based on coral skeleton and its mean pore diameter was analysed using SEM image analyzer. Corals sample undergo hydrothermal process at calcination temperatures range from 200°C to 240°C with addition of di-ammonium hydrogen phosphate as mineralizer. Three species of corals was identified as Platygyra Lamellina sp., Leptoria Phrygia sp. and Pocillopora Damicornis sp. The mean pore diameter of Setiu corals are 0.751mm, 0.495mm and 0.313mm for Platygyra Lamellina sp., Leptoria Phrygia sp. and Pocillopora Damicornis sp., respectively. The XRD diffractograms showed that the raw corals was sucessfully converted to hydroxyapatite (HA) with presence of minor impurities fo...

The Effect of Boron Oxide on Phosphate Ion Released from Borosilicate Glass in Seawater

Glasses in the system [wt%: (55-x)% SiO2-(15+x)% B2O3-15% P2O5-10% Na2CO3-5% Fe2O3] where 15 ≤ x ≤ 40 % have been prepared with the different amount (35-55 wt%) of boron oxide. The compositions were limited by fixing the P2O5 at 15 wt%, Na2CO3 at 10 wt% and fixing the Fe2O3 at 5 wt%. The objective of this study is to determine the effect of boron oxide on phosphate ion released from borosilicate glass in seawater. The glass has been prepared by melting in the alumina crucible within 2 hours of soaking time at 1300 °C in the furnace and cooled to room temperature. The obtained glass was crashed and sieved with yielding a mean size of 710 μm. The samples were immersed in seawater under dynamic condition by stirring at 310 rpm. The water sample was taken 6 times at every 15 minutes until 75 minutes and analyzed using Discrete Auto Analyzer. The functional group and morphological characterization on the glass surface have been investigated using Fourier Transform Infrared (FTIR) and Scanning Electron Microscopy (SEM). Analysis of the data indicates that the amount of 50 wt% boron was the best and optimum for the phosphate ion release which is 126.53 ppm.

Effect of Fe2O3 Contents on the Ions Release from Phosphate-Based Glass

Currently, phosphate-based glasses have been extensively studied for their special characteristic of being soluble in aqueous medium and capable of releasing ions. This paper presents the relationship between the solubility properties and ion released of phosphate glasses having a composition of 6Al2O3-15K2O-14Na2O-(20-x)CaO-xFe2O3-45P2O5, where x = 2, 4, 6 and 8 wt.%. Clear and free bubbles of dark green glasses were obtained from the used of conventional melting technique at 1300 oC. The ion released and weight loss studies were determined from the immersion of the glass samples in deionised water for about 16 weeks under static condition. IR spectra revealed the formation of phosphate units such as metaphosphate and orthophosphate unit around 1097 cm-1 and 1107 cm-1 with the presence of Fe2O3 in the glass system. SEM image of the phosphate glass structure before and after immersion seems to be associated with the solubility of these glasses. From the study, the concentration of Na+ and K+ release decreased when more Fe2O3 contents were added to the system. Fe2O3 stabilize the network structure via the formation of P-O-Fe bond which more hydration resistant towards water penetrating molecules.

Preparation and Characterization of Hydrophobic Ceramic Foam

Ceramic foam are a class of high porosity materials that are used for various applications. In this study, foam ceramic porcelain powder was produced by using polymeric sponge replication method at different solid content ranging from 30 to 50 wt. %. Properties of ceramic foam was characterized for porosity and density. Ceramic foam then grafted with methyltriethoxysilane (MTMS) at different concentration ranging from 0 to 9.0% v/v to determine hydrophobic effect and oil absorption capacity. From the results, it was found that the density of ceramic foam increased while porosity was decreased with increasing solid contents. It is clearly seen that, MTMS grafting contribute to hydrophobic effect of ceramic foam which enable repelling of water. The amount of oil absorbed by ceramic was found increased by increasing concentration of MTMS for all solid contents. As conclusion, MTMS give significant effects on hyrdophobic ceramic foam and produce good absorption capacity. The lower solid content produced better oil absorption compared to higher solid content due to presence of higher porosity.