Azlan Ariffin

A Comparative Study on Curing Characteristics, Mechanical Properties, Swelling Behavior, Thermal Stability, and Morphology of Feldspar and Silica in SMR L Vulcanizates

Abstract Comparison studies on effects of feldspar and silica (Vulcasil C) as a filler in (SMR L grade natural rubber) vulcanizates on curing characteristics, mechanical properties, swelling behavior, thermal analysis, and morphology were examined. The incorporation of both fillers increases the scorch time, t 2, and cure time, t 90, of SMR L vulcanizates. At a similar filler loading, feldspar exhibited longer t 2 and t 90 but lower values of maximum torque, MHR, and torque difference, MHR–ML than did silica-filled SMR L vulcanizates. For mechanical properties, both fillers were found to be effective in enhancing the tensile strength (up to 10 phr), tensile modulus, and hardness of the vulcanizates. However, feldspar-filled SMR L vulcanizates showed lower values of mechanical properties than did silica-filled SMR L vulcanizates. Swelling measurement indicates that swelling percentages of both fillers-filled SMR L vulcanizates decrease with increasing filler loading whereas silica shows a lower swelling percentage than feldspar-filled SMR L vulcanizates. Scanning electron microscopy (SEM) on fracture surface of tensile samples showed poor filler–matrix adhesion for both fillers with increasing filler loading in the vulcanizates. However, feldspar-filled SMR L vulcanizates showed poorer filler–matrix adhesion than did silica-filled SMR L vulcanizates. Thermogravimetric analysis (TGA) results indicate that the feldspar-filled SMR L vulcanizates have higher thermal stability than do silica-filled SMR L vulcanizates.

Tensile, Swelling, and Oxidative Degradation Properties of Crosslinked Polyvinyl Alcohol/Chitosan/Halloysite Nanotube Composites

Glutaraldehyde (GA) crosslinked polyvinyl alcohol (PVA)/chitosan (CS)/halloysite nanotube (HNT) composite films were prepared using a wet casting method. The tensile, morphology, thermal degradation, swelling, moisture, and oxidative degradation properties of crosslinked composite films were carried out. The presences of crosslinking in the composite films were confirmed by FTIR result. The tensile strength of the crosslinked composite films increased up to 0.5 wt% of HNTs loading. Increasing HNTs reduced the thermal degradation, swelling, and moisture properties of crosslinked composite films reduced with the increase of HNTs content. Results also indicated that the crosslinked composite films were degraded using Fenton reagent.

Curing Characteristics, Fatigue and Hysteresis Behaviour of Feldspar Filled Natural Rubber Vulcanizates

Curing characteristics, fatigue, and hysteresis behaviour of feldspar filled SMR L vulcanizates and feldspar filled ENR 50 vulcanizates were studied. Two different types of natural rubber, SMR L and ENR 50 having 0 and 50 mol% of epoxide groups were used. The feldspar filled natural rubber vulcanizates were compared at similar filler loading which were used at 0, 10, 20, and 30 phr of filler loading. The curing characteristics such as scorch time (t 2) and cure time (t 90) slightly increased with increasing feldspar loading for both rubber vulcanizates. Besides t 2 and t 90, maximum torque (M HR) significantly increased for both rubbers with increasing feldspar loading. The fatigue test showed that fatigue life decreased with increasing extension ratio, strain energy and filler loading. As the filler loading increased, the poor wetting of the feldspar by the rubber matrix gave rise to poor interfacial adhesion between filler and rubber matrix. Results also indicate that the vulcanizates with the highest feldspar loading exhibited the highest hysteresis. The feldspar filled SMR L vulcanizates showed higher fatigue life and lower hysteresis compare to feldspar filled ENR 50 vulcanizates.

The Effect of Feldspar Loading on Curing Characteristics, Mechanical Properties, Swelling Behavior and Morphology of Natural Rubber Vulcanizates

ABSTRACT Feldspar is being used herein as a filler in natural rubber vulcanizates. Two different types of natural rubber, SMR L and ENR 50 having 0 and 50 mol% of epoxide groups and semi-efficient vulcanization were used. The scorch time, (t2) and cure time, (t90) of both rubber vulcanizates slightly increased with increasing feldspar loading. At a similar feldspar loading, the ENR 50 vulcanizates showed shorter t2 and t90 than SMR L vulcanizates. Besides t2 and t90, maximum torque, (MHR) and torque difference (MHR−ML) were also investigated. Results indicate that MHR and MHR−ML increase for both rubbers with increasing feldspar loading. Swelling test results showed a reduction in the swelling percentage for both rubbers with increasing feldspar loading. At a similar filler loading, SMR L vulcanizates showed lower swelling percentage than ENR 50 vulcanizates. The mechanical properties such as tensile strength (up to certain filler loading), tensile modulus and hardness increased with increasing feldspar loading for both rubbers. However, at a similar feldspar loading, the mechanical properties of SMR L vulcanizates are higher than ENR 50 vulcanizates.

Review: Single Screw Extruder in Particulate Filler Composite

This review is designed to be a comprehensive source for single screw extruder research in the scope of particulate filled composite. This review includes factors effecting processing of particulate filled composite using a single screw extruder. The mixing requirements for a particulate filled composite analyzed and discussed in terms of single screw extrusion. The factors for achieving effective mixing of this type of composite are also discussed.

Electrophoretic Deposition of Biphasic Calcium Phosphate (BCP) Coatings on 316L Stainless Steel at Room Temperature

Electrophoretically deposition of Biphasic calcium phosphate on 25 × 10 × 1.2 mm (length, width, and thickness) 316L stainless steel plates using ethanol as dispersing medium; It was achieved on the cathode with constant voltages 20, 30, 50, and 100 V during 20, 30, 60, 90 and 120 seconds, respectively. After deposition, the samples were dried at room temperature for 24 hours and deposition weight and thickness of the coatings were measured. The coated samples were sintered in a tube furnace at 800 °C for 1 h in an argon atmosphere. After the sintering, the surface morphology and structure and phase composition of the samples were studied by a scanning electron microscope (SEM), energy dispersive spectrometry (EDX) and phase purity of the coating material by X-ray diffraction.

Effect of Temperature on BCP Ceramics Coating on 316L Stainless Steel Using Electrophoretic Technique

Biphasic calcium phosphate (BCP) coatings on a medical grade 316L stainless steel substrate were prepared by electrophoretic deposition (EPD) using ethanol as a dispersive medium. The deposition voltage of 30V was applied for 1 min at 25, 40 and 60 °C, respectively. The coated substrates were sintered in a vacuum furnace at 800 °C for 1 h. The surface morphology, structure and phase composition of the coatings was investigated by scanning electron microscopy (SEM) and X-ray diffraction (XRD). The results showed that by increasing deposition conditions of voltage and temperature, crack occurrence and morphological changes increased in the produced coatings. The optimum condition for crack-free surface was at 30 V at 25 °C.

Preparation and Characterization of Biphasic Calcium Phosphate Coatings on 316L Stainless Steel Fabricated by Electrophoretic Deposition

Biphasic calcium phosphate (BCP) ceramic is a synthetic biomaterial exhibiting a chemical composition similar to that of tooth mineral. Therefore, it is viably used in coating metallic implants manufactured from metals and alloys, such as titanium and stainless steel. In the present study, electrophoretic deposition (EPD) has been attempted for depositing BCP coatings on 316L Stainless Steel substrate followed by vacuum sintering at 800 °C for 1 h. The surface morphology, thickness, compositions and microstructure of the BCP coated 316L SS was investigated by scanning electron microscope (SEM), energy dispersive spectrometer (EDS), X-ray diffraction (XRD) and the bond strength of the coating was measured.

Application of a pre-hydrolyzed iron coagulant on partially stabilized leachate

AbstractLeachate is a liquid produced from the biodegradation of solid waste in landfill and is normally referred as highly polluted wastewater. Various treatment methods are available and it is highly depended on the characteristics of the leachate. One of the common and simplest methods is using coagulation process. The application of pre-hydrolyzed coagulants in coagulation process is well known for water and wastewater treatment. However, information on the application of pre-hydrolyzed coagulants, especially pre-hydrolyzed iron (PHI), in partially stabilized leachate treatments is not well documented. This study examined the application of PHI on the partially stabilized leachate by determining the optimum basicity ratio, pH, and dose through the removals percentage of suspended solid (SS), color, and chemical oxygen demand (COD). Laboratory jar tests revealed that the optimum PHI basicity ratio, pH, and dosage were 0.1, 5, and 0.2 g/L Fe, respectively. The optimum removals of SS, color, and COD were...

A Comparative Study of Matang and Kuala Sembeling Landfills Leachate Characteristics

Understanding the characteristic of leachate is important since it has complexity properties because of the variation in its composition. This study, analyzed and compared two leachate from two landfill sites, namely, Matang and Kuala Sembeling landfill. Leachate raw samples were collected by grab sampling and were analyzed for 11 parameters. The average concentrations of MLS and KSLS leachate such as BOD5 (146 and 61 mg/L), COD (828 and 363 mg/L), pH (7.6 and 8), SS (407 and 220 mg/L), ammonia (868 and 367 mg/L) , BOD/COD (0.18 and 0.14), cadmium (0.19 and 0.1 mg/L), cuprum (0.09 and 0.1 mg/L), nickel (0.17 and 0.1 mg/L), manganese (0.09 and 0.22 mg/L), and ferum (2.3 and 8.3 mg/L) were recorded, respectively. The results revealed that the both landfills are categorized as partially stabilized leachate. The strength of leachate pollutants from MLS are higher than KSLS because of the higher fraction of organics concentration. There are 5 parameters (BOD5, COD, ammonia, SS and cadmium) in MLS and 7 parameters (BOD5, COD, ammonia, SS, cadmium, manganese and ferum) in KSLS exceeded the permissible limit stated by MEQA (1974), and so leachates from both landfill sites need a suitable treatment to reduce the concentration of the leachate pollutants before discharge into environment.