Zaleha Mustafa

Development and characterization of charcoal filled glass-composite materials made from SLS waste glass

Glass-composite materials were prepared from the soda lime silicate (SLS) waste glass, ball clay and charcoal powder at various carbon content, of 1wt. % C, 5wt.% C and 10 wt.% C, fired to temperature of 850 °C as an alternative method for land site disposal method as well as effort for recycling waster glass. The effect of charcoal powder on the porosity, water absorption and hardness properties were studied. Phase analysis studies revealed the present of quartz (ICDD: 00001-0649, 2θ = 25.6° and 35.6°), cristobalite (ICDD 00004-0379, 2θ = 22.0° and 38.4°) and wollastonite (ICDD 00002-0689, 2θ = 30.1° and 26.9°). The results showed that the composite prepared from the mixture of 84 wt.% SLS, 1 wt.% of charcoal and 15 wt.% ball clay containing average pore size of 10 µm has projected optimized physical and mechanical properties. It is observed this batch has projected lowest water absorption percentage of 0.76 %, lowest porosity percentage of 1.76 %, highest 4.6 GPa for Vickers Microhardness.

Recent Advances in Polyethylene-Based Biocomposites

Abstract Polyethylene (PE), part of the polyolefins group, is one of the major sources of commodity plastics used as the matrix in the development of biocomposite materials. PE-based biocomposites have been extensively used in both for nonstructural and structural applications, due to the low cost, recyclability, and processing advantages as compared to synthetic based composites. In this chapter, the overview on the application of PE-based biocomposites is explained which includes its role to the biocomposite formulation, various processing methods involved, and the characterization techniques applied to determine the properties of the final composites. In addition, this chapter also describes examples on the application of PE-based biocomposites in several fields such as such as structural, packaging, coating, biomedical, and medical.

A review of the tensile and fatigue responses of cellulosic fibre-reinforced polymer composites

ABSTRACT The use of polymer-based composites has been gaining popularity in the industry over the last few decades. Their high strength to weight ratio and high fatigue resistance make these composites the preferred materials for a wide variety of applications. The current trend has inclined towards hybrid fibre reinforced composites owing to their outstanding characteristics compared to non-hybrid composites. Numerous research works have been conducted to study the fatigue life behaviour of such composite materials. This study addressed the monotonic and dynamic performance of non-hybrid and hybrid natural fibre based composite materials, and the factors that influence their fatigue performance, along with the stiffness decay of each composite material. Most studies have shown the superior potential of using natural fibres in place of synthetic fibres in those critical applications that involve tensile and cyclic loading.

Effect of Calcination Temperatures on Phase Transformation and Stability of β-Tricalcium Phosphate Powder Synthesized by a Wet Precipitation Method

Beta-tricalcium phosphate (β-TCP) was never synthesized directly using an aqueous method. As-precipitated powder from a wet chemical method needs to undergo a heat-treatment process (or calcination) to enable the intermediate phase (s) to be transformed into single-phase TCP. In this work, calcium hydroxide, (Ca (OH)2), and phosphoric acid, (H3PO4), were mixed as the precursor materials with a Ca/P ratio of 1.5,. The mixture was stirred at a fixed stirring speed of 200 rpm and a stirring duration of 2 hours. The precipitate thus obtained was filtered and dried overnight before being tested by differential scanning calorimetry and thermogravimetry (DSC/TG) up to 1300°C for thermal behaviour upon firing. The powders were then calcined at various temperatures (500°C, 700°C, 900°C 1000°C, 1100°C, 1200°C and 1300°C) for a duration of 2 hours. The calcined powders obtained were analysed by x-ray diffraction (XRD) to determine the transformation of phases. Monetite and hydroxyapatite were the phases detected after calcination at 500°C and 700°C, whilst at a temperature of 900°C up to 1300°C, only a single phase β-TCP was observed. Microstructural observation by scanning electron microscopy (SEM) was conducted on the β-TCP powders obtained at calcination temperatures of 900°C to 1300°C. The results showed a massive crystal growth of the aggregated particles, but even so, the phase remained stable as monolithic β-TCP.

Parameters affecting the synthesis of -tricalcium phosphate powder using a wet precipitation method

In this work, precursor materials that are normally used to directly synthesise hydroxyapatite (HA) were adopted to obtain tricalcium phosphate (TCP). Calcium hydroxide, (Ca(OH)2), and phosphoric acid, (H3PO4), with a Ca/P ratio of 1.5, were mixed as the precursor materials. The mixture was stirred at various stirring speeds ranging from 0 to 400 rpm, over a range of stirring durations of 1 to 4 hours. Upon completion of the reaction, the as-prepared powders were calcined at different temperatures ranging from 500C-1300C for a soaking duration that was varied between 1-4 hours. Differential scanning calorimetry (DSC) and thermogravimetry (TG) were used for thermal analyses to ascertain the calcination temperatures, whilst x-ray diffraction (XRD) was utilised to determine the phases formed before and after calcination. Field emission scanning electron microscopy (FESEM) was used to monitor the morphological changes at different calcination temperatures. Based on the XRD results, the phases formed were dependent on the processing parameters employed. This work has successfully ascertained that the most optimum parameters to synthesise singlephase β-TCP are a stirring speed of 200 rpm, a calcination temperature of 900C, a calcination soaking duration of 2 hours and a mixing duration of 1 hour. Microstructural observation conducted on the -TCP powders obtained at calcination temperatures of 900C to 1300C showed an aggregated structure of particles with massive grain growth as the temperature was raised up to 1300C.

Preliminary Study on the Mechanical Properties of Continuous Long Pineapple Leaf Fibre Reinforced PLA Biocomposites

This research work investigates the effect of using alkaline-treated continuous long pineapple leaf fibers (PALF) as reinforcement in bio-based poly lactic acid (PLA) polymer biocomposite. Alkaline treatment using NaOH solution was employed to improve the fiber-matrix adhesion, with the aim to enhance the mechanical properties of the biocomposites, in terms of its tensile and impact properties. In this study, both the plain PLA polymer and the PALF reinforced PLA biocomposites were prepared using compression moulding process. Thin films with nominal thickness of approximately 1 mm each were stacked in between continuous long PALF fibers prior to compression moulding via hot press machine to form biocomposites plate. Two types of mechanical testing were performed, i.e., tensile test (ASTM D3039) and impact test (ASTM D6110). Significant enhancements are observed when the plain PLA were reinforced with the PALF long fiber, with the biocomposites showing two times better the tensile strength and modulus, with the values of approximately 73.26 MPa in comparison to only about 34.85 MPa for the plain PLA and tensile modulus of approximately 2735.36 MPa in comparison to 1641.12 MPa for the plain PLA. The energy absorption of the biocomposites also showed promising results with a value of approximately 0.92 J/cm2 in comparison to only about 0.35 J/cm2 for the plain PLA. In addition, a scanning electron microscope (SEM) was used to scrutinize morphology of the PALF reinforced PLA biocomposites.

The Effect of Spent Bleach Earth on the Properties of Sintered Green Glass Ceramic Composite

The purpose of this study is to investigate the effect of spent bleach earth (SBE) loading on the properties of green glass ceramic (GGC) composite. GGC was prepared using SBE and recycled soda lime silicate (SLS) glass. SLS glass was crushed then sieved to approximately 45µm. These GGC composites were formed with different weight fraction of SBE loading (40, 45 and 55 wt.%) by uniaxial dry pressing and sintered at different sintering temperature (700 °C, 750 °C and 850 °C). The sintering temperatures were selected based on Tg of the glass which is around 416 °C. The GGC specimens were analyzed in terms of its physical properties (density, water absorption and porosity), phase presence (X-Ray diffraction) and sintered microstructure (scanning electron microscopy). X-Ray diffraction pattern indicated that cristobalite, quartz and wallastonite phases were formed during sintering. It was found that the GGC with 45 wt.% of SBE loading sintered at 850 °C produced minimum water absorption which was 4.01% accompanied by density of 2.12 g/cm3 and a porosity of 8.49%. This shows that GGC composite produced with considerable higher amount of waste loading able to obtain acceptable physical durability.

Effect of Carbon Particle Size and Content on the Mechanical and Thermal Properties of Recycled SLS Glass Composite

Glass-composite materials were prepared from the soda lime silicate (SLS) waste glass; ball clay and charcoal powder were fired to temperature of 850 °C as an effort for recycling waste glass. Various carbon contents, i.e., 1, 5, 10, 20 and 30 wt.% C were used to evaluate the effect of carbon contents on the hardness and thermal properties of glass composites. In addition, five different particles size (d0.5) of 1, 5, 20, 40 and 75 μm were used to observe the influence of particle size on the physical and mechanical properties of the glass composites. Phase analysis studies revealed the presence of quartz (ICDD: 00001-0649, 2θ = 25.6° and 35.6°), cristobalite (ICDD 00004-0379, 2θ = 22.0° and 38.4°) and wollastonite (ICDD 00002-0689, 2θ = 30.1° and 26.9°). The results showed that the optimised properties is at 1 wt.% of carbon content containing average pore size of 10 μm, with lowest porosity percentage of 1.76 %, highest Vickers microhardness of 4.6 GPa and minimum CTE. The percentage of porosity and hardness value also increased with reduction in carbon particle size.