Theses & Dissertations

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https://hdl.handle.net/20.500.14170/194

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Now showing 1 - 5 of 207
  • Publication
    The effect of conductive fillers and poly (Ethylene Glycol) diglycidyl ether on the properties of poly (Vinyl Chloride)/Poly (Ethylene Oxide) conductive films
    ( 2015)
    Siti Hajar Mohd Din
    In this research, the conductive films based on poly (vinyl chloride)/poly (ethylene oxide) (PVC/PEO) with conductive fillers like carbon black, polyaniline and polypyrrole were prepared by solution casting method at the speed of 400 rpm. The composition of 5, 10, 15, 20, 25, 30 wt % of filler loading were incorporated in PVC/PEO: 50/50 blends. The tensile properties, morphology, Fourier Transform Infrared spectroscopy (FTIR) analysis, electrical conductivity and thermogravimetric analysis (TGA) were studied. Poly (vinyl chloride)/poly (ethylene oxide)/carbon black (PVC/PEO/CB) at different compositions were prepared. The tensile strength and modulus of elasticity were increased until up to 25 wt% with the addition of the CB by 25.33% and 16.66% respectively. However, at 30 wt% of CB loading, tensile strength and tensile modulus were slightly decreased to 15.87% and 10.7% respectively. The thermal stability and electrical conductivity of PVC/PEO/CB conductive films are increased with the increasing of CB loading. In another system, polyaniline (PAni) filled in PVC/PEO blends explained that the increasing amount of PAni content reduced the 61.24 % of tensile strength and 20.44 % of modulus of elasticity but showed positive increment on electrical conductivity and thermal stability of PVC/PEO/PAni conductive films. The effect of poly (ethylene glycol) diglycidyl ether (PEGDE) on PVC/PEO/CB conductive films decreased 55.65 % of tensile strength and thermal stability but increased 6.45% modulus of elasticity and electrical conductivity. However, addition of PEGDE has increased 1.21% of tensile strength, 6.45% of modulus of elasticity and electrical conductivity but decreased the thermal stability of PVC/PEO/PAni conductive films. The morphology of soaked conductive films indicated that the addition of PEGDE imparted better filler dispersion to the PVC/PEO/CB and PVC/PEO/PAni conductive films. The physical interaction between PVC/PEO blends, PEGDE and conductive filler presented in conductive films was identified by FTIR spectroscopy. In the study, polypyyrole (PPy) filled PVC/PEO conductive films at 15 wt% with the addition of PEGDE exhibited better composition in terms of higher electrical conductivity and thermal stability. However, the tensile strength and modulus of elasticity was lower compared to PVC/PEO/CB and PVC/PEO/PAni conductive films with and without the presence of PEGDE.
  • Publication
    Fabrication and characterization of hybrid microwave assisted sintering Sn-0.7Cu + 1.0wt.% Si₃N₄ composite solder
    ( 2015)
    Flora Somidin
    One of the leading choices in upgrading the properties of existing lead-free solder alloys is by composite technology approach, whereby high technical ceramic particles can be added into the solder alloy matrix. Accordingly, Sn-0.7Cu + 1.0wt.% Si₃N₄ composite solder was synthesized using powder metallurgy routes which consist of blending, compaction and sintering. This research introduced a hybrid microwave assisted sintering process which can sinter ceramic-reinforced composite solder at approximately 185˚C within 2 minutes without holding time and protective inert gas. In order to evaluate the compatibility of hybrid microwave assisted sintering approach in ceramic-reinforced composite solder development, a detailed comparison of the process and properties of conventionally sintered and microwave sintered samples of Sn-0.7Cu + 1.0wt.% Si₃N₄ composite solder was performed. Identical sintering temperature at 185 ˚C was used for both types of sintering, in which conventional sintering was performed using a tube furnace in an argon atmosphere for 2 hours. The monolithic Sn-0.7Cu solder sample was also synthesized as control sample in a similar way. Hybrid microwave assisted sintering method showed significant advantages in processing compared to conventional sintering method, such as rapid heating rate, shortened sintering time, less energy consumption and much less expensive equipment. The influence of different sintering methodologies on Sn-0.7Cu + 1.0wt.% Si₃N₄ bulk solder sample were investigated based on the density, porosity, microhardness, microstructures, wettability and intermetallic compound thickness on Cu-substrate. It was noted that microwave sintering method can densify the Sn-0.7Cu + 1.0wt.% Si₃N₄ composite bulk solder green compact in a short time, however, conventional sintered sample showed better density and porosity. Interestingly, finer and well-distributed precipitates were observed in microwave sintered samples. This has led to higher microhardness performance observed in microwave sintered sample (12.0 ± 0.2 HV) compared to the conventionally sintered sample (11.2 ± 0.1 HV). The wettability performance of Sn-0.7Cu + 1.0wt.% Si₃N₄ composite solder on Cu-substrate was slightly reduced with microwave sintering approach, however, insignificant difference of intermetallic compound thickness was observed in both microwave sintered and conventionally sintered samples. Overall, hybrid microwave assisted sintering showed better processing with promising properties on ceramic-reinforced Sn-0.7Cu + 1.0wt.% Si₃N₄ composite solder.
  • Publication
    Properties of chicken feather fiber/tyre dust hybrid composition filled recycled high density polyethylene composites
    ( 2014)
    Emy Aizat Azimi
    The composites of chicken feather fiber (CFF)/recycled high density polyethylene (RHDPE), tyre dust (TD)/recycled high density polyethylene (R-HDPE), and hybrid fillers composite between chicken feather fiber (CFF)/tyre dust (TD)/recycled high density polyethylene (R-HDPE) were studied. Both composites were prepared by using Brabender Plasticoder at 160 °C with rotor speed of 50 of rpm. The effect of CFF, TD content and various type of compatibilizer on tensile properties, mass swell percentage, morphological properties, spectroscopy infrared and XRD characterization of R-HDPE/CFF, R-HDPE/TD and R-HDPE/TD/CFF composites were investigated. The compatibilizer used in this study was maleic anhydride (MAH), phthalic anhydride (PA), and polyethylene grafted maleic anhydride (PE-g-MAH). The increasing of filler loading leads to decreased the tensile strength and elongation at break of R-HDPE/CFF and R-HDPE/TD composite while the modulus of elasticity and interparticle spacing (d) was increased. It was also found that increasing of CFF content in the composition of TD/CFF of hybrid filler decreased the tensile strength, elongation at break while the modulus of elasticity and interparticle spacing (d) was increased. The incorporation of MAH, PA and PE-g-MAH as compatibilizer in R-HDPE/TD/CFF hybrid filler composites exhibit an improvement in the tensile strength and modulus of elasticity whereas decreased in the elongation at break, mass swell percentage and interparticle spacing (d). Scanning electron microscopy (SEM) successfully illustrates the dispersion of fillers in the matrix. Scanning electron microscopy (SEM) also show that the incorporation of both compatibilizer improved interfacial adhesion and tensile fracture between R-HDPE and TD/CFF. FTIR analysis proved the presence of MAH, PA and PE-g-MAH in the R-HDPE/TD/CFF hybrid composites.
  • Publication
    Interlayer mixing in lithium nickel manganese cobalt oxide cathode materials for rechargeable lithium batteries
    ( 2014)
    Tan Tze Qing
    Composition of LiNi1/3Mn1/3Co1/3O2 and its analogous Li[(Ni0.5Mn0.5)1-xCox]O2 were prepared by conventional solid state method to evaluate the effect of reducing cobalt contents to the layered rock salt-type cathode materials. Structural analysis using Rietveld refinement of conventional XRD data revealed that the amount of cobalt contents is highly correlated to their structural stability. Solid solution limit for phasepure samples that were prepared is about x > 0.2 for Li[(Ni0.5Mn0.5)1-xCox]O2. The amount of interlayer mixing increased for samples contain 20% or less cobalt contents. The results showed that the minimum amount of interlayer mixing that could be achieved is about 3.8% for the composition of LiNi0.4Mn0.4Co0.2O2 that was prepared at 950 oC in oxygen compared to LiNi1/3Mn1/3Co1/3O2 which is about 2%. However, the amount of interlayer mixing varies as a function of temperatures and conditions. Systematic investigation have been done to optimize refinement parameters and to validate structural model based on LiCoO2 as a standard. On the other hand, the initial charge and discharge capacities during battery cycling for LiNi0.4Mn0.4Co0.2O2 is relatively high which recorded ~323 mAh g-1 and ~229 mAh g-1 respectively. But it has high irreversible capacity loss after a few cycles that are probably due to structural instability during charge and discharge.
  • Publication
    Potential of LUSI Mud as geopolymer material for artificial lightweight aggregate
    ( 2015)
    Rafiza Abd Razak
    The abundant amount of LUSI (LU-Lumpur, SI-Sidoarjo) mud that began erupting near the Banjarpanji-1 exploration well in Sidoarjo, East Java, Indonesia need to convert onto useful and valuable alternatives. Geopolymer becomes an attractive research due to improving the concrete properties, increased durability, improved performance, lower cost and preserves the environment. Geopolymer is a term used to describe inorganic polymers based on aluminosilicates that can be produced by synthesizing pozzolanic compounds or aluminosilicate source materials with highly alkaline solutions. The high demand for lightweight aggregate in concrete encourages this research to explore new material of LUSI mud to be used as artificial lightweight aggregate with excellent properties and performance in concrete application. This study will focus on utilizing the LUSI mud as an artificial lightweight geopolymer aggregate (ALGA) to be used in lightweight concrete. Sintering method has been choosen in this study due to better properties produced and commercial priority. Production processes include design, mixing of LUSI mud and alkaline activator (sodium hydroxide, NaOH + sodium silicate, Na2SiO3), pelletizing and sintering process. There are three parameters that influence aggregate produced, i) sintering temperature; ii) NaOH molarity; iii) LUSI mud/alkaline activator ratio and Na2SiO3/NaOH ratio. The characterization of LUSI mud and properties of ALGA have been done by using Particle Size Analyzer (PSA), X-Ray Flourescence (XRF), X-Ray Diffraction (XRD), Scanning Electron Microscope (SEM) and Fourier Transform Infrared (FTIR). The results showed that the sintering temperature of 950 °C, NaOH molarity of 12M, LUSI mud/alkaline activator ratio of 1.7 and Na2SiO3/NaOH ratio of 0.4 gives the optimum Aggregate Impact Value (AIV) of 15.42% with low density of 1100 kg/m3 and water absorption (4.7%).