Now showing 1 - 10 of 16
  • Publication
    Microwave welding of thermoplastic using silicon carbide nanowhiskers as susceptor effect of heating duration
    ( 2024-06)
    Phey Yee Foong
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    ; ; ; ; ; ; ;
    Foo Wah Low
    ;
    Muhammad Kashif
    ;
    Nor Azura Abdul Rahman
    ;
    ;
    Veeradasan Perumal
    Microwave welding is becoming more popular than conventional joining methods due to its advantages such as rapid and localised heating as well as applicable to components with complicated geometry. Previously reported susceptor, such as carbonaceous materials and conductive polymers, are toxic and the welding process involving these susceptors is time-consuming. Because of its exceptional microwave absorption and biocompatibility, silicon carbide nanowhiskers (SiCNWs) was employed as the microwave susceptor for microwave welding. Microwave welding in this study comprises of only three simple steps: SiCNWs suspension preparation, SiCNWs application and microwave heating. The weld strength of welded joint was then characterised using tensile test and energy dispersive x-ray spectroscopy equipped scanning electron microscopy (EDS-SEM) to study its mechanical properties and cross-section microstructure. The influence of microwave irradiation time was studied in this study, and it is found that the weld strength rose with the extension of microwave irradiation time, until a maximum weld strength of 1.61 MPa was achieved by 17 s welded joint. The development of SiCNWs reinforced PP nanocomposite welded joint layer is responsible for the enhanced weld strength. Prolonged heating duration may also result in flaws such as void formation at the welded joint, which subsequently lowered the weld strength to 0.60 MPa when the heating duration was extended to 20 s. In sum, a strengthen welded joint can be formed with rapid microwave heating under the proper control of heating duration.
  • Publication
    Preparation and Characterization of Tensile Properties of PMMA/SiC Nanowhiskers Nanocomposite Films: Effect of Filler Loading and Silane Treatment
    ( 2023-10-01) ; ;
    Lee L.Y.
    ;
    ;
    Foong P.Y.
    The preparation of nanocomposites through melt mixing was challenging as the nanofillers tend to form agglomeration. The silicon carbide nanowhiskers (SiCNWs) filled poly (methyl methacrylate) (PMMA) thin film in this study was prepared by means of solution casting. Acetone with low toxicity was used as solvent to dissolve the PMMA pellets. A coupling agent, silane was used to enhance the properties of composite films. Besides, the untreated and treated SiCNWs were filled into PMMA matrix, respectively with the filler loading varied from 0.2 to 0.8 wt%. The universal testing machine was used to investigate the tensile properties of composites. It was found out that the tensile strength of the PMMA was reduced in the presence of SiCNWs. However, the tensile strength had increased with the rise of filler loading. At 0.8 wt% of SiCNWs, the composites’ tensile strength was comparable to virgin PMMA. Meanwhile, the SiCNWs had reduced the elongation at break but increased the elastic modulus of PMMA/SiCNWs nanocomposite films. In addition, silane surface treatment on SiCNWs had improved the tensile strength and ductility but lowered the elastic modulus of the nanocomposites. The improvement was due to the enhancement of interfacial adhesion between SiCNWs and PMMA.
  • Publication
    The effect of coated calcium carbonate using stearic acid on the recovered carbon black masterbatch in low-density polyethylene composites
    ( 2023-01-01)
    Leow V.J.
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    Yeoh C.K.
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    ;
    Wong W.C.
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    ;
    Mohamed Rasidi M.S.
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    This research focuses on recycling rubber tire waste through pyrolysis to produce recovered carbon black (rCB). The rCB is combined with recycled low-density polyethylene (rLDPE), calcium carbonate (CaCO3), fatty acid, metallic stearate, and polyethylene (PE) wax to create an rCB masterbatch for household packaging. Surface modification of CaCO3 particles using stearic acid improves the compatibility with LDPE. The study investigates mechanical properties, morphology, melt flow index (MFI), X-ray diffraction, and thermogravimetric analysis in three systems: uncoated, coated, and a hybrid combination of coated and uncoated CaCO3 in LDPE/rCB masterbatch composites. The coated system demonstrates higher mechanical properties and improved compatibility between CaCO3 and LDPE. All three systems exhibit enhanced thermal stability and MFI compared to virgin LDPE, with the coated system showing the most significant improvement. The study showcases the potential of LDPE/rCB masterbatch composites for household packaging, with the coated system displaying the optimum performance across various characteristics.
  • Publication
    Fabrication of polymethyl methacrylate composite films with silanized SiC nanoparticles
    ( 2025-01)
    Mohamad Azrol Bin Azmi
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    ; ;
    Phey Yee Foong
    ;
    The properties of polymeric composites have often been altered with the incorporation of fillers. In this study, the poly(methyl methacrylate) (PMMA) was filled with silicon carbide nano-particles (SiC). The PMMA/SiC composite films were prepared through solution casting by using acetone as solvent. The different loading of SiC ranging from 0.25 wt% to 1.00 wt% were incorporated into the PMMA matrix. The effect of SiC loading and silane coupling agent on PMMA/SiC composite films in terms of mechanical, physical, and morphological properties was investigated. It was found that the increasing SiC loading and the silane treatment had increased the tensile strength and Young’s modulus but reduced the elongation at the break of PMMA/SiC composite films. At 0.75 wt% of silanized SiC, the tensile strength of the composite films was found to increase by 25 % from 30 to 37.5 MPa as compared to the virgin PMMA. Besides, the hardness of composite films was also increased with SiC loading and silane treatment. The presence of 1.00 wt% silanized SiC had increased 21.7% the hardness of the virgin PMMA, resulting in the increase of Shore A value from 69 to 84. By using silane treatment, better filler-matrix interaction was established as smoother fracture surfaces were observed through SEM micrographs and higher d-spacing was found in X-ray diffraction (XRD) patterns. The PMMA/SiC composite films prepared were suitable to be used in sporting goods, additive manufacturing, and environmental and protective coatings.
  • Publication
    Effect of solvent to matrix weight ratio and stearic acid treatment on the mechanical properties of Poly (methyl methacrylate)/ palm kernel shell composites
    In this study, poly (methyl methacrylate)/palm kernel shell (PMMA/PKS) composites were prepared by solution casting. The effect of solvent to matrix (S/M) weight ratio and stearic acid (SA) treatment on PMMA/PKS composites were studied. PMMA pellets were dissolved and PKS powders were dispersed into acetone, separately. PMMA solution and PKS suspension were then mixed in ultrasonic bath. The mixture was then poured into a glass petri dish to evaporate acetone at room temperature and finally PMMA/PKS composite thin film was obtained. PMMA/PKS composites were characterized by using SEM and were subjected to tensile test. It was found that tensile strength, modulus of elasticity of composite increased but elongation at break decreased with the increasing S/M ratio and with SA treatment. The improvement of the mechanical properties was due to the improved interfacial bonding following the SA treatment and the formation of crystallized PMMA domain in the composite with the increasing S/M ratio. SEM images revealed even fracture surfaces as S/M increased and with the application of SA treatment that indicate better matrix-filler adhesion. It can be concluded that S/M increment and SA treatment improved mechanical properties of PMMA/PKS composite.
  • Publication
    A comparative study of microwave welding using multiwalled carbon nanotubes and silicon carbide nanowhiskers as microwave susceptors
    ( 2024-10)
    Phey Yee Foong
    ;
    ; ; ; ; ; ; ;
    Foo Wah Low
    ;
    Muhammad Kashif
    ;
    Nor Azura Abdul Rahman
    ;
    ;
    Veeradasan Perumal
    Recently, microwave welding has arisen as an advanced joining method due to its versatility and rapid heating capabilities. Among others, microwave susceptors play a crucial role in microwave welding, as different classes of microwave susceptors have distinct microwave heating mechanisms. In this work, polypropylene (PP) was utilized as a thermoplastic substrate and two types of microwaves susceptors, namely multiwalled carbon nanotubes (MWCNTs) and silicon carbide nanowhiskers (SiC NWs), were studied for microwave welding. The susceptor was first dispersed in acetone to form susceptor suspension. Next, the susceptor suspension was deposited onto the targeted area on substrate and paired with another bare PP substrate. The paired sample was then exposed to 800 W microwave radiation in a microwave oven. Afterward, the welded joint was evaluated using a tensile test and scanning electron microscopy to determine its joint strength and cross-section microstructure. The results showed that the joint strength increased as the heating duration increased. The welded joint formed using MWCNTs achieved a maximum strength of 2.26 MPa when 10 s was used, while the SiC NWs-formed welded joint achieved a maximum strength of 2.25 MPa at 15 s. This difference in duration in forming a complete welded joint can be attributed to the higher microwave heating rates and thermal conductivity of MWCNTs. However, increasing the heating duration to 20 s caused severe deformation at the welded joint and resulted in low joint strength. Overall, this study highlights the significance of understanding the microwave heating mechanism of different susceptors and provides essential insight into the selection of a microwave susceptor for microwave welding.
  • Publication
    Comparison study: The effect of unmodified and modified graphene nano-platelets (GNP) on the mechanical, thermal, and electrical performance of different types of GNP-filled materials
    Graphene nano-platelet (GNP) nano-fillers were successfully covalently functionalized with carboxylic and epoxide groups as proven by Fourier-transform infrared spectroscopy. This paper reports the effect of unmodified and modified GNP nano-fillers on the mechanical, thermal, and electrical performance of GNP-filled materials. The results show that the mechanical properties of GNP-filled materials were enhanced with a modified GNP nano-filler. Among the GNP-filled materials, the modified epoxy/NR/GNP compatibilized material shows higher flexural and toughness properties. The modified GNP nano-filler has reduced the thermal stability of the modified compatibilized material. This is because the oxygen-containing groups (C–O–C and –COOH) on the surfaces of modified GNP nano-fillers have lower thermal stability; which accelerates the thermal decomposition of the modified material. Modified compatibilized material shows higher electrical conductivity than the unmodified compatibilized material. X-ray diffraction results proved that d-spacing of modified GNP nano-fillers in modified compatibilized material was shortest when compared to unmodified GNP nano-fillers in unmodified compatibilized material, thus, allowing more electrons to travel at a faster rate through the conductive pathways.
  • Publication
    Rheological and thermal properties of palm kernel shell filled low density polyethylene composites
    The palm kernel shell (PKS) filled low density polyethylene (LDPE) composites were prepared by Z-blade mixer at temperature of 180 °C and rotor speed of 50 rpm. The effects of PKS loading and different types of chemical modifications on the rheological and thermal properties of the composites were studied. Chemical modification such as poly(ethylene-co-acrylic acid) (PEAA), acrylic acid (AA), 3- aminopropyltriethoxysilane (3-APE), coconut oil coupling agent (COCA) and ecodegradant were used in this study. The addition of PKS into LDPE matrix changed the rheological and thermal properties of the composites. The results showed that increasing PKS loading had decreased the melt flow index (MFI) values and non-Newtonian index but increased the melt consistency, viscosity and activation energy of the LDPE/PKS composites. The increasing temperature had increased the MFI values of composites. The viscosity of composites that was generated from capillary rheometer decreased with rise of temperature. The apparent shear stress of the composites increased with apparent shear rate and PKS loading. The composites with addition of PEAA, AA, COCA and eco-degradant showed higher MFI values but the composites treated with 3-APE exhibited lower MFI values than untreated composites. The activation energy for the composites with PEAA and 3-APE decreased, whereas the activation energy for the composites with AA, COCA and eco-degradant increased as compared to composites without chemical modifications. The composites with eco-degradant gave lowest viscosity, thus eased the composite processing at high filler loading. The thermal properties of composites showed that addition of PKS had decreased the onset temperature and the total weight loss of composites. The chemical modifications had increased the thermal stability of composites, whereas higher onset temperature and lower total weight loss at high temperature were observed. The FTIR spectra of composites showed that the functional groups of the composites changed with chemical modification.
  • Publication
    Preparation and characterization of tensile properties of PMMA-SiC nanowhiskers nanocomposite films: effect of filler loading and silane treatment
    ( 2023-10) ; ;
    L. Y. Lee
    ;
    ;
    P. Y. Foong
    The preparation of nanocomposites through melt mixing was challenging as the nanofillers tend to form agglomeration. The silicon carbide nanowhiskers (SiCNWs) filled poly (methyl methacrylate) (PMMA) thin film in this study was prepared by means of solution casting. Acetone with low toxicity was used as solvent to dissolve the PMMA pellets. A coupling agent, silane was used to enhance the properties of composite films. Besides, the untreated and treated SiCNWs were filled into PMMA matrix, respectively with the filler loading varied from 0.2 to 0.8 wt%. The universal testing machine was used to investigate the tensile properties of composites. It was found out that the tensile strength of the PMMA was reduced in the presence of SiCNWs. However, the tensile strength had increased with the rise of filler loading. At 0.8 wt% of SiCNWs, the composites’ tensile strength was comparable to virgin PMMA. Meanwhile, the SiCNWs had reduced the elongation at break but increased the elastic modulus of PMMA/SiCNWs nanocomposite films. In addition, silane surface treatment on SiCNWs had improved the tensile strength and ductility but lowered the elastic modulus of the nanocomposites. The improvement was due to the enhancement of interfacial adhesion between SiCNWs and PMMA.
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  • Publication
    Synthesis and preparation of metal oxide powders
    In recent years, metal oxide, especially in the form of powders, is extensively studied owing to their unique and novel properties. In this regard, this chapter provides a thorough description of current advances on the synthesis and preparation of metal oxide powders. The chapter begins with the introduction and motivation of the preparation of synthetic metal oxide powders. This is followed by the description of the synthesis and preparation method of metal oxide powders, which can be categorized into chemical methods, physical methods, and biological methods. Several important methods under each category were described with examples. This chapter ends with concluding remarks with views on the recent progress and future challenges of metal oxide powders research.