Teh Pei Leng
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Preferred name
Teh Pei Leng
Official Name
Teh. Pei Leng
Alternative Name
Leng, T. Pei
Leng, T. P.
Teh, P. L.
Leng, Teh Pei
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Scopus Author ID
6701800182

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  • Publication
    Effect of solvent on mechanical and physical properties of PMMA/Sic composite films
    ( 2024-12)
    Auni Fakhira Che Baharudin
    ;
    Lim Bee Ying
    ;
    Voon Chun Hong
    ;
    Teh Pei Leng
    ;
    Tan Soo Jin
    The selection of solvent in solution casting is crucial as it may affect the morphology and properties of the resulting composite films. In this study, the effect of solvent on the properties of poly(methyl methacrylate)/silicon carbide (PMMA/SiC) composite films was investigated. By using acetone, the solution casting was carried out at various solvent-to-solid (S/S) ratio, from 4:1 to 10:1 at room temperature. It was found that the increasing S/S ratio enhanced the tensile strength and modulus of elasticity of pristine PMMA films but deteriorated its elongation at break, up to 8:1 ratio. The crystallinity of the PMMA films was found to increase with S/S ratio, as confirmed by the higher peak intensity in X-Ray Diffraction (XRD) patterns and the SEM micrographs. In the second part of the study, by using S/S ratio of 8:1, the nano sized SiC (0.25 wt%) was added as a filler into PMMA and toluene with different ratio was added as a secondary solvent. The addition of SiC has increased the tensile strength and modulus of elasticity of PMMA/SiC but decreased its elongation at break. However, the presence of toluene reduced the tensile strength of the PMMA/SiC composite films and resulting in rougher tensile fracture surfaces as shown in SEM micrographs. The toluene with nonpolar nature had affected the distribution of SiC in PMMA. It can be concluded that the properties of the PMMA composites films can be tailored according to the needs of applications.
  • Publication
    Effect of printing parameters on tensile, dynamic mechanical, and thermoelectric properties of FDM 3D printed CABS/ZnO composites
    ( 2018-03-22)
    Yah Yun Aw
    ;
    Yeoh Cheow Keat
    ;
    Mohd Asri Idris
    ;
    Teh Pei Leng
    ;
    Khairul Amali Hamzah
    ;
    Shulizawati Aqzna Sazali
    Fused deposition modelling (FDM) has been widely used in medical appliances, automobile, aircraft and aerospace, household appliances, toys, and many other fields. The ease of processing, low cost and high flexibility of FDM technique are strong advantages compared to other techniques for thermoelectric polymer composite fabrication. This research work focuses on the effect of two crucial printing parameters (infill density and printing pattern) on the tensile, dynamic mechanical, and thermoelectric properties of conductive acrylonitrile butadiene styrene/zinc oxide (CABS/ZnO composites fabricated by FDM technique. Results revealed significant improvement in tensile strength and Young's modulus, with a decrease in elongation at break with infill density. Improvement in dynamic storage modulus was observed when infill density changed from 50% to 100%. However, the loss modulus and damping factor reduced gradually. The increase of thermal conductivity was relatively smaller compared to the improvement of electrical conductivity and Seebeck coefficient, therefore, the calculated figure of merit (ZT) value increased with infill density. Line pattern performed better than rectilinear, especially in tensile properties and electrical conductivity. From the results obtained, FDM-fabricated CABS/ZnO showed much potential as a promising candidate for thermoelectric application.
  • Publication
    The effect of the GNP-SDS loadings on the properties of the NRL/GNP-SDS composites
    ( 2020-07-09)
    Che W.M.
    ;
    Teh Pei Leng
    ;
    Jalilah Abd Jalil
    ;
    Yeoh Cheow Keat
    Stretchable conductive polymer composites (CPC) are fabricated by incorporating the conductive particles into the polymer matrix. In this paper, CPC was fabricated by incorporating the sodium dodecyl sulfate (SDS) modified graphene nanoplatelet (GNP) into natural rubber latex (NRL) by varying loading from 0phr to 9phr using a simple mechanical stirring method. The effect of the GNP-SDS loadings on the properties of the composites were study by investigated the crosslink density, tensile properties, morphology of the tensile fracture surface and electrical conductivity. The crosslink density of the composites shows a decreased trend. Then, due to the well dispersed GNP-SDS, the tensile strength increased but decreased at high filler loading caused by the agglomeration issue. The tensile modulus also increased with increasing filler loading due to the intrinsic high modulus of GNP and the reduction of chain mobility. However, the electrical properties of the composites improved as GNP-SDS loading increased and achieved a percolation threshold at 7phr.
  • Publication
    Fabrication of polymethyl methacrylate composite films with silanized SiC nanoparticles
    ( 2025-01)
    Mohamad Azrol Bin Azmi
    ;
    Lim Bee Ying
    ;
    Voon Chun Hong
    ;
    Phey Yee Foong
    ;
    Teh Pei Leng
    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
    Comparison between natural rubber, liquid natural rubber, and recycled natural rubber as secondary matrix in epoxy/natural rubber/graphene nano-platelet system
    (Springer International Publishing, 2023)
    K. W. Kam
    ;
    Teh Pei Leng
    ;
    Yeoh Cheow Keat
    A comparison is made between the effects of natural rubber (NR), liquid natural rubber (LNR), and recycled natural rubber (rNR) in the filled epoxy systems on the physical, mechanical, thermal, and electrical performances of filled epoxy systems. The results show that flexural strength and modulus values were improved. The toughness properties of the filled epoxy system were enhanced with NR phases (72 MPa, 2317 MPa, 4.2 MPa. m1/2), as compared to those with LNR (55 MPa, 2100 MPa, 3.2 MPa. m1/2) and rNR (52 MPa, 2000 MPa, 2.3 MPa. m1/2) at 5 vol.%. Scanning electron micrograph (SEM) analysis revealed that the particle sizes of NR phases dispersed within the epoxy matrix were smaller and more uniform (0.29-1.65 μm) as compared to those with LNR (0.64-3.57 μm) and rNR (≥250 μm) phases. The incorporation of NR, LNR, and rNR phases improved the thermal stability of the filled system. This is attributed to more heat energy being needed to overcome good interfacial bonding between epoxy matrices and the small NR phases. X-ray diffraction analysis results showed that the filled epoxy/NR/GNP system has higher 2θ values, indicating that d-spacing in GNP nano-fillers has the closer distance. Electrical bulk conductivity values of filled epoxy/NR/GNP systems were the highest, 4.50 x 10-3 1/Ω. cm at 20 vol.%. Small NR phases acted as elastomer spacers, which provided better GNP packing efficiency and realigned the GNP nano-fillers to form more effective conductive pathways for electron transport.
  • Publication
    Microwave welding of thermoplastic using silicon carbide nanowhiskers as susceptor effect of heating duration
    ( 2024-06)
    Phey Yee Foong
    ;
    Voon Chun Hong
    ;
    Lim Bee Ying
    ;
    Teh Pei Leng
    ;
    Yeoh Cheow Keat
    ;
    Mohd Afendi Rojan
    ;
    Nor Azizah Parmin
    ;
    Subash Chandra Bose Gopinath
    ;
    Foo Wah Low
    ;
    Muhammad Kashif
    ;
    Nor Azura Abdul Rahman
    ;
    Sam Sung Ting
    ;
    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.
      10  47
  • Publication
    Effect of infill pattern on mechanical properties of 3D printed PLA and cPLA
    ( 2020-11-24)
    Yeoh Cheow Keat
    ;
    Cheah, Chee Son
    ;
    Pushpanathan, Raguvaran
    ;
    Song, Cheah Chie
    ;
    Tan, Mei Ai
    ;
    Teh Pei Leng
    PLA are the most sustainable alternatives and can fit in a wide-range of applications of electronics, nonwoven fabrics and food packaging. With these PLA's adaptability and suitability in many techniques of production such as injection moulding, extrusion, and blow moulding, PLA has become high interest in the production process. Besides, PLA as a thermoplastic polyester that mostly obtained from renewable materials [1]. Infill patterns can affect the mechanical properties of 3D printed PLA and cPLA. PLA with zig zag infill pattern has higher tensile strength of 23.409 MPa compared to PLA with grid and concentric infill pattern. Meanwhile, cPLA with grid infill pattern has higher tensile strength of 30.5638 MPa compared to cPLA with concentric and zig zag infill pattern. By using the suitable infill pattern parameter, the 3D printed PLA and cPLA can have good mechanical properties and can be applied in packaging, pharmaceuticals, textiles, automotive, biomedical and tissue engineering. It has been widely investigated for biomedical applications due to its biodegradability and biocompatibility.
      4  19
  • Publication
    Effect of dispersibility of graphene nanoplatelets on the properties of natural rubber latex composites using sodium dodecyl sulfate
    (Walter de Gruyter GmbH, 2022-01-01)
    Che W.M.
    ;
    Teh Pei Leng
    ;
    Yeoh Cheow Keat
    ;
    Jalilah Abd Jalil
    ;
    Lim Bee Ying
    ;
    Rasidi M.S.M.
    Natural rubber latex/graphene nanoplatelet (NRL/GNP) composites containing GNP-pristine and GNP-SDS were prepared by a simple mechanical mixing method. The main objective was to study the effect of dispersibility of GNP on the properties in NRL. X-ray diffraction confirmed the adsorption of sodium sulfate dodecyl (SDS) on the GNP surface. The results showed that high filler loading diminished the physical and mechanical properties of the composites but successfully endured to satisfy electrical conductivity to the NRL/GNP composites. Besides, the SDS surfactant-filled system demonstrated better physical, tensile, electrical, and thermal stability properties than the GNP-pristine. The intercalated and dispersed GNP-SDS increased the number of routes for stress and heat transfer to occur and facilitated the formation of conductive pathways as well, leading to the improvement of the properties as compared to NRL/GNP-pristine composites. However, as the GNP-SDS loading exceeded 5 phr, the GNP-SDS localized in the interstitial layer of NRL, restricted the formation of crosslinking, and interfered with the strain-induced crystallization ability of the composites.
      3
  • 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.
    ;
    Teh Pei Leng
    ;
    Yeoh C.K.
    ;
    Nor Azura Abdul Rahim
    ;
    Wong W.C.
    ;
    Voon Chun Hong
    ;
    Mohamed Rasidi M.S.
    ;
    Lim Bee Ying
    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.
      1  33
  • Publication
    The influence of liquid silicone rubber on the properties of polyurethane elastomer/liquid silicone rubber/graphene nanoplatelets stretchable conductive materials
    ( 2022-11-01)
    Heng C.W.
    ;
    Teh Pei Leng
    ;
    Nor Azura Abdul Rahim
    ;
    Yeoh C.K.
    This work reports the influence of liquid silicone rubber (LSR) as a secondary matrix in the polyurethane elastomer (PUE)/LSR/graphene nanoplatelets (GnPs) stretchable conductive materials. PUE was prepared by mixing with diphenylmethane-4,4-diisocyanate (MDI) and 1,4 butanediol (BDO). The content of LSR varied from 0 to 50 vol.% at fixed 1.0 vol.% of graphene nanoplatelets (GnPs) as a conductive filler. Liquid silicone rubber was used as the secondary immiscible phase to localize GnPs into a path in the primary phase in order to obtain higher electrical conductivity value. The tensile strength of the PUE/LSR/GnPs decreased with increasing LSR content, while the tear strength shows the optimum value at 10 vol.% of LSR. The incorporation of 20 vol.% of silicone rubber has proven to enhance the thermal stability of the blends.
      4  11