Teh Pei Leng
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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
    Investigation of blend ratios on physical, mechanical, and electrical properties of stretchable conductive ternary blend NRLVSR materials unfilled and filled system
    ( 2025-01)
    Wern-Ming Che
    ;
    Teh Pei Leng
    ;
    Jalilah Abd Jalil
    ;
    Yeoh Cheow Keat
    ;
    Mohamad Nur Fuadi Bin Pargi
    Stretchable conductive material has garnered significant attention in recent years since it offers both electrical conductivity and the ability to undergo significant deformation without losing its conductivity. Herein, NRL/VSR blend materials were prepared with varying blend ratios, both with and without GNP-SDS, using a simple mechanical stirring method. The main objective was to investigate the influence of blend ratios on the physical, mechanical, and electrical properties of the unfilled and filled blend systems. The findings revealed that the addition of VSR had a detrimental effect on the crosslink density of the resulting materials, leading to a negative impact on their mechanical properties. However, a contrasting observation was made regarding the electrical properties. The introduction of VSR induced the formation of a double percolation structure in the immiscible NRL/VSR blend. This double percolation structure facilitated the creation of a conductive network within the blend, which significantly improved its electrical properties by approximately 263.85 folds.
  • Publication
    Effect of infill pattern on mechanical properties of 3D printed PLA and cPLA
    ( 2020-11-24)
    Yeoh C.K.
    ;
    Cheah C.S.
    ;
    Pushpanathan R.
    ;
    Song C.C.
    ;
    Tan M.A.
    ;
    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.
  • Publication
    Mechanical properties and thermal and electrical conductivity of 3D printed ABS-copper ferrite composites via 3D printing technique
    ( 2022-01-01)
    Hamzah K.A.
    ;
    Yeoh C.K.
    ;
    Mazlee Mohd Noor
    ;
    Teh Pei Leng
    ;
    Aw Y.Y.
    ;
    Sazali S.A.
    ;
    Wan Mohd Arif W Ibrahim
    This study examines the effect of particulate reinforcement on the mechanical properties of 3D printed acrylonitrile–butadiene–styrene (ABS). Copper ferrite (CuFe2O4) as a reinforcer with various loadings was used to print ABS composite specimen, namely, 8, 11 and 14 wt%. Mechanical testing such as tensile test and hardness test was performed on the printed samples. Specimens with 14 wt% of CuFe2O4 showed a 135% increase in tensile strength compared to the pure ABS specimens. Specimens printed with 14 wt% of CuFe2O4 are 14% harder compared to the pure ABS specimens. Thermal conductivity increased 93% for specimen loaded with 14 wt% reinforcer. Electrical conductivity shows a one-order increase for composite specimen compared to control specimen.
  • Publication
    Effect of solvent to matrix weight ratio and stearic acid treatment on the mechanical properties of Poly (methyl methacrylate)/ palm kernel shell composites
    ( 2021-07-21)
    Lim Bee Ying
    ;
    Voon Chun Hong
    ;
    Lye S.F.
    ;
    Teh Pei Leng
    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
    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
    ( 2021-09-01)
    Ka Wei K.
    ;
    Teh Pei Leng
    ;
    Yeoh Cheow Keat
    ;
    Hakimah Osman
    ;
    Sullivan M.
    ;
    Voon Chun Hong
    ;
    Lim Bee Ying
    ;
    Mohamad Syahmie Mohamad Rasidi
    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
    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.
  • 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
    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
    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.
  • 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.