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
    Mechanical properties of rCB-pigment masterbatch in rLDPE: the effect of processing aids and water absorption test
    (De Gruyter Brill, 2023)
    Muhamad Al-Haqqem Abdul Hadi
    ;
    Nor Azura Abdul Rahim
    ;
    Chew Kang Wei
    ;
    Teh Pei Leng
    ;
    Voon Chun Hong
    ;
    Wong Wee Chun
    Homogenization of pigment is the key to coloring a plastic product evenly. In this article, the tensile properties of recovered carbon black merge with low molecular weight lubricants and other compounding ingredients in the form of pigment masterbatch (PM) added in a recycled low-density polyethylene (rLDPE) resin were evaluated. The prepared masterbatch with the varying amount and types of processing aids (A and B) was first compounded using the heated two-roll mill. Subsequently, the manually mixed masterbatch in rLDPE was put through an injection molding machine for the shaping process to produce an rLDPE pigment masterbatch composite (PMC). The tensile test was performed on the samples to evaluate the mechanical properties of the PMC. Meanwhile, the melt flow index test was executed to justify the composite flow characteristics. Fourier-transform infrared spectroscopy analysis and scanning electron microscopy were also carried out to analyze the PM and PMC chemical properties and their constructed surface morphology. Besides, X-ray diffraction analysis was performed to determine the changes in degree of crystallinity before and after the water absorption test. The addition of PM in rLDPE has slightly increased the rLDPE matrix tensile properties. While, the usage of more processing aid B in the PMC has turned out to secure better tensile properties compared to the addition of higher amount of processing aid A in the PMC. Interestingly, the tensile properties of all composites after the water absorption test were enhanced, suggesting that a stronger bond was formed during the immersion period.
  • 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.
      2  24
  • 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  13
  • 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.
      21  8
  • Publication
    The effect of liquid silicone rubber content on the properties of filled and unfilled natural rubber latex/liquid silicone rubber blend (NRL/LSR)
    (American Institute of Physics Inc., 2022-05-18)
    Ming C.W.
    ;
    Teh Pei Leng
    ;
    Jalilah Abd Jalil
    ;
    Yeoh Cheow Keat
    ;
    Lim J.H.
    Polymer blend is known as the simplest method to obtain a new material by just blending two or more materials with suitable mixing technique. Most of the material engineers play their effort to improve the compatibility and miscibility of the blend components since this gives significant effect on the properties of the resulting materials. However, some of the creative engineers used the shortage of the immiscible blend material in the electronic application by inducing the double percolation with the aim to improve the electrical conductivity of the inherently insulating polymeric materials and at the same time conserve the attractive properties of the polymeric matrix. Herein, unfilled NRL/LSR and filled NRL/LSR with 7phr of GNP-SDS blend materials were prepared in order to investigate the effect of LSR content on the crosslink density, tensile properties, tear strength and electrical properties of the blend materials. It was found that the physical and mechanical properties of the materials declined with the increasing LSR content. Nevertheless, the modulus and the electrical properties of the filled NRL/LSR have been improved.
      2  2