Now showing 1 - 10 of 19
  • Publication
    Electrical conductivity of poly(hydroxybutyrate-co-hydroxyvalerate)/ graphene biocomposites produced via different solvent
    ( 2021-05-03) ; ;
    Koh J.H.
    ;
    Jalil J.A.
    Poly(hydroxybutyrate-co-hydroxyvalerate) (PHBV) is among the most promising polymers used in a variety of applications, owing to its low cost, biodegradability, and nontoxicity. However, PHBV is electrically insulating; hence, limits its use in biomedical applications. This study demonstrates a straightforward and environment-friendly method to fabricate and modify the electrical conductivity of PHBV-based biocomposites by incorporating graphene (G) as conductive filler. PHBV/G bicomposite films were fabricated using acetic acid as an alternative to conventional solvents such as chloroform. The electrical conductivity of the biocomposite films with various loadings of graphene (0- 5 wt.%) was investigated by a two-point probe. It was discovered that, PHBV/G biocomposites at 5 wt.% graphene loading possess the highest electrical conductivity irrespective of the type of solvents used. Meanwhile, acetic acid casted PHBV/G biocomposite films have a greater electrical conductivity compared to chloroform casted PHBV/G biocomposite films.
  • Publication
    Green synthesis and characterization of Graphene quantum dots from key lime juice
    (Springer, 2023)
    Nur Atirah Afifah Sezali
    ;
    Siew Suan Ng
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    Al Rey Villagracia
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    ;
    Ruey-An Doong
    Graphene quantum dots (GQDs) are one of the members of graphene family with unique properties such as quantum confinement effect, photoluminescence effect, and strong conductivity. This work prepared the GQDs using lime juice obtained from the waste of locally grown key limes as the precursor. The hydrothermal method was used in the preparation of the GQDs. The fluorescence effect of the GQDs was observed under a UV lamp irradiation while other characterization was conducted using high-resolution transmission electron microscopy (HRTEM), atomic force microscopy (AFM), X-ray powder diffraction (XRD), and Raman spectroscopy. The GQD preparation was successful with the emission of a strong blue color when the GQD was put under a 365 nm UV light irradiation. It was found that the particle size of the prepared GQDs was in the range of 0.7–2.8 nm with an average diameter of 1.3 ± 0.5 nm. The characterization results proved the formation of GQDs as one of the graphene nanomaterials.
  • Publication
    Physicochemical Properties of Industrial Wood Waste-Derived Cellulose Nanofibrils
    ( 2024-01-01)
    Hing M.H.
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    ;
    Sezali N.A.A.
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    Ong H.L.
    ;
    Doong R.A.
    Wood is an important raw material, especially for construction and industrial scale activities which have resulted in a large amount of wood waste (WW). The accumulation of industrial WW has led to serious environmental issues; hence, the utilization of the industrial WW is being studied by researchers due to the rich content of cellulose. This study investigated the physicochemical properties of cellulose nanofibrils (CNFs) derived from industrial WW. The preparation of the CNFs involves the pretreatment of WW with an alkaline deep eutectic solvent (DES) and bleaching with peracetic acid, followed by 2,2,6,6-tetramethylpiperidine-1-oxyl (TEMPO)-mediated oxidation and mechanical post-treatment. Interestingly, the yield of the CNFs produced was 52%, which is half of the raw material used. Furthermore, the morphology of the WW-derived CNFs was analyzed from scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The WW-derived CNFs showed a uniform size with a width of around 20–100 nm and a length of several micrometers. Moreover, the production of WW-derived CNFs was further verified by Fourier transform infrared spectroscopy (FTIR) for the surface functional groups, X-ray diffraction (XRD) for the crystallography, and thermal gravimetry analysis (TGA) for thermal stability. The results obtained from these characterization methods have proved the successful transformation of the industrial WW into a high-potential nanomaterial, which is the CNFs that can be used for further applications in paper making, composites, packaging, textiles, biomedicine, energy storage, and electronics.
      5  18
  • Publication
    Effect of Different Filler Loading on Flexural Properties and Water Absorption Behavior of Kenaf Core Fiber Reinforced Polypropylene Composite
    ( 2020-11-24)
    Mustapa N.R.
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    ;
    In this investigation, kenaf core fiber (KCF) reinforced polypropylene (PP) composite was prepared via extrusion and compression moulding. The effect of different ratio of KCF filler with PP on flexural properties of composite had been investigated. PP and KCF filler were prepared with different filler loading of 5, 10, 15, 20 and 25 wt% using twin-screw extruder at temperature 180 °C and rotor speed of 70 rpm, followed by compression moulding at the same temperature. The flexural tests were conducted to evaluate the flexural properties of the composite. The results obtained showed that the incorporation of KCF in PP increased the flexural strength and flexural modulus of the composite. The water absorption behaviour of the composite was also investigated. It was found that water absorption of composites increased with increasing of fiber content.
      10  21
  • Publication
    The potential of chitosan-polygonum minus leaf mediated silver-nanoparticles composite as green conductive biofilm
    ( 2024-12) ; ; ;
    Muhammad Nabil Fikri Abd Nasir
    ;
    ;
    Zhi-Fu Lin
    Silver-nanoparticles (AgNPs) from leaf extract have gained considerable interest from years ago until recently. However, the potential of green-synthesised AgNPs as a conductive filler in polymer biocomposites has not been widely investigated. Herein, a series of biopolymer-silver nanoparticle films were prepared by dispersing the suspension of Polygonum minus leaf mediated AgNPs into chitosan (CS) matrix via solution casting. In this work, the physicochemical properties of the composite films were evaluated, and structural property was analysed by Fourier transform infrared (FTIR) spectroscopy. The electrical conductivity and surface morphology were investigated by two-point probe and scanning electron microscopy (SEM), respectively. From the evaluation of moisture uptake, solubility and degradation tests, the rate of moisture uptake reduced as AgNPs concentration increased whereas the solubility and degradation rate increased with increasing addition of AgNPs. The FTIR analysis confirmed that there was no new covalent bond formed and suggested that AgNPs interact non-covalently with amine and hydroxyl groups of chitosan matrix. The conductivity of the CS-AgNPs films increased with one-order magnitude from 10-8 to 10-7 S/cm compared to pristine CS film. The percolation threshold was achieved at 20 wt% of AgNPs and the highest conductivity was achieved at 30 wt% AgNPs with the conductivity value of 3.20 x 10-7 S/cm. SEM micrographs revealed that the composite film with 30 wt% AgNPs exhibited smooth and homogeneous surface which agrees well with the conductivity results. This CS-Polygonum minus leaf mediated AgNPs composite film shows potential as an alternative for biodegradable biomedical implants, smart packaging and wearable electronics applications.
      46  9
  • Publication
    Effect of graphene nanoplatelet addition on the electrical conductivity of poly(hydroxybutyrateco-hydroxyvalerate) biocomposites
    ( 2021-11-12) ;
    Ganesan O.
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    ;
    Rabat N.E.
    Poly(hydroxybutyrate-co-hydroxyvalerate) (PHBV) is one of the most promising biodegradable polymers used in many applications due to its biodegradability and non-toxicity. However, the usage of PHBV in electronic, biomedical, and biosensor applications has been limited due to its poor electrical properties. This study shows a simple method of producing and enhancing the electrical conductivity of PHBV-based biocomposites by adding graphene nanoplatelet (GNP) as a conductive filler. The biocomposite films were prepared using the solvent casting method, consist of five GNP loading (0-5 wt. %). The prepared PHBV/GNP biocomposites show enhanced electrical conductivity compared to neat PHBV. PHBV/GNP biocomposite with 5 wt. % filler loading exhibits the highest electrical conductivity at 3.83 × 10-3 S/cm. Higher crystalline regions in the PHBV/GNP biocomposites have facilitated the transfer of electrons between PHBV, resulting in the formation of conductive biocomposites, as evident from X-ray diffraction (XRD) characterization.
      3  19
  • Publication
    The effects of filler loading and coupling agents on properties of recycled high density Polyethylene/wood fiber composites
    The recycled high density polyethylene (rHDPE)/wood fiber (WF) composites had been prepared using Brabender Plasticorder at temperature 160ËšC with rotor speed of 50 rpm. The effect of wood fiber loading and coupling agents on tensile properties, water absorption, morphology, spectroscopy infrared (FTIR) analysis, thermogravimetric analysis (TGA) and x-ray diffraction (XRD) of rHDPE/WF composites were investigated. The results show that the addition of wood fiber reduced the tensile strength, elongation at break and interparticle spacing (d), whereas the modulus of elasticity, equilibrium water absorption percentage, thermal stability, and the crystal orientation ratio of composites increased. The coupling agents such as salicylic acid, maleic anhydride, and phthalic anhydride were used, which resulted in positive effect on tensile properties, water absorption, thermal stability and percentages of crystallinity of rHDPE/WF composites. Whereas the presence of coupling agents had increased the tensile strength, modulus of elasticity, thermal stability and crystal orientation ratio but decreased the elongation at break, water absorption and interparticle spacing (d). The results of various coupling agents on properties of rHDPE/WF30 composites have been examined. The study was showed that rHDPE/WFm/MAH composites showed higher tensile strength, modulus of elasticity, thermal stability and crystal orientation ratio followed by rHDPE/WFm/PAH composites > rHDPE/WFm (wood fiber treated salicylic acid) composites > rHDPE/WF composites in orders. Furthermore, lower the elongation at break, lower percentage equilibrium water absorption and lower interparticle spacing (d). The scanning electron microscopy (SEM) micrographs of tensile fracture surfaces for the composites with coupling agents of salicylic acid, maleic anhydride, and phthalic anhydride indicated that the interfacial interaction and adhesion between WF and rHDPE phases were better than rHDPE/WF composites.
      1  12
  • Publication
    The zinc ferrite decorated unexfoliated graphitic carbon nitride for effective antibiotic degradation under visible light
    (Trans Tech Publications Ltd., 2025)
    Muchammad Tamyiz
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    ;
    Atik Widiyanti
    The antibiotic pollutant treatment in wastewater using conventional method remains a challenge. One of the most fluoroquinolone antibiotics family used by human and animal cure is ciprofloxacin (CIP). CIP has exhibited as a recalcitrant compound in nature with concentration from ng to mg. To overcome this issue, recent technologies have applied such as photocatalysis technology for water decontamination. Furthermore, photocatalyst materials that used in this research were zinc ferrite and graphitic carbon nitride. A simple hydrothermal-coprecipitation method has succeed to synthesis zinc ferrite. While, unexfoliated graphitic carbon nitride (ZFO@ue-CN) was synthesized by calcination at 550 °C for 4 h under air condition. A heterostructure approach combining zinc ferrite and unexfoliated graphitic carbon nitride (ZFO@ue-CN) has been investigated as a potential solution. In this study, a ZFO@ue-CN was constructed by calcination method under atmosphere condition at 400 °C for 2 h. The ZFO@ue-CN has been characterized involving structural, morphological, and optical. Furthermore, ZFO@ue-CN exhibited excellent degradation performance with over 88% removal of ciprofloxacin. The heterojunction formation of ZFO@ue-CN nanocomposite provide more efficient electron transfer compared to single material. Combination between metal oxide@ue-CN can open up the new platform for simple material preparation, nevertheless it can keep the photodegradation performance. This result also emphasizes that the ZFO@ue-CN nanocomposites has prominent application for wastewater treatment.
      2  1
  • Publication
    Influence of filler loading and in situ salicylic acid treatment on corn husk fiber filled poly(Hydroxybutyrate-co-valerate)
    The effect of filler loading and in situ salicylic acid treatment on the mechanical properties and morphology of poly(hydroxybutyrate-co-valerate)/ corn husk fiber (PHBV/CHF) biocomposites was studied. Both untreated and salicylic acid treated PHBV/CHF biocomposites were prepared by using heated two roll mill followed by compression moulding. It was found that the addition of CHF to PHBV biocomposites increased the tensile strength and Young's modulus while the elongation at break decreased. Salicylic acid treated PHBV/CHF biocomposite display superior tensile strength and Young's modulus than untreated PHBV/CHF biocomposite due to the enhanced filler-matrix interaction. The better interfacial adhesion between CHF and PHBV matrix was confirmed through scanning electron microscope (SEM) analysis.
      1  20
  • Publication
    A review on mechanical properties of hybrid reinforced polymer composite
    ( 2020-11-02)
    Nur Rusyidah Mustapa
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    ;
    Development of hybrid fiber reinforced composite as sustainable alternatives material for some industrial and engineering applications have gained significant interests over past few years. The combination of two different types of reinforcing elements in a single matrix system produce a hybrid composite with special features such as biodegradability, low cost, low specific weight, and in some cases, enhance the mechanical, thermal and water absorption properties compared to single-fiber reinforced composite. In this paper, the mechanical properties (tensile properties, flexural properties and impact strength), thermal expansion and water absorption behavior of hybrid fiber-reinforced composite were reviewed and reported.
      10  21