Now showing 1 - 10 of 27
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The role of zinc chloride in enhancing mechanical, thermal and electrical performance of ethylene vinyl acetate/carbonized wood fiber conductive composite

2021-02-02 , Mohd Hanif Mohd Pisal , Azlin Fazlina Osman , Tan Soo Jin , Rozyanty Rahman , Alrashdi A.A. , Masa A.

Carbonized natural filler can offer the production of low cost composites with an eco-friendliness value. The evolving field of electronics encourages the exploration of more functions and potential for carbonized natural filler, such as by modifying its surface chemistry. In this work, we have performed surface modification on carbonized wood fiber (CWF) prior to it being used as filler in the ethylene vinyl acetate (EVA) composite system. Zinc chloride (ZnCl2) with various contents (2 to 8 wt%) was used to surface modify the CWF and the effects of ZnCl2 composition on the surface morphology and chemistry of the CWF filler were investigated. Furthermore, the absorptive, mechanical, thermal, and electrical properties of the EVA composites containing CWF-ZnCl2 were also analyzed. SEM images indicated changes in the morphology of the CWF while FTIR analysis proved the presence of ZnCl2 functional groups in the CWF. EVA composites incorporating the CWF-ZnCl2 showed superior mechanical, thermal and electrical properties compared to the ones containing the CWF. The optimum content of ZnCl2 was found to be 6 wt%. Surface modification raised the electrical conductivity of the EVA/CWF composite through the development of conductive deposits in the porous structure of the CWF as a channel for ionic and electronic transfer between the CWF and EVA matrix.

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Poly(ethylene-co-vinylacetate) copolymer based nanocomposites: a review

2020 , Azlin Fazlina Osman , Asna Rasyidah Abdul Hamid , Tuty Fareyhynn Mohammed Fitri , Asfa Amalia Ahmad Fauzi , Khairul Anwar Abdul Halim

Nowadays, there is huge demand for novel materials which are desired for new functions and new technological advancements. All technological demands for new applications cannot be implemented by many of the well-established materials, such as single plastics, metals or ceramics. Hence, engineers and scientists realized that, in comparison with pristine counterparts of material, the mixtures of materials can produce much better properties. Polymer nanocomposites is a new form of materials that resulted by the combination of polymers and nanofillers which contributed to various benefits over the neat polymer such as improvement in biocompatibility, biostability, thermal stability, flame retardancy, mechanical and barrier properties. Due to these factors, nanocomposites have received an extraordinary consideration for use in broad range of applications. However, the polymer nanocomposites which comprised of copolymer as matrix material are not widely studied, especially those involved poly(ethylene-co-vinyl acetate) (PEVA). The production of PEVA copolymer-based nanocomposites for various applications has been reported by few research papers. In this communication, a review on the properties of PEVA-based nanocomposites with different types of nanofiller was summarized, revealing the high potential of this class of nanocomposite for advanced applications.

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Methyl Methacrylate (MMA) treatment of Empty Fruit Bunch (EFB) to improve the properties of regenerated cellulose biocomposite films

2020 , Salmah Husseinsyah , Nur Liyana Izyan Zailuddin , Azlin Fazlina Osman , Chew Li Li , Awad A. Alrashdi , Abdulkader Alakrach

The empty fruit bunch (EFB) regenerated cellulose (RC) biocomposite films for packaging application were prepared using ionic liquid. The effects of EFB content and methyl methacrylate (MMA) treatment of the EFB on the mechanical and thermal properties of the RC biocomposite were studied. The tensile strength and modulus of elasticity of the MMA treated RC biocomposite film achieved a maximum value when 2 wt% EFB was used for the regeneration process. The treated EFB RC biocomposite films also possess higher crystallinity index. The morphology analysis indicated that the RC biocomposite film containing MMA treated EFB exhibits a smoother and more homogeneous surface compared to the one containing the untreated EFB. The substitution of the –OH group of the EFB cellulose with the ester group of the MMA resulted in greater dissolution of the EFB in the ionic liquid solvent, thus improving the interphase bonding between the filler and matrix phase of the EF RC biocomposite. Due to this factor, thermal stability of the EFB RC biocomposite also successfully improved.

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The use of ground & ultrasonicated dolomite (GUD) for improving the tensile performance of Poly (ethylene-co-vinyl acetate) copolymer composite

2021-11-12 , Fauzi A.A.A. , Azlin Fazlina Osman , Khairul Anwar Abdul Halim , Mustafa Z. , Alakrach A.M. , Mohd Nazry Salleh

The combination of the organic and inorganic materials to fabricate a new form of material called 'composite' has been performed since several decades ago. However, the strategy to improve the homogeneity of the resultant composite system is still being the main focus of current research. In this study, dolomite and poly (ethylene-co-vinyl acetate) (PEVAc) were employed as filler and matrix, respectively. Dolomite was ground and ultrasonicated before being used as filler. It can be observed that the size of dolomite particles has been reduced significantly upon the grinding and ultrasonication processes. The effect of ground and ultrasonicated dolomite (GUD) addition on the mechanical performance of the PEVAc copolymer was investigated. Results indicate that the GUD filler has successfully increased the tensile strength, elongation at break, modulus of elasticity and tensile toughness of the PEVAc copolymer when being employed in 1 wt%. However, the use of higher content of GUD resulted in the decreasing trend of those properties. This shows that the ground and ultrasonicated dolomite with smaller and higher surface area particles than its pristine form could bring improvement to the mechanical performance of the copolymer when being used in low loading as it can be more easily dispersed in the copolymer matrix.

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Incorporation of hybrid pre-dispersed organo-montmorillonite/destabilized bentonite nanofillers for improving tensile strength of PEVA copolymer with 40% vinyl acetate composition

2020 , Tuty Fareyhynn Mohammed Fitri , Azlin Fazlina Osman , Rahimah Othman , Zaleha Mustafa

In this work, soft and flexible poly (ethylene-co-vinyl acetate) (PEVA) with 40% vinyl acetate (VA) composition was used as matrix material to form nanocomposites with single nanofiller (organo-montmorillonite (OMMT) or Bentonite (Bent)) and hybrid nanofillers (OMMT+Bent in the ratios of 4:1, 3:2, 2:3 and 1:4). In order to achieve greater exfoliation and dispersion of the hybrid nanofillers in the PEVA matrix, the pre- dispersing and destabilization technique was applied to the O-MMT and Bent, respectively. The procedures were done prior to the melt compounding process of the nanocomposite. A tensile test was done to evaluate the mechanical properties of the resultant nanocomposites and to allow the selection of the best OMMT/Bent ratio for the production of the hybrid nanocomposite. The structure and fractured surfaces of the neat PEVA and nanocomposite were analyzed using Fourier Transform Infrared (FTIR) and Scanning Electron Microscopy (SEM), respectively. Results indicated that the addition of hybrid pre-dispersed OMMT/destabilized bentonite nanofillers into the PEVA matrix resulted in greater mechanical performance as compared to the single OMMT or single Bent nanofiller. The best achievement in the tensile strength and elongation at break of the PEVA hybrid nanocomposite was obtained when the hybrid nanofillers was added in the ratio of 4:1 (OMMT: Bent). The SEM analysis showed that the PEVA hybrid nanocomposite with 4OMMT: 1Bent had greater matrix deformation than the neat PEVA when subjected to tensile load. This mechanical deformation could be related to the increased flexibility of the PEVA chains which facilitated more energy absorption during the stretching of the material. Apparently, this mechanism acted as a matrix toughening process which allowed the increment of both tensile strength and elongation at break values of the PEVA upon the addition of the hybrid nanofillers.

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Physical, thermal transport, and compressive properties of epoxy composite filled with graphitic- and ceramic-based thermally conductive nanofillers

2022 , Siti Salmi Samsudin , Mohd Shukry Abdul Majid , Mohd Ridzuan Mohd Jamir , Azlin Fazlina Osman , Mariatti Jaafar , Hassan A. Alshahrani

Epoxy polymer composites embedded with thermally conductive nanofillers play an important role in the thermal management of polymer microelectronic packages, since they can provide thermal conduction properties with electrically insulating properties. An epoxy composite system filled with graphitic-based fillers; multi-walled carbon nanotubes (MWCNTs), graphene nanoplatelets (GNPs) and ceramic-based filler; silicon carbide nanoparticles (SiCs) was investigated as a form of thermal-effective reinforcement for epoxy matrices. The epoxy composites were fabricated using a simple fabrication method, which included ultrasonication and planetary centrifugal mixing. The effect of graphite-based and ceramic-based fillers on the thermal conductivity was measured by the transient plane source method, while the glass transition temperature of the fully cured samples was studied by differential scanning calorimetry. Thermal gravimetric analysis was adopted to study the thermal stability of the samples, and the compressive properties of different filler loadings (1–5 vol.%) were also discussed. The glass temperatures and thermal stabilities of the epoxy system were increased when incorporated with the graphite- and ceramic-based fillers. These results can be correlated with the thermal conductivity of the samples, which was found to increase with the increase in the filler loadings, except for the epoxy/SiCs composites. The thermal conductivity of the composites increased to 0.4 W/mK with 5 vol.% of MWCNTs, which is a 100% improvement over pure epoxy. The GNPs, SiCs, and MWCNTs showed uniform dispersion in the epoxy matrix and well-established thermally conductive pathways.

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Thermoplastic starch hybrid biocomposite films with improved strength and flexibility produced through crosslinking via carboxylic acid

2023 , Di Sheng Lai , Azlin Fazlina Osman , Sinar Arzuria Adnan , Ismail Ibrahim , Midhat Nabil Ahmad Salimi , Mariatti Jaafar @ Mustapha

Thermoplastic starch (TPS) suffers from its intrinsic low mechanical strength and high brittleness due to its strong hydrogen bonding and low chain mobility. The conventional way to crosslink the TPS film can improve the strength and stiffness of the films, but usually reduces the flexibility of the film, and increases its brittleness. In this study, the incorporation of the hybrid nanofiller [1 wt% nanocellulose (C) and 4 wt% nano bentonite (B)] into the TPS proved to improve greatly the films’ strength and flexibility. The hybrid nanofillers with ratio 4B:1C was incorporated into the crosslinked thermoplastic corn starch (CR-TPCS) film to increase the its flexibility and toughness and produced a high mechanical strength fully biodegradable film. Two different aqueous carboxylic acids: citric acid (CA) and tartaric acid (TA) with different pH values (2,4,6) as the green crosslinker were employed. Substantial increase of tensile strength (3.98 to 9.17 MPa), Young’s modulus (9.10 to 46.30 MPa) and elongation at break (55.2 to 135.7%) was observed for the CA- 4B1C/pH2 films compared to the CR-TPCS films. The melting temperature (Tm) of the CA-4B1C/pH2 improved compared to the TPCS/4B1C (un-crosslinked) film due to its crosslinking effect. Meanwhile, the CA-4B1C films exhibited the highest degree of substitution and di-esterification with the lowest swelling and water solubility properties due to the formation of a special “bridge” structure between the CA, nanocellulose and plasticizer. The “bridge” structure developed between the TPCS chains serves as the toughener to motivate higher chain stress relaxation and load endurance. The crosslinked “bridge structure” also proved to effectively reduce the retrogradation phenomenal in the TPCS films. This combination method of hybridization and crosslinking is an efficient, low cost, and environmentally friendly technique to overcome the low flexibility and brittleness problem of the TPS based packaging film.

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The Influence of Compounding Parameters on the Electrical Conductivity of LDPE/Cu Conductive Polymer Composites (CPCs)

2021-11-12 , Farah Badrul , Khairul Anwar Abdul Halim , Mohd Arif Anuar Mohd Salleh , Azlin Fazlina Osman , Nor Asiah Muhamad , Muhammad Salihin Zakaria , Nurul Afiqah Saad , Syatirah Mohd Noor

Low-linear density (LDPE) and copper (Cu) were used as main polymer matrix and conductive filler in order to produce electrically conductive polymer composites (CPC). The selection of the matrix and conductive filler were based on their due to its excellence properties, resistance to corrosion, low cost and electrically conductive. This research works is aimed to establish the effect of compounding parameter on the electrical conductivity of LDPE/Cu composites utilising the design of experiments (DOE). The CPCs was compounded using an internal mixer where all formulations were designed by statistical software. The scanning electron micrograph (SEM) revealed that the Cu conductive filler had a flake-like shape, and the electrical conductivity was found to be increased with increasing filler loading as measured using the four-point probe technique. The conductivity data obtained were then analysed by using the statistical software to establish the relationship between the compounding parameters and electrical conductivity where it was found based that the compounding parameters have had an effect on the conductivity of the CPC.

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Toughening mechanism of thermoplastic starch nano-biocomposite with the hybrid of nanocellulose/nanobentonite

2023 , Lai Di Sheng , Azlin Fazlina Osman , Sinar Arzuria Adnan , Mariatti Jaafar@Mustapha , Ismail Ibrahim , Midhat Nabil Ahmad Salimi

High flexibility and toughness are key criteria for an effective bioplastic packaging film. However, in most studies, the flexibility of thermoplastic starch (TPS) films is always neglected when targeting their tensile strength improvement. Low film flexibility has limited the development of TPS films in replacing the petrochemical-based plastic packaging films. In this communication, we report a method to produce thermoplastic corn starch (TPCS) films with excellent mechanical strength, high flexibility and high toughness through the hybridization of two natural nanofillers: nanobentonite and nanocellulose. The synergistic effect of the hybrid nanofillers can be observed through the arrangement of alternating nacre structures where the nanobentonite silicate layers are responsible for mechanical strength, while the nanocellulose promotes free volume in the TPCS matrix and triggers high film elongation at break. Structural, morphological, and thermomechanical analysis were conducted, and the detailed strengthening mechanism of the TPCS hybrid nano-biocomposite films was revealed.

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Impact of Mendong fiber–epoxy composite interface properties on electric field frequency exposure

2023-11-01 , Suryanto H. , Irawan Y.S. , Soenoko R. , Binoj J.S. , Azlin Fazlina Osman , Hakimah Osman , Maulana J. , Ali A.

This research investigates the effects of the frequency of the external electric field during the curing process on the interfacial properties of epoxy composites reinforced by Mendong fiber. Epoxy was used as a matrix with cycloaliphatic amine as a curing agent. The AC electric field by frequencies of 1, 2, and 3 kHz and strength of 750 V/cm were applied during the curing process. The functional groups, structure, interface properties, and morphology of treated epoxy were observed using Fourier-transform infrared, x-ray diffraction, scanning electron microscope, and pull-out test, respectively. The result indicates that after treatment with an electric field of 1 kHz, new peaks were observed in the epoxy diffractogram at the angle of 6.2° and 12.3°, change in morphology, the wettability properties of epoxy were increased and interface shear strength was improved. Increasing the frequency of electric fields results in more damage to the interface and subsequently reduces the shear strength at the interface. Highlights: Interface properties of the composite after curing in an electric field characterized. Exposure to electric field frequency during curing changed epoxy properties. Shear strength of Mendong fiber/epoxy varied post-exposure to the electric field.