Displaying publications 21 - 40 of 72 in total

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  1. Mechanical, morphological and structural properties of cellulose nanofibers reinforced epoxy composites
    Saba N, Mohammad F, Pervaiz M, Jawaid M, Alothman OY, Sain M
    Int J Biol Macromol, 2017 Apr;97:190-200.
    PMID: 28082223 DOI: 10.1016/j.ijbiomac.2017.01.029
    Present study, deals about isolation and characterization of cellulose nanofibers (CNFs) from the Northern Bleached Softwood Kraft (NBSK) pulp, fabrication by hand lay-up technique and characterization of fabricated epoxy nanocomposites at different filler loadings (0.5%, 0.75%, 1% by wt.). The effect of CNFs loading on mechanical (tensile, impact and flexural), morphological (scanning electron microscope and transmission electron microscope) and structural (XRD and FTIR) properties of epoxy composites were investigated. FTIR analysis confirms the introduction of CNFs into the epoxy matrix while no considerable change in the crystallinity and diffraction peaks of epoxy composites were observed by the XRD patterns. Additions of CNFs considerably enhance the mechanical properties of epoxy composites but a remarkable improvement is observed for 0.75% CNFs as compared to the rest epoxy nanocomposites. In addition, the electron micrographs revealed the perfect distribution and dispersion of CNFs in the epoxy matrix for the 0.75% CNFs/epoxy nanocomposites, while the existence of voids and agglomerations were observed beyond 0.75% CNFs filler loadings. Overall results analysis clearly revealed that the 0.75% CNFs filler loading is best and effective with respect to rest to enhance the mechanical and structural properties of the epoxy composites.
    Matched MeSH terms: Epoxy Resins/chemistry*
  2. Epoxidation and hydroxylation of liquid natural rubber
    Nur Hanis Adila Azhar, Nur Hanis Adila Azhar Hamizah Md Rasid, Siti Fairus M. Yusoff
    Sains Malaysiana, 2017;46:485-491.
    Liquid natural rubber (LNR) was functionalized into liquid epoxidized natural rubber (LENR) and hydroxylated LNR (LNROH)
    via oxidation using a Na2
    WO4
    /CH3
    COOH/H2
    O2
    catalytic system. Microstructures of LNR and functionalized LNRs
    were characterized using Fourier Transform Infrared (FTIR) and Nuclear Magnetic Resonance (NMR) spectroscopies. The
    effect of CH3
    COOH, H2
    O2
    , Na2
    WO4
    , reaction time and temperature. reaction time and temperature on epoxy content were
    investigated. LNR-OH was obtained when oxidation reaction was conducted at a longer reaction time, higher temperature
    or excess amount of catalyst. Thermogravimetric analysis (TGA) reported the thermal behavior of functionalized LNRs.
    Molecular weight and polydispersity index (PDI) were determined using gel permeation chromatography (GPC).
    Matched MeSH terms: Epoxy Resins
  3. Rapid extraction of bisphenol a by dispersive liquid-liquid microextraction based on solidification of floating organic
    Shan TO, Mee LN, Marinah Mohd Ariffin, Saw HL
    Sains Malaysiana, 2017;46:615-621.
    Bisphenol A is an endocrine disruptor with widespread applications, especially in the production of polycarbonate and epoxy resins. Dispersive liquid-liquid microextraction based on solidification of floating organic technique has been developed for the extraction of bisphenol A from water and soft drink. The 1-undecanol has been applied as the extraction solvent because of its low density and melting point and high affinity to the analyte. The technique offered rapid and simple analysis as the 1-undecanol was homogeneously dispersed in the sample solution to speed the extraction and the collection of extraction solvent was simplified by centrifugation, cooling and melting steps.
    Matched MeSH terms: Epoxy Resins
  4. Fulltext Effect of acid and Silane treated Carbon nanotubes on wear properties of Epoxy polymer composite
    Aidah Jumahat, Napisah Sapiai, Eliya Farah Hana Mohd Kamal
    Pertanika Journal of Science & Technology, 2017;25(103):213-222.
    MyJurnal
    This paper investigates the effect of acid and silane treatment of Carbon Nanotubes (CNT) on wear properties of epoxy polymer composite. The wear test done was based on ASTM D3389 standard using the Abrasive Wear Tester (TR 600). Characterisation analysis was also done using Transmission Electron Microscopy (TEM) in order to study the dispersion of the CNT inside the epoxy matrix. When untreated CNT was added to the epoxy with amounts of 0.5, 0.75 and 1.0 wt%, the wear rates did not improve except for 0.5 wt% CNT filled epoxy. This was due to the lack of dispersion which causes larger chunks of material being dug out, thus contributing to a higher mass loss and wear rate. When treated with acid and silane, 0.75 wt% and 1.0 wt% CNT filled epoxy composites showed improvement. The TEM images of 0.5 wt%, 0.75 wt% and 1.0 wt% PCNT filled epoxy supported the claim of the lack of dispersion of PCNT inside the epoxy.
    Matched MeSH terms: Epoxy Resins
  5. Fulltext Tensile and compressive properties of unidirectional Arenga Pinnata fibre reinforced epoxy composite
    Aidah Jumahat, Muhamad Faris Syafiq Khalid, Zuraidah Salleh, Mohammad Jawaid
    Pertanika Journal of Science & Technology, 2017;25(107):299-308.
    MyJurnal
    This paper presents a study on the effect of Arenga Pinnata fibre volume fraction on the tensile and compressive properties of Arenga Pinnata fibre reinforced epoxy composite (APREC). The composites were produced using four different Arenga Pinnata fibre volume contents, which were 10vol%, 15vol%, 20vol%, and 25vol%, in unidirectional (UD) fibre alignment. Tensile and compression tests were performed on all APREC specimens in order to investigate the effect of fibre volume fraction on modulus of elasticity, strength and strain to failure. The morphological structure of fractured specimens was observed using scanning electron microscopy (SEM) in order to evaluate the fracture mechanisms involved when the specimens were subjected to tensile or compressive loading. The results indicated that the higher the amount of Arenga Pinnata fibres, the higher the stiffness of the composites. This is shown by the increment of tensile and compressive modulus of the specimens when the fibre volume content was increased. Tensile modulus increased up to 180% when 25vol% Arenga Pinnata fibre was used in APREC compared to Pure Epoxy specimen. It can also be observed that the tensile strength of the specimens increased 28% from 53.820 MPa (for Pure Epoxy) to 68.692 MPa (for Epoxy with 25vol% APREC addition). Meanwhile, compressive modulus and strength increased up to 3.24% and 9.17%, respectively. These results suggest that the addition of Arenga Pinnata fibres significantly improved the tensile and compressive properties of APREC.
    Matched MeSH terms: Epoxy Resins
  6. Fulltext Hole size effects on the open hole tensile properties of Woven Kevlar-Glass Fibre hybrid composite laminates
    Norazean Shaari, Aidah Jumahat
    Pertanika Journal of Science & Technology, 2017;25(107):309-318.
    MyJurnal
    The effects of hole size on open hole tensile properties of Kevlar-glass fibre hybrid composite laminates were thoroughly investigated in this work. Woven Kevlar/glass fibre epoxy composite laminates were fabricated using hand lay-up and vacuum bagging technique. Specimens of five different hole size (1 mm, 4 mm, 6 mm, 8 mm and 12 mm) were carefully prepared before the tensile test was performed according to ASTM D5766. Results indicated that hybridizing Kevlar to glass fibres improved tensile strength and failure strain of hybrid composite specimen. In addition, increasing the hole size reduced strength retention of the hybrid specimen from 96% for 1 mm hole size to 62% and 44% for 6 mm and 12 mm, respectively. Fractography analysis showed that several types of failure mechanisms were observed such as brittle failure, ductile failure, fibre breakage, delamination and fibre-matrix splitting. It is concluded that as hole size increased, failure behaviour changed from a matrix dominated failure mode to a fibre-dominated failure mode.
    Matched MeSH terms: Epoxy Resins
  7. Fulltext Effect of Silica Nanoparticles in Kenaf Reinforced Epoxy: Flexural and compressive properties
    Bajuri, F., Mazlan, N., Ishak, M.R.
    Pertanika Journal of Science & Technology, 2017;25(3):1029-1038.
    MyJurnal
    Kenaf natural fibre is used as a sustainable form of material to reinforce polymeric composite. However, natural fibres usually do not perform as well as synthetic fibres. Silica nanoparticle is a material with high surface area and its high interfacial interaction with the matrix results in its improvement. In this research, silica nanoparticles were introduced into epoxy resin as a filler material to improve the mechanical properties of the kenaf-reinforced epoxy. They were dispersed into the epoxy using a homogeniser at 3000 rpm for 10 minutes. The composites were fabricated by spreading the silica filled epoxy evenly onto the kenaf mat before hot pressing the resin wet kenaf mat. The results show for flexural properties, composites with higher fibre and silica volume content generally had better properties with specimen 601 (60 vol% kenaf and1 vol% silica) having the highest strength at 68.9 MPa. Compressive properties were erratic with specimen 201 (20 vol% kenaf and 1 vol% silica) having the highest strength at 53.6 MPa.
    Matched MeSH terms: Epoxy Resins
  8. Fulltext An in vitro Comparison of Bond Strength of Different Sealers/Obturation Systems to Root Dentin Using the Push-Out Test at 2 Weeks and 3 Months after Obturation
    Yap WY, Che Ab Aziz ZA, Azami NH, Al-Haddad AY, Khan AA
    Med Princ Pract, 2017;26(5):464-469.
    PMID: 28934753 DOI: 10.1159/000481623
    OBJECTIVE: To evaluate the push-out bond strength and failure modes of different sealers/obturation systems to intraradicular dentin at 2 weeks and 3 months after obturation compared to AH Plus®/gutta-percha.

    MATERIALS AND METHODS: A total of 180 root slices from 60 single-canal anterior teeth were prepared and assigned to 5 experimental groups (n = 36 in each group), designated as G1 (AH Plus®/gutta-percha), G2 (TotalFill BC™ sealer/BC-coated gutta-percha), G3 (TotalFill BC™ sealer/gutta-percha), G4 (EndoREZ® sealer/EndoREZ®-coated gutta-percha), and G5 (EndoREZ® sealer/gutta-percha). Push-out bond strengths of 18 root slices in each group were assessed at 2 weeks and the other 18 at 3 months after obturation using a universal testing machine. Data were analyzed using repeated measures ANOVA. An independent t test was used to compare the mean push-out bond strength for each group at 2 weeks and 3 months after obturation.

    RESULTS: The mean push-out bond strengths of G4 and G5 were significantly lower than those of G1, G2, and G3 (p < 0.05) at both 2 weeks (G1: 1.46 ± 0.29 MPa, G2: 1.74 ± 0.43 MPa, G3: 1.74 ± 0.43 MPa, G4: 0.66 ± 0.31 MPa, G5: 0.74 ± 0.47 MPa) and 3 months after obturation (G1: 1.70 ± 1.05 MPa, G2: 3.69 ± 1.20 MPa, G3: 2.84 ± 0.83 MPa, G4: 0.14 ± 0.05 MPa, G5: 0.24 ± 0.10 MPa). The mean push-out bond strengths of G2 (3.69 ± 1.20 MPa) and G3 (2.84 ± 0.83 MPa) were higher at 3 months compared to 2 weeks after obturation (G2: 1.74 ± 0.43 MPa, G3: 1.33 ± 0.29 MPa).

    CONCLUSION: The TotalFill BC™ obturation system (G2) and the TotalFill BC™ sealer/gutta-percha (G3) showed comparable bond strength to AH Plus®. Their bond strength increased over time, whereas the EndoREZ® obturation system (G4) and EndoREZ sealer (G5) had low push-out bond strength which decreased over time.

    Matched MeSH terms: Epoxy Resins/chemistry
  9. Fulltext Investigation on the flexural properties and glass transition temperature of kenaf/epoxy composite filled with mesoporous silica for wind turbine applications
    Chai Hua, T., Norkhairunnisa, M.
    Pertanika Journal of Science & Technology, 2017;25(4):1261-1274.
    MyJurnal
    This research investigates the strength of kenaf or epoxy composite filled with mesoporous silica and
    studies the hybrid effects between mesoporous silica or kenaf in epoxy matrix. The volume of kenaf
    woven mat is maintained constantly at 7.2vol%, whereas proportion of epoxy is varied with inclusion of
    mesoporous silica and silicon, keeping constant the volume of the composite at 67.5cm3. The proportion
    of mesoporous silica is altered from 0.5vol%, 1.0vol%, 3.0vol% and 5.0vol%, while silicon is kept
    constant at 3.0vol%. A total of 11 specimens were produced, each with its distinctive composition and
    mechanical strengths. Variation of fillers composition affects the mechanical strengths of the composite.
    SEM analysis shows that epoxy bonds well with silicon, kenaf and mesoporous silica. Some de-bonding
    among the components is observed within the composite although there is also some tearing of fibres and
    impregnation of epoxy within fibre, proving that the components have good interaction and do not act
    individually. Flexural test shows that mesoporous silica improves the flexural strength of the composite,
    where the highest value is 35.14MPa, obtained at 5.0vol% Mesoporous Silica in Kenaf/Epoxy (SiaK/
    Ep). It also improves the flexural modulus, where the highest value is 1569.48MPa, obtained at 3.0vol%
    SiaK/Ep. DMA result reveals that adding mesoporous silica increases the Tg of the composite produced.
    Highest Tg is obtained at 0.5vol% Mesoporous Silica in Kenaf/Epoxy modofied Silicon (SiaK/Ep-Si)
    with the value of 87.54°C.
    Matched MeSH terms: Epoxy Resins
  10. Fulltext Assessments of Secondary Reinforcement of Epoxy Matrix-Glass Fibre Composite Laminates through Nanosilica (SiO₂)
    Lazar PJL, Sengottuvelu R, Natarajan E
    Materials (Basel), 2018 Nov 05;11(11).
    PMID: 30400592 DOI: 10.3390/ma11112186
    The principal objective of this research work was to investigate the results of impregnating epoxy matrix-glass fibre composite laminates with nanosilica as secondary reinforcement. 0.5, 0.75, 1 and 3 wt% nanosilica was used and thereafter properties of composites were assessed through tensile, three point bending, quasi static indentation tests and dynamic mechanical analysis. Scanning electron microscope examinations were done on fracture surfaces and failure modes were analyzed. The internal failures of the composite due to quasi-static indentation were evaluated through C-Scan. Among samples of different weight fractions, 0.75 wt% nanosilica reinforced composite laminates exhibited substantial increase of 42% in tensile strength and 39.46% in flexural strength. The reduction in glass transition temperature (Tg), increase in storage modulus (E'), loss modulus (E″) and damping factor (tan δ) were also observed. Quasi-static indentation assessments revealed that energy absorption property was enhanced significantly by 53.97%. Hence nanosilica up to 0.75 wt% can be used as a potential candidate for secondary reinforcement in epoxy composite laminates.
    Matched MeSH terms: Epoxy Resins
  11. Fulltext Interfacial Compatibility Evaluation on the Fiber Treatment in the Typha Fiber Reinforced Epoxy Composites and Their Effect on the Chemical and Mechanical Properties
    Rizal S, Ikramullah, Gopakumar DA, Thalib S, Huzni S, Abdul Khalil HPS
    Polymers (Basel), 2018 Nov 28;10(12).
    PMID: 30961241 DOI: 10.3390/polym10121316
    Natural fiber composites have been widely used for various applications such as automotive components, aircraft components and sports equipment. Among the natural fibers Typha spp have gained considerable attention to replace synthetic fibers due to their unique nature. The untreated and alkali-treated fibers treated in different durations were dried under the sun for 4 h prior to the fabrication of Typha fiber reinforced epoxy composites. The chemical structure and crystallinity index of composites were examined via FT-IR and XRD respectively. The tensile, flexural and impact tests were conducted to investigate the effect of the alkali treated Typha fibers on the epoxy composite. From the microscopy analysis, it was observed that the fracture mechanism of the composite was due to the fiber and matrix debonding, fiber pull out from the matrix, and fiber damage. The tensile, flexural and impact strength of the Typha fiber reinforced epoxy composite were increased after 5% alkaline immersion compared to untreated Typha fiber composite. From these results, it can be concluded that the alkali treatment on Typha fiber could improve the interfacial compatibility between epoxy resin and Typha fiber, which resulted in the better mechanical properties and made the composite more hydrophobic. So far there is no comprehensive report about Typha fiber reinforcing epoxy composite, investigating the effect of the alkali treatment duration on the interfacial compatibility, and their effect on chemical and mechanical of Typha fiber reinforced composite, which plays a vital role to provide the overall mechanical performance to the composite.
    Matched MeSH terms: Epoxy Resins
  12. Fulltext The effects of alkali treatment on the mechanical and chemical properties of banana fibre and adhesion to Epoxy resin
    Zin, M.H., Abdan, K., Norizan, M.N., Mazlan, N.
    Pertanika Journal of Science & Technology, 2018;26(1):161-176.
    MyJurnal
    The main focus of this study was to obtain the optimum alkaline treatment for banana fibre and the its effect on the mechanical and chemical properties of banana fibre, its surface topography, its heat resistivity, as well as its interfacial bonding with epoxy matrix. Banana fibre was treated with sodium hydroxide (NaOH) under various treatment conditions. The treated fibres were characterised using FTIR spectroscopy. The morphology of a single fibre observed under a Digital Image Analyser indicated slight reduction in fibre diameter with increasing NaOH concentration. The Scanning Electron Microscope (SEM) results showed the deteriorating effect of alkali, which can be seen from the removal of impurities and increment in surface roughness. The mechanical analysis indicates that 6% NaOH treatment with a two-hour immersion time gave the highest tensile strength. The adhesion between single fibre and epoxy resin was analysed through the micro-droplet test. It was found that 6% NaOH treatment with a two-hour immersion yielded the highest interfacial shear stress of 3.96 MPa. The TGA analysis implies that alkaline treatment improved the thermal and heat resistivity of the fibre.
    Matched MeSH terms: Epoxy Resins
  13. Fulltext A preliminary study on paper sheets based Epoxy composites designed for repairing work application and its properties – a review
    Muhamad Hellmy Hussin
    Pertanika Journal of Science & Technology, 2018;26(3):923-932.
    MyJurnal
    This is a review of studies on various types of paper-based epoxy composites currently being designed and developed for technological use. The concept of designing composite materials is very significant for small to large industry and it is important where initiation of repairing work is now being considered for engineering applications. This composite material is of interest due to its advantages compared with others, including low environmental effects and low cost for a wide range of works. This review aims to provide an overview of morphological, physical and mechanical properties of various paper sheetsbased epoxy composites and details of achievements made. From this approach, this paper also presents the preliminary study of SEM results of paper sheets-based epoxy composites designed for repairing work applications. It has been found that a well-arranged laminated paper sheet layers could help the bond strength with epoxy matrix. Thus, this paper sheet-based epoxy composite can be considered as an easiest way, cheap and biodegradable that can be used for various small repairing works in structural and automotive applications.
    Matched MeSH terms: Epoxy Resins
  14. Fulltext Effect of ZnO-PEDOT:PSS incorporation in epoxy based coating on corrosion behaviour in immersed condition
    Nur Ain, A.R., Mohd Sabri, M.G., Wan Rafizah, W.A., Nurul Azimah, M.A., Wan Nik, W.B.
    ASM Science Journal, 2018;11(101):56-67.
    MyJurnal
    Corrosion is a natural deterioration process that destructs metal surface. Metal of highly
    protected by passivation layer such as Stainless Steel 316L also undergoes pitting corrosion
    when continuously exposed to aggressive environment. To overcome this phenomenon, application
    of epoxy based coating with addition of zinc oxide- poly (3,4-ethylenedioxythiophene)
    doped with poly (styrene sulphonate) hybrid nanocomposite additive was introduced as
    paint/metal surface coating. The compatibility between these two materials as additive
    was studied by Fourier Transform Infrared Spectroscopy (FTIR), X-ray Diffraction (XRD),
    Field Emission Scanning Electron Microscopy/Energy-Dispersive X-ray spectroscopy (FESEM/EDX)
    and Transmission Electron Microscopy (TEM) analysis. The effect of nanocomposite
    wt.% in epoxy based coating with immersion duration in real environment on corrosion
    protection performance was analyzed through potentiodynamic polarization analysis. The
    main finding showed that addition of hybrid nanocomposite had increased corrosion protection
    yet enhanced corrosion process when excess additives was loaded into epoxy coating.
    Addition of 2 wt.% ZnO-PEDOT:PSS was found significantly provided optimum corrosion
    protection to stainless steel 316L as the corrosion rate for 0 day, 15 days and 30 days of
    immersion duration is 0.0022 mm/yr, 0.0004 mm/yr and 0.0015 mm/yr; respectively.
    Matched MeSH terms: Epoxy Resins
  15. Fulltext Release of bisphenol a from polycarbonate and polyethylene terephthalate drinking water bottles under different storage conditions and its associated health risk
    Wen Min Yun, Yu Bin Ho, Eugenie Sin Sing Tan, Vivien How
    Malaysian Journal of Medicine and Health Sciences, 2018;14(102):1-9.
    MyJurnal
    Bisphenol A (BPA) is a controversial plastics ingredient used mainly in the production of polycarbonate plastics (PC) and epoxy resins that widely used nowadays in food and drink packaging. Even though BPA is not involved in polyethylene terephthalate (PET) manufacturing, recent study had reported the present of BPA in PET water bottle. This study was conducted to investigate effects storage conditions on release of BPA from PC and PET bottled water as well as to assess health risks associated with consumption. Methods: Solid phase extraction (SPE) was used to extract the samples, followed by analysis using ultra high performance liquid chromatography with fluorescence detector (UHPLC-FLD). The possibility of developing chronic non-carcinogenic health risk among consumers of bottled water was evaluated using hazard quotient (HQ). Results: Results showed that BPA migrated from PC and PET water bottles at concentrations ranging from 9.13 to 257.67 ng/L and 11.53 ng/L to 269.87 ng/L respectively. Concentrations of BPA were higher in PET bottled water compared to PC bottled water across all storage conditions. Higher storage temperature and longer storage duration increased BPA concentrations in PC and PET bottled water. Concentrations of BPA in bottled water which were kept in a car and were exposed to sunlight were higher than control samples which were stored indoor at room temperature. Conclusion: No significant chronic non-carcinogenic health risks were calculated for daily ingestion of BPA-contaminated bottled water; calculated HQ was less than one.
    Matched MeSH terms: Epoxy Resins
  16. Multi-walled carbon nanotubes/woven kenaf fabric-reinforced epoxy laminated composites
    Nurul Hidayah Ismail, Mohd Hafizi Mohamad, Mariatti Jaafar
    Sains Malaysiana, 2018;47:563-569.
    This study was carried out to investigate the effect of adding 1 vol% of multi-walled carbon nanotubes (MWCNT) into
    woven kenaf/epoxy laminated composites on their flexural properties and to compare between two techniques used to
    incorporate MWCNT into the composite which are spraying and solution techniques. Furthermore, the effect of MWCNT
    addition in woven glass/woven kenaf/epoxy hybrid composites at the same filler concentration on the flexural properties
    were also investigated. All the laminated composites with and without MWCNT were fabricated using vacuum bagging
    method. The flexural properties of the composite samples with and without MWCNT were evaluated by applying threepoint
    bending test. The results were supported by morphological observation. It was found that the addition of MWCNT
    using both spraying and solution techniques reduced the flexural strength and flexural modulus of MWCNT/woven kenaf/
    epoxy composites, with obvious reduction trend was shown by former technique. The morphological observation of the
    composites fracture surface showed that delamination failure occurred in MWCNT/woven kenaf/epoxy laminated composite
    prepared by spraying technique. Further investigation on hybrid composites showed that MWCNT/woven glass/woven
    kenaf/epoxy laminated hybrid composites exhibited significant improvement in the flexural properties.
    Matched MeSH terms: Epoxy Resins
  17. Fulltext Enhanced Thermal and Dynamic Mechanical Properties of Synthetic/Natural Hybrid Composites with Graphene Nanoplateletes
    Jesuarockiam N, Jawaid M, Zainudin ES, Thariq Hameed Sultan M, Yahaya R
    Polymers (Basel), 2019 Jun 26;11(7).
    PMID: 31247898 DOI: 10.3390/polym11071085
    The aim of the present research work is to enhance the thermal and dynamic mechanical properties of Kevlar/Cocos nucifera sheath (CS)/epoxy composites with graphene nano platelets (GNP). Laminates were fabricated through the hand lay-up method followed by hot pressing. GNP at different wt.% (0.25, 0.5, and 0.75) were incorporated with epoxy resin through ultra-sonication. Kevlar/CS composites with different weight ratios (100/0, 75/25, 50/50, 25/75, 0/100) were fabricated while maintaining a fiber/matrix weight ratio at 45/55. Thermal degradation and viscoelastic properties were evaluated using thermogravimetric analysys (TGA), differential scanning calorimetric (DSC) analysis, and a dynamic mechanical analyser (DMA). The obtained results revealed that Kevlar/CS (25/75) hybrid composites at 0.75 wt.% of GNP exhibited similar thermal stability compared to Kevlar/epoxy (100/0) composites at 0 wt.% of GNP. It has been corroborated with DSC observation that GNP act as a thermal barrier. However, DMA results showed that the Kevlar/CS (50/50) hybrid composites at 0.75 wt.% of GNP exhibited almost equal viscoelastic properties compared to Kevlar/epoxy (100/0) composites at 0 wt.% GNP due to effective crosslinking, which improves the stress transfer rate. Hence, this research proved that Kevlar can be efficiently (50%) replaced with CS at an optimal GNP loading for structural applications.
    Matched MeSH terms: Epoxy Resins
  18. Fulltext Void Content, Tensile, Vibration and Acoustic Properties of Kenaf/Bamboo Fiber Reinforced Epoxy Hybrid Composites
    Ismail AS, Jawaid M, Naveen J
    Materials (Basel), 2019 Jun 28;12(13).
    PMID: 31261821 DOI: 10.3390/ma12132094
    This study aims to investigate the void content, tensile, vibration and acoustic properties of kenaf/bamboo fiber reinforced epoxy hybrid composites. The composites were made using the hand lay-up method. The weight ratios of kenaf/bamboo were 30:70, 50:50 and 70:30. Further, kenaf and bamboo composites were fabricated for the purpose of comparison. The hybridization of woven kenaf/bamboo reduced the void content. The void contents of hybrid composites were almost similar. An enhancement in elongation at break, tensile strength and modulus of hybrid composites was observed until a kenaf/bamboo ratio of 50:50. Kenaf/bamboo (50:50) hybrid composite displays the highest elongation at break, tensile strength and modulus compared to the other hybrid composites which are 2.42 mm, 55.18 MPa and 5.15 GPa, respectively. On the other hand, the highest natural frequency and damping factors were observed for Bamboo/Kenaf (30:70) hybrid composites. The sound absorption coefficient of composites were measured in two conditions: without air gap and with air gap (10, 20, 30 mm). The sound absorption coefficient for testing without air gap was less than 0.5. Introducing an air gap improved the sound absorption coefficient of all composites. Hence, hybrid kenaf/bamboo composites exhibited less void content, as well as improved tensile, vibration and acoustic properties.
    Matched MeSH terms: Epoxy Resins
  19. Fulltext Evaluation of Interfacial Fracture Toughness and Interfacial Shear Strength of Typha Spp. Fiber/Polymer Composite by Double Shear Test Method
    Ikramullah, Rizal S, Nakai Y, Shiozawa D, Khalil HPSA, Huzni S, et al.
    Materials (Basel), 2019 Jul 10;12(14).
    PMID: 31295885 DOI: 10.3390/ma12142225
    The aim of this paper is to evaluate the Mode II interfacial fracture toughness and interfacial shear strength of Typha spp. fiber/PLLA and Typha spp. fiber/epoxy composite by using a double shear stress method with 3 fibers model composite. The surface condition of the fiber and crack propagation at the interface between the fiber and the matrix are observed by scanning electron microscope (SEM). Alkali treatment on Typha spp. fiber can make the fiber surface coarser, thus increasing the value of interfacial fracture toughness and interfacial shear strength. Typha spp. fiber/epoxy has a higher interfacial fracture value than that of Typha spp. fiber/PLLA. Interfacial fracture toughness on Typha spp. fiber/PLLA and Typha spp. fiber/epoxy composite model specimens were influenced by the matrix length, fiber spacing, fiber diameter and bonding area. Furthermore, the interfacial fracture toughness and the interfacial fracture shear stress of the composite model increased with the increasing duration of the surface treatment.
    Matched MeSH terms: Epoxy Resins
  20. Fulltext Nano-Level Damage Characterization of Graphene/Polymer Cohesive Interface under Tensile Separation
    Koloor SSR, Rahimian-Koloor SM, Karimzadeh A, Hamdi M, Petrů M, Tamin MN
    Polymers (Basel), 2019 Sep 02;11(9).
    PMID: 31480660 DOI: 10.3390/polym11091435
    The mechanical behavior of graphene/polymer interfaces in the graphene-reinforced epoxy nanocomposite is one of the factors that dictates the deformation and damage response of the nanocomposites. In this study, hybrid molecular dynamic (MD) and finite element (FE) simulations of a graphene/polymer nanocomposite are developed to characterize the elastic-damage behavior of graphene/polymer interfaces under a tensile separation condition. The MD results show that the graphene/epoxy interface behaves in the form of elastic-softening exponential regressive law. The FE results verify the adequacy of the cohesive zone model in accurate prediction of the interface damage behavior. The graphene/epoxy cohesive interface is characterized by normal stiffness, tensile strength, and fracture energy of 5 × 10-8 (aPa·nm-1), 9.75 × 10-10 (nm), 2.1 × 10-10 (N·nm-1) respectively, that is followed by an exponential regressive law with the exponent, α = 7.74. It is shown that the commonly assumed bilinear softening law of the cohesive interface could lead up to 55% error in the predicted separation of the interface.
    Matched MeSH terms: Epoxy Resins
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