Mohd Firdaus Omar
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Preferred name
Mohd Firdaus Omar
Official Name
Mohd Firdaus, Omar
Alternative Name
Omar, Mohd Firdaus
Mohd, Firdaus Omar
Omar, M. F.
Omar, Mohdfirdaus
Omar, Mohd F.
Main Affiliation
Scopus Author ID
36149536300
Researcher ID
U-8459-2019

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  • Publication
    Improving flexural and dielectric properties of carbon fiber epoxy composite laminates reinforced with carbon nanotubes interlayer using electrospray deposition
    ( 2020)
    Muhammad Razlan Zakaria
    ;
    Hazizan Md Akil
    ;
    Mohd Firdaus Omar
    ;
    Mohd. Mustafa Al Bakri Abdullah
    ;
    Aslina Anjang Ab Rahman
    ;
    Muhammad Bisyrul Hafi Othman
    The electrospray deposition method was used to deposit carbon nanotubes (CNT) onto the surfaces of woven carbon fiber (CF) to produce woven hybrid carbon fiber–carbon nanotubes (CF–CNT). Extreme high-resolution field emission scanning electron microscopy (XHR-FESEM), X-ray diffraction (XRD), Raman spectroscopy and Fourier transform infrared spectroscopy (FT-IR) were used to analyze the woven hybrid CF–CNT. The results demonstrated that CNT was successfully and homogenously distributed on the woven CF surface. Woven hybrid CF–CNT epoxy composite laminates were then prepared and compared with woven CF epoxy composite laminates in terms of their flexural and dielectric properties. The results indicated that the flexural strength, flexural modulus and dielectric constant of the woven hybrid CF–CNT epoxy composite laminates were improved up to 19, 27 and 25%, respectively, compared with the woven CF epoxy composite laminates.
  • Publication
    Enhancement of tensile properties of glass fibre epoxy laminated composites reinforced with carbon nanotubes interlayer using electrospray deposition
    ( 2021)
    Muhammad Razlan Zakaria
    ;
    Mohd Firdaus Omar
    ;
    Hazizan Md Akil
    ;
    Muhammad Bisyrul Hafi Othman
    ;
    Mohd. Mustafa Al Bakri Abdullah
    The introduction of carbon nanotubes (CNTs) onto glass fibre (GF) to create a hierarchical structure of epoxy laminated composites has attracted considerable interest due to their merits in improving performance and multifunctionality. Field emission scanning electron microscopy (FESEM) was used to analyze the woven hybrid GF-CNT. The results demonstrated that CNT was successfully deposited on the woven GF surface. Woven hybrid GF-CNT epoxy laminated composites were then prepared and compared with woven GF epoxy laminated composites in terms of their tensile properties. The results indicated that the tensile strength and tensile modulus of the woven hybrid GF-CNT epoxy laminated composites were improved by up to 9% and 8%, respectively compared to the woven hybrid GF epoxy laminated composites.
  • Publication
    An alkaline deep eutectic solvent based on potassium carbonate and glycerol as pretreatment for the isolation of cellulose nanocrystals from empty fruit bunch
    ( 2020-02-01)
    Gan P.G.
    ;
    Sam Sung Ting
    ;
    Muhammad Faiq Abdullah
    ;
    Mohd Firdaus Omar
    ;
    Tan L.S.
    Cellulose nanocrystals (CNC) were successfully isolated from oil palm empty fruit bunch (EFB) using sulphuric acid hydrolysis preceded by alkaline deep eutectic solvent (DES) pretreatment and bleaching. In this study, an alkaline DES consisting of potassium carbonate and glycerol (molar ratio of 1:7) was used as the pretreatment solvent to promote the dissolution of lignin and hemicellulose. The processing parameters of acid hydrolysis were optimized using Box-Behnken Design. The results showed that the yield of CNC was 37.1%, under the optimal conditions of 60.0 wt% acid concentration at 46.1 °C for 58.5 min. The field emission scanning electron microscopy (FESEM), chemical composition analysis, and Fourier transform infrared (FTIR) results indicated that unwanted impurities, such as hemicellulose and lignin, were efficiently eliminated from the raw EFB fibers by DES pretreatment and bleaching. The average diameter of CNC was less than 10 nm. The raw EFB fiber, treated cellulose, and CNC showed crystallinities of 38.7%, 51.2%, and 65.3%, respectively. The CNC had lower thermal stability, which was ascribed to the sulphate group present on the CNC surface.
      1
  • Publication
    Network Structure and Mechanical Properties of Flexible Electronic Interconnects based on Linear Low-Density Polyethylene (LLDPE) and Liquid Silicone Rubber (LSR) Conductive Polymer Composites
    ( 2024-03-01)
    Khairul Anwar Abdul Halim
    ;
    Mohd Arif Anuar Mohd Salleh
    ;
    Badrul F.
    ;
    Azlin Fazlina Osman
    ;
    Mohd Firdaus Omar
    ;
    Suhaimi A.S.
    ;
    Muhammad Salihin Zakaria
    Conductive polymer composites (CPCs) with the ability to maintain high conductivity whilst remaining flexible at various operating temperatures and conditions have gained interest as potential materials for electronic interconnect applications. The ability of a polymer matrix to conduct electricity is mainly dependent on the conductive filler loadings as well as the formation of network paths within the CPCs. The main aim of this research work was to establish and understand the correlation between the network structure formation and mechanical properties of linear low-density polyethylene/copper (LLDPE/Cu) and liquid silicone rubber/copper (LSR/Cu) CPCs. Various techniques such as electron microscopy, thermal studies, four-point probe, and tensile testing were employed in this study. Furthermore, selected samples were characterized and tested using synchrotron micro-x-ray fluorescence (XRF) technique and dynamic mechanical analysis (DMA). It was found that the electrical conductivity of the CPCs increased with increasing filler loadings. Addition of Cu filler had a marginal effect on the tensile strength of both LLDPE/Cu and LSR/Cu CPCs. Nevertheless, it was found that the elongation at break for LLDPE/Cu consistently increased with the addition of Cu whereas, for LSR/Cu samples, the elongation at break decreased with the addition of Cu at various loadings. The scanning electron microscopy (SEM) micrographs obtained show that the particles of Cu were closer to one another at higher filler loadings. The data obtained revealed the potential for utilizing CPCs as flexible interconnects suitable for advanced electronic applications.
      1
  • Publication
    The effect of synthesis parameter On HKUST-1 nanocomposites studied by FTIR characterisation and mechanical testing
    ( 2024-12)
    Syazwana Ahmad
    ;
    Mohd Firdaus Omar
    ;
    Khairul Anwar Abdul Halim
    ;
    Shayfull Zamree Abd. Rahim
    ;
    Sam Sung Ting
    ;
    E. M. Mahdi
    ;
    Hazizan Md Akil
    ;
    Muhammad Hafiz Hassan
    ;
    Norlin Nosbi
    ;
    Nurfina Yudasari
    In the present work, Hong Kong University of Science and Technology (HKUST-1) has been synthesised at room temperature with 1:0, 1:1 and 0:1 ratio of ethanol and water and reinforced into polyurethane. In order to understand the impact of synthesis parameters on HKUST-1 nanocomposites, an investigation was conducted using FTIR characterisation and mechanical testing. The objective was to examine the potential improvement of the reinforced polymer. The mechanical testing results were shown to be significantly influenced by the presence of HKUST-1 with 1:0 ratio of ethanol and water (sample A) into polyurethane (PU). The samples underwent Fourier Transform Infrared Spectroscopy (FTIR) analysis to determine the types of bonds within the polymer-MOF nanocomposites. It was observed that the reinforced nanoparticles did not undergo any chemical changes, as indicated by the recorded spectra, which can be related to the overlapping characteristics of HKUST-1 and PU. The findings indicate that the A/PU exhibited a notable impact in comparison to other materials, as evidenced by the results of the tensile test and nanoindentation study.
      1  24
  • Publication
    Partially Replacement of Cement by Sawdust and Fly Ash in Lightweight Foam Concrete
    ( 2020-03-18)
    Mohd Firdaus Omar
    ;
    Muhd Afiq Hizami Abdullah
    ;
    Rashid N.A.
    ;
    Abdul Latif Abdul Rani
    The rapid growth of population has led to increased demand for fast, affordable and quality housing development. Today, the construction industry in Malaysia has shifted from conventional methods to Industrial Building Systems (IBS). The most commonly used IBS component is precasat concrete with lightweight foam concrete. This study focuses on the main component of foam lighweight concrete, which is a partially replacement of cement by sawdust and fly ash. Among the features of lightweight concrete is density below 1800 kg/m3. Therefore, the objectives of this study is to determine the effects of sawdust and fly ash as part of cement replacement in terms of mechanical properties (compressive strenght) and physical properties (water absorption). In addition, this study also determine the optimum percentage of cement replacement by sawdust and fly ash in building material. The percentage of saw dust and fly ash used in this study as a partial replacement cement are 5%, 10%, 15% and 20%. The results show that increasing the percentage of mix propotion will increase the water absorption rate as well as decrease the compressive strenght of strength. Also, the density and compressive strength of lightweight foam concrete will decrease as the percentage of partial replacement cement increases. According to JKR Standard Specification for Building Works that referred in Malaysia, the minimum compression strength of lightweight foam concrete allowed for hollow blocks is 2.8 N/mm2. The results obtained from this study show lightweight concrete blocks using saw dust and fly ash as part of the cement replacement meet the standards and can be commercialized in the industrial building system development.
      30  4
  • Publication
    Effect of Using Soap Nut as Natural Foaming Agent on Mechanical Properties and Pore Distribution of High Strength Aerated Concrete
    ( 2020-07-09)
    Muhd Afiq Hizami Abdullah
    ;
    Rashid N.A.
    ;
    Abdul Rani A.L.
    ;
    Mohd Firdaus Omar
    ;
    Tan Chan Sin
    Aerated concrete is a type of concrete that contains pore in its matrix structure. This pores could provide spaces for water absorption which makes aerated concrete more durable toward freeze-thaw cycle. Many methods have been studied in forming an aerated concrete and using soap nut as aerating agent is more sustainable than other chemically formulated agent. Forming of pore inside concrete not only improve freeze-thaw cycle durability but also as places to store healing agent in concrete. This is important in developing a self-healing concrete especially a microbial induced healing. This paper aims to study the effect of using soap nut in high strength concrete. Four types of high strength concrete samples were prepared which are Control sample, AE2 with 2% of aerated soap nut, AE4 with 4% of aerated soap nut and AE6 with 6% of aerated soap nut. Total of 3nos. of 100mm cubes and 3nos. of 50mm cubes from each type of samples were prepared. Cubes samples of 100mm dimension were tested for water absorption and compressive strength while cube samples of 50mm dimension were split and analysed for pore distribution. The results showed that increase in addition of soap nut in concrete mixture resulted in decrease of compressive strength but minimal effect on its water absorption rate. Pore formation and dispersion were optimum in concrete with 4% and 6% inclusion of soap nut. In conclusion, 4% of aerated soap nut in high strength concrete present the optimum characteristic in producing well-dispersed pores of high strength aerated concrete.
      2  33
  • Publication
    Improving flexural and dielectric properties of carbon fiber epoxy composite laminates reinforced with carbon nanotubes interlayer using electrospray deposition
    ( 2020-01-01)
    Muhammad Razlan Zakaria
    ;
    Hazizan Md Akil
    ;
    Mohd Firdaus Omar
    ;
    Mohd. Mustafa Al Bakri Abdullah
    ;
    Rahman, Aslina Anjang Ab
    ;
    Othman, Muhammad Bisyrul Hafi
    The electrospray deposition method was used to deposit carbon nanotubes (CNT) onto the surfaces of woven carbon fiber (CF) to produce woven hybrid carbon fiber-carbon nanotubes (CF-CNT). Extreme high-resolution field emission scanning electron microscopy (XHR-FESEM), X-ray diffraction (XRD), Raman spectroscopy and Fourier transform infrared spectroscopy (FT-IR) were used to analyze the woven hybrid CF-CNT. The results demonstrated that CNT was successfully and homogenously distributed on the woven CF surface. Woven hybrid CF-CNT epoxy composite laminates were then prepared and compared with woven CF epoxy composite laminates in terms of their flexural and dielectric properties. The results indicated that the flexural strength, flexural modulus and dielectric constant of the woven hybrid CF-CNT epoxy composite laminates were improved up to 19, 27 and 25%, respectively, compared with the woven CF epoxy composite laminates.
      2  1
  • Publication
    Self-healable and recyclable nitrile rubber based on thermoreversible ionic crosslink network
    ( 2022-04-15)
    Mohd Hafiz Zainol
    ;
    Ariff Z.M.
    ;
    Mohd Firdaus Omar
    ;
    Ping T.M.
    ;
    Shuib R.K.
    In this work, commercial carboxylated nitrile butadiene rubber (XNBR) was ionically crosslinked with zinc thiolate forming reversible ionic salt bonding between carboxy groups (COOH) in XNBR chains and Zn2+ ions from zinc thiolate. The reversible nature of the ionic crosslinks allows rearrangement of rubber molecular chains under an external heat and provides self-healing capability to the materials. The amount of zinc thiolate was varied at five levels (10, 20, 30, 40, and 50 per hundred rubber (phr) to assess the maximum reaction between COOH and Zn2+ ion for the formation of ionic crosslink networks. Evidence that ionic crosslinks formed within the materials was determined by the increased of curing torque and the chemical interaction was identified by Fourier transform infrared spectroscopy. An equilibrium swelling testing quantitatively measured the ionic crosslink density within the material and XNBR with 30-phr zinc thiolate showed the highest ionic crosslink density. The results revealed that, damaged XNBR with 30 phr zinc thiolate able to recover 98% of its initial properties under thermal healing at 150°C for 10 min. Furthermore, the material can be reprocessed and recycled for three times without compromising its initial properties. Perhaps, the tensile strength increased 360% at approximately 23 MPa, after third recycling process. In addition, the self-healing XNBR also have excellent weldability on the damage sample, which shows high potential for repairing of existing rubber products installed in heavy engineering applications.
      28  1
  • Publication
    Influence of filler surface modification on static and dynamic mechanical responses of rice husk reinforced linear low-density polyethylene composites
    ( 2021)
    Mohd Firdaus Omar
    ;
    Mohd. Mustafa Al Bakri Abdullah
    ;
    Sam Sung Ting
    ;
    B. Jeż
    ;
    M. Nabiałek
    ;
    Hazizan Md Akil
    ;
    Nik Noriman Zulkepli
    ;
    Shayfull Zamree Abd. Rahim
    ;
    Azida Azmi
    Filler surface modification has become an essential approach to improve the compatibility problem between natural fillers and polymer matrices. However, there is limited work that concerns on this particular effect under dynamic loading conditions. Therefore, in this study, both untreated and treated low linear density polyethylene/rice husk composites were tested under static (0.001 s–1, 0.01 s–1 and 0.1 s–1) and dynamic loading rates (650 s–1, 900 s–1 and 1100 s–1) using universal testing machine and split Hopkinson pressure bar equipment, respectively. Rice husk filler was modified using silane coupling agents at four different concentrations (1, 3, 5 and 7% weight percentage of silane) at room temperature. This surface modification was experimentally proven by Fourier transform infrared and Field emission scanning electron microscopy. Results show that strength properties, stiffness properties and yield behaviour of treated composites were higher than untreated composites. Among the treated composites, the 5% silane weight percentage composite shows the optimum mechanical properties. Besides, the rate of sensitivity of both untreated and treated composites also shows great dependency on strain rate sensitivity with increasing strain rate. On the other hand, the thermal activation volume shows contrary trend. For fracture surface analysis, the results show that the treated LLDPE/RH composites experienced less permanent deformation as compared to untreated LLDPE/RH composites. Besides, at dynamic loading, the fracture surface analysis of the treated composites showed good attachment between RH and LLDPE.
      1  16