Siti Shuhadah Md Saleh
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Siti Shuhadah Md Saleh
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Siti Shuhadah, Md Saleh
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Siti Shuhadah, M. S.
Saleh, Siti Shuhadah Muhammad
Md Saleh, S.S
Saleh, S.S.M.
Siti Shuhadah, M.S.
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57212339952

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The total phenolic content, total flavonoid content and antioxidant properties of E.tirucalli L. extract partitioned using different solvents

2025 , Mangalagowri Sangar , Nur Farahiyah Mohammad , Siti Shuhadah Md Saleh , Alwani Ibrahim , Farah Diana Mohd Daud , Roy Francis Navea , Khairul Farihan Kasim , Nashrul Fazli Mohd Nasir

E.tirucalli L. is a succulent plant native to Africa renowned for its medicinal properties and antioxidant activity. This study aimed to evaluate the total phenolic and flavonoid content as well as the antioxidant activity of E.tirucalli L. extracts obtained using different solvents. Aqueous ethanol, hexane, and dichloromethane were used for extraction through Soxhlet extraction and partitioning. The total phenolic content was highest in the aqueous ethanol extract (2.501 mg GAE/g), followed by hexane (0.110 mg GAE/g) and dichloromethane (0.050 mg GAE/g) extracts. Similarly, the total flavonoid content was highest in the aqueous ethanol extract (1.307 mg QE/g), followed by hexane (0.164 mg QE/g) and dichloromethane (0.061 mg QE/g) extracts. The DPPH assay demonstrated that the aqueous ethanol extract exhibited the highest radical scavenging activity (RSA) with an IC50 value of 36.89 ± 0.05 μg/mL, followed by dichloromethane (50.94 ± 0.39 μg/mL) and hexane (62.42 ± 1.34 μg/mL) extracts. These findings indicate that aqueous ethanol is an effective solvent for extracting phenolic and flavonoid compounds with potent antioxidant activity from E.tirucalli L. extracts.

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Preparation of Carbon Nanotubes/Alumina Hybrid-Filled Phenolic Composite with Enhanced Wear Resistance

2023-04-01 , Siti Shuhadah Md Saleh , Mohd Firdaus Omar , Akil H.M. , Kudus M.H.A. , Mohd. Mustafa Al Bakri Abdullah , Sandu A.V. , Vizureanu P. , Khairul Anwar Abdul Halim , Mohamad Syahmie Mohamad Rasidi , Syarifah Nuraqmar Syed Mahamud , Sandu I. , Nosbi N.

Hybrid fillers can be produced via various methods, such as physical mixing and chemical modification. However, there is a limited number of studies on the effect of hybridisation on the mechanical performance of hybrid filler-reinforced polymer composites, especially in the context of wear performance. This study investigated the wear resistance of carbon nanotubes (CNTs)/alumina hybrid-filled phenolic composite, where two hybrid methods were used to produce the CNTs/alumina hybrid filler. The CNTs/alumina (CVD hybrid) was synthesised using the chemical vapour deposition (CVD) method, whereas the CNTs-/alumina (physically hybrid) was prepared using the ball milling method. The CNTs/alumina hybrid filler was then used as a filler in the phenolic composites. The composites were prepared using a hot mounting press and then subjected to a dry sliding wear test using a pin-on-disc (POD) tester. The results show that the composite filled with the CVD hybrid filler (HYB composite) had better wear resistance than the composite filled with physically hybrid filler (PHY composite) and pure phenolic. At 5 wt%, the HYB composite showed a 74.68% reduction in wear, while the PHY composite showed a 56.44% reduction in wear compared to pure phenolic. The HYB composite exhibited the lowest average coefficient of friction (COF) compared to the PHY composite and pure phenolic. The average COF decreased with increasing sliding speeds and applied loads. The phenolic composites’ wear and average COF are in the order HYB composite < PHY composite < pure phenolic under all sliding speeds and applied loads.

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Molecular Interactions between polyurethane and UiO-66 in Polymer-MOF nanocomposites: microstructural and mechanical effects

2025 , Mohd Firdaus Omar , Shayfull Zamree Abd. Rahim , S. Ahmad , E.M. Mahdi , Khairul Anwar Abdul Halim , H. Md Akil , N. Nosbi , N. Yudasari , M.H. Hassan , M.B.H. Othman , Siti Shuhadah Md Saleh

The demand for polymer-based nanocomposite-reinforced nanoporous materials is becoming essential in sustainable development studies. Integrating nanoporous materials such as Metal-Organic Frameworks (MOFs) in polymer matrices is essential for developing sustainable advanced materials. Combining MOFs and polymer matrices can produce a hybrid material with improved mechanical strength and stability relative to its constituents. This study aims to elucidate the effect of synthesised UiO-66 nanoparticles in a polyurethane (PU) matrix on the subsequent hybrid materials' microstructural and mechanical properties. UiO-66 nanoparticles were synthesised at 120°C, 130°C, and 140°C. The nanoparticles and subsequent nanocomposite were characterised using X-ray Diffraction (XRD), Fourier Transform Infrared Spectroscopy (FT-IR), Brunauer-Emmett-Teller (BET), and Field Emission-Secondary Electron Microscopy (FE-SEM). The experimental findings indicate that the UiO-66 nanoparticles synthesised at 130°C exhibited a highly desirable crystal structure and effective adsorption properties, and the nanoparticles synthesised at this temperature were then used to reinforce PU, forming a polymer-MOF nanocomposite. The mechanical properties of the resulting nanocomposite were determined using tensile and nanoindentation tests. The UiO-66 nanoparticles were incorporated into PU matrices at various weight percentages (10 wt.%, 20 wt.%, 30 wt.%, and 40 wt.%) via the solution casting technique. The results indicated that 30 wt.% UiO-66 in the polymer nanocomposite exhibits the best mechanical properties, and loading the polymer nanocomposite beyond 30 wt.% is more likely to result in nanoparticle agglomeration and brittle behaviours.

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Quantification of polyphenols content and antioxidant activity of Euphorbia Tirucalli l. extracted using Maceration and Soxhlet method

2025 , Alwani Ibrahim , Nur Farahiyah Mohammad , Siti Shuhadah Md Saleh , Nashrul Fazli Mohd Nasir , Khairul Farihan Kasim , Mangalagowri Sangar , Farah Diana Mohd Daud , Roy Francis Navea

Euphorbia tirucalli L. (E. tirucalli) has gained attention for these past few years in terms of its phytochemical studies due to the antioxidant attribution of polyphenols source as its bioactive compounds in extracts. In order to extract important plant compounds, conventional extraction methods such as maceration and Soxhlet are still widely incorporated for plant extraction techniques due to their convenient application in laboratory settings. This study focused on the two conventional techniques; maceration and Soxhlet on polyphenols extraction of E. tirucalli using various extraction solvents. In order to provide insight into its potential for polyphenols extraction, yield percentage (%) and phytochemical tests such as Total Phenolic Content (TPC), Total Flavonoid Content (TFC), and antioxidant activity (%) were assessed. In terms of yield percentage, Soxhlet methanolic extract was found to be the best. The findings also suggest that both maceration and Soxhlet techniques are effective in extracting a significant amount of phenolics and flavonoid content in which highest value recorded were 17.26 ± 0.23 mgGAE/100g and 50.08 ± 1.13 mgQE/100g for maceration while 16.17 ± 0.21 mgGAE/100g and 43.02 ± 0.01 mgQE/100g for Soxhlet. Maceration with methanol solvent appears to be more effective for TPC and TFC while Soxhlet acetonic extract is chosen as the best for antioxidant activity with 75 .79 ± 0.04 % of radical scavenging activity in E. tirucalli extract. Thus, this study indicates the noteworthy potential of both maceration and Soxhlet techniques for polyphenols extraction.

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Preparation of carbon nanotubes/alumina hybrid-filled phenolic composite with enhanced wear resistance

2023 , Siti Shuhadah Md Saleh , Mohd Firdaus Omar , Hazizan Md Akil , Muhammad Helmi Abdul Kudus , Mohd. Mustafa Al Bakri Abdullah , Andrei Victor Sandu , Petrica Vizureanu , Khairul Anwar Abdul Halim , Mohamad Syahmie Mohamad Rasidi , Syarifah Nuraqmar Syed Mahamud , Ion Sandu , Norlin Nosbi

Hybrid fillers can be produced via various methods, such as physical mixing and chemical modification. However, there is a limited number of studies on the effect of hybridisation on the mechanical performance of hybrid filler-reinforced polymer composites, especially in the context of wear performance. This study investigated the wear resistance of carbon nanotubes (CNTs)/alumina hybrid-filled phenolic composite, where two hybrid methods were used to produce the CNTs/alumina hybrid filler. The CNTs/alumina (CVD hybrid) was synthesised using the chemical vapour deposition (CVD) method, whereas the CNTs-/alumina (physically hybrid) was prepared using the ball milling method. The CNTs/alumina hybrid filler was then used as a filler in the phenolic composites. The composites were prepared using a hot mounting press and then subjected to a dry sliding wear test using a pin-on-disc (POD) tester. The results show that the composite filled with the CVD hybrid filler (HYB composite) had better wear resistance than the composite filled with physically hybrid filler (PHY composite) and pure phenolic. At 5 wt%, the HYB composite showed a 74.68% reduction in wear, while the PHY composite showed a 56.44% reduction in wear compared to pure phenolic. The HYB composite exhibited the lowest average coefficient of friction (COF) compared to the PHY composite and pure phenolic. The average COF decreased with increasing sliding speeds and applied loads. The phenolic composites’ wear and average COF are in the order HYB composite < PHY composite < pure phenolic under all sliding speeds and applied loads.

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Measurement of the water absorption on hybrid carbon fibre prepreg waste composite and its impact on flexural performance

2024-08 , Ahmad Ashari Ahmad Shukri , Norlin Nosbi , Mohd Firdaus Omar , Siti Shuhadah Md Saleh , Muhammad Bisyrul Hafi Othman , Norazwana Mohd Najib , Wan Fahmin Faiz Wan Ali

Carbon fibre (CF) prepreg, essential to composites and aircraft, generates waste known as carbon fibre prepreg waste (CFW) due to its limited lifespan. This study investigates recycling CFW through hybridization, milling it into powder and mixing it with epoxy resin and alumina to form hybrid composites. Using Minitab software, optimal compositions were determined from 13 and 20 experimental designs for CFW-EP and CFW-EP-AL, respectively. Results identified 2.5 wt% CFW and 97.5 wt% epoxy resin as optimal for CFW-EP, and 2.5 wt% CFW, 2.5 wt% alumina, and 95 wt% epoxy resin as optimal for CFW-EP-AL. Samples of epoxy resin polymer (EP), carbon prepreg waste reinforced composite (CFW-EP), and carbon prepreg waste reinforced with alumina composite (CFW-EP-AL) were fabricated and tested for moisture absorption and flexural strength, revealing noticeable deterioration over time. These findings highlight the importance of compositional analysis in developing sustainable materials with optimal flexural strength for various applications.

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Effect of chemical modification of eggshells powder filled low density polyetylene composites

2010 , Siti Shuhadah Md Saleh

Eggshells powder filled low density polyethylene (LDPE/ESP) composites were studied. The composites were prepared by using Z-blade mixer at 1800C using a rotor speed of 50 rpm for 6 minutes. Sample of composites were compression moulded, in an electrically heated Hydraulic press. Hot press procedures involved preheating at 1800C for 4 min followed by compression for 2 min at the same temperature and subsequent cooling under pressure for 2 min. It was found that the tensile strength and elongation at break for the composites decreased with the increasing filler loading. Young’s modulus for the composites increases with the increasing filler loading. Then the composites were modified with isophthalic acid (LDPE/ESPI), ethylene diamine-co-isophthalic acid (LSPE/ESPM) and polyethylene-grafted-maleic anhydride (LDPE/ESPPEMAH). It was found that improvement in interfacial adhesion has enhanced the tensile strength and water absorption resistance of LDPE/modified eggshells powder composites compare to LDPE/unmodified eggshells powder composites (LDPE/ESP).Its also increased thermal stability and percent of crystallinity of composites. Better interfacial adhesion between LDPE and eggshells powder are responsible for the improvement of mechanical properties of LDPE/modified eggshells powder composites, as evident by scanning electron microscopy (SEM) on tensile fracture surface of the composites.

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Properties of carbon nanotubes-calcium carbonate hybrid filled epoxy composites

2020-01-01 , Siti Shuhadah Md Saleh , Suhaimi S.M. , Md Akil H. , Nur Farahiyah Mohammad

Carbon nanotubes (CNTs) have a great potential to be used as filler to enhance the mechanical properties of polymer composites due to excellent properties. However, CNTs have limitation of difficult to disperse in polymer matrix. The hybridization of CNTs and inorganic fillers can improve the dispersion and combine their properties in polymer composites. In the present work, the properties of the epoxy composites filled with carbon nanotube-calcium carbonate (CNTs-CaCO3) hybrid, at various filler loading (i.e., 1-5 wt.%) were studied. The CNTs-CaCO3 hybrid fillers were prepared by physically mixing (PHY) method and chemical vapor deposition (CVD) method. The tensile properties and hardness of both composites were investigated at different weight percentages of filler loading. The CNTs-CaCO3 CVD hybrid composites showed higher tensile strength and hardness than the CNTs-CaCO3 PHY hybrid composites. This increase was associated with the homogenous dispersion of CNT–CaCO3 particle filler. The morphological studies of fracture surfaces after tensile test by means of SEM showed homogenous dispersion of CNTs-calcium carbonate CVD hybrid in epoxy matrix. The result shows that the CNTs-calcium carbonate CVD hybrid composites are capable in increasing tensile strength by up to 116.4%, giving a tensile modulus of 40.3%, and hardness value of 39.2% as compared to a pure epoxy.

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