Papers by Keyword: Scanning Electron Microscope (SEM)

Abstract: This study characterized Lygodium circinnatum (Nito), a natural fiber native to the Philippines, using a factorial design of experiments to determine the optimal alkali treatment for enhancing its chemical and mechanical properties. Sodium hydroxide (NaOH) was applied at varying concentrations (2%, 8.5%, and 15%) and soaking times, with conditions evaluated using Minitab 18 software. X-ray diffraction (XRD) was used to assess crystallinity index (CI), identifying 2% NaOH and 0.50-hour soaking as the most effective combination, yielding the highest CI. Fourier transform infrared (FTIR) spectroscopy confirmed a reduction in non-cellulosic compounds after treatment. Morphological changes were observed using scanning electron microscopy (SEM), which revealed smoother surfaces and reduced impurities. Mechanical tests showed increased tensile strength and tensile force, although a slight decrease in cross-sectional area was noted, attributed to the loss of surface material. These results demonstrate that mild alkali treatment significantly improves Nito fiber's structural integrity and performance. The study provides a scientific basis for optimizing natural fiber treatment and highlights the potential of Nito fiber in developing sustainable, high-performance materials for use in various engineering and industrial applications, including composites and biodegradable products.

Abstract: This study explored the effects of glass fiber and granite powder reinforcements on the mechanical properties of Acrylonitrile Butadiene Styrene (ABS) polymer composites produced via injection molding. Four formulations were tested: pure ABS (Batch A), ABS with 10% glass fiber (Batch B), ABS with 10% granite powder (Batch C), and a hybrid of 10% glass fiber and 10% granite powder (Batch D). Mechanical testing included tensile, flexural, compressive, impact strength, and hardness tests. Batch B showed the highest tensile strength (45.76 MPa), outperforming pure ABS (41.6 MPa), whereas the granite powder in Batch C reduced the tensile strength (36.9 MPa). Hybrid Batch D moderately improved the tensile strength (42.54 MPa) but was less effective than glass fiber alone. Batch B exhibited the highest flexural strength, whereas Batch D exhibited the highest compressive strength. The impact resistance decreased for all filled composites, particularly Batch D. Hardness was the highest in Batch D, reflecting greater material rigidity. Morphological analysis confirmed the good filler dispersion, which influenced the observed mechanical properties. Glass fiber proved to be highly effective for tensile, flexural, and hardness improvements, whereas the combination of fillers enhanced the compressive strength and hardness, offering tailored property enhancements for specific applications.

Abstract: Epoxy was loaded with varying concentrations of fly ash and was characterized for its structural properties using XRD and SEM. The XRD results revealed reduction of crystallinity with increase in filler content indicating that the composites are semi crystalline in nature. The SEM images showed that at lower concentration of filler content, fly ash is uniformly distributed within the epoxy and at higher concentrations of fly ash, agglomerates were observed. Mechanical properties such as tensile and compressive properties were estimated and the results showed that, the composites exhibit enhanced tensile strength and compressive strength for epoxy with 20 wt% fly ash. Flammable properties such as heat release rate, peak heat release rate, time to ignition, CO and CO₂ yields are estimated and reported. Decrease in combustion time, peak heat release rate, time to ignition, CO and CO₂ yields with increase in filler content clearly indicates the superior flammability performance of epoxy composites loaded with fly ash.

Abstract: The objective of this article was to study the morphological characteristic and mechanical properties of gypsum boards. The gypsum plaster (GP) type 1 was replaced by water hyacinth fiber (WHF) at the dosages of 0, 50, 75, 100, and 150 by mass. The scanning electron microscopy (SEM) was used to observe their morphological characteristics, whereas mechanical properties of gypsum board were based on the TIS 219-2552. The thermal conductivity (k) was tested by according to ASTM E 1225 standard. Test results found that the morphological characteristics of the WFH showed rather roughness; thus, the voids of WHF increased. The thermal conductivity of gypsum boards incorporated with WHF tended to decrease as the void increased. Finally, it was determined that the water absorption (A_W) and two bending forces (F_L and F_W) of the gypsum board including WHF were insufficient for compliance with the TIS 219-2552 standard.

Abstract: The expansion of the oil palm industry has affected the environment and the poor handling of oil palm waste has greatly endangered the habitat surrounds it. The oil palm natural fibre waste can be put to good use and used as a sound absorber for its amazing acoustic properties. At the same time, the demand for natural fibre sound-absorbing panels is increasing due to its low-cost fabrication and its healthier than synthetic fibre. This research has studied the acoustic properties of mixing Empty Fruit Bunch (EFB) and Oil Palm Frond (OPF) in a thickness of 12 mm, 14 mm, 16 mm, and 18 mm. The fibreboard has been fabricated at a density of 120 kg/m³. The Sound Absorption Coefficient, SAC, and morphologies of all the samples were examined using the Impedance Tube Method (ITM) and Scanning Electron Microscope, (SEM). The sample’s SAC value increased with thickness. It is noteworthy that this combination percentage of natural fibres of EFB and OPF show good acoustic performance where the SAC values above 0.8 at wide frequency 3000 - 6400 Hz. Sample thickness 14 mm, 18 mm achieved unity (1.0) at frequency 4000 - 5500 Hz. In addition, all the samples were found to exceed 90 % of the absorption rate in the range of 4500 - 6400 Hz. The morphology content of EFB and OPF helps in enhancing the absorption rate.

Abstract: In order to understand the crystal defects of beta-gallium oxide (β-Ga₂O₃) in more detail, we classified the crystal defects of a 2-inch substrate of β-Ga₂O₃ (001) single crystal. As a result of observing the etch pits formed by molten alkali etching using scanning electron microscope (SEM) and atomic force microscope (AFM), we succeeded in observing six different etch pit shapes. These etch pit shapes are categorized into “Cicada I type”, “Cicada II type”, “Cannonball type”, “Trapezoid type”, “Bar type”, and “Shell type”. We consider that “Cicada I type” and “Cicada II type” are etch pit shapes caused by planar defects, and “Cannon ball type” is etch pit shapes due to dislocations. In addition, “Trapezoid type”, “Bar type”, and “Shell type” are deduced the result of surface morphology.

Abstract: The scratch damage that caused the generation of double Shockley stacking faults (DSFs) in heavily nitrogen doped 4H-SiC crystal was investigated quantitatively. Scratch tests were carried out on 4H-SiC substrates with a nitrogen concentration of 2.6 × 10¹⁹ cm^-3. A residual tensile stress of 40 MPa was detected around the scratch loaded at 30 mN with a diamond tip. DSFs were generated from this scratch by annealing at 1100°C for 2 h in Ar atmosphere. After annealing, the residual stress around the scratch was reduced to a tensile stress of 10 MPa. This result suggests that the reduction of residual stress around the scratch coincided with the formation of DSFs.

Abstract: Because of their high specific stiffness and strength, fiber reinforced plastics (FRP) are preferred lightweight materials. Recent developments show a growing industrial interest in the integration of thermoplastic FRP in complex structures for high volumes. However, there are still shortcomings for these materials concerning the insufficient energy absorption in case of failure and the limited opportunities available for the assembly with other components. Improvements in the crash performance can be achieved for instance with the selective reinforcement of the FRP structure with ductile metallic inserts. The present study shows the interlaminar shear strength and scanning electron microscope (SEM) samples of a novel load optimized hybrid composite consisting of a continuous fiber-reinforced thermoplastic matrix, in which a metal core is integrated.

Abstract: Moisture absorption of natural fiber-based composites is one of the major problems in outdoor applications. The present study deals with the effect of moisture absorption on mechanical and thermal properties of unmodified/modified Date Palm Leaf (DPL) with glass fiber-based hybrid composites. Natural fibers were modified with alkaline treatment to improve fiber and matrix bonding. Conventional hand lay-up technique is used to fabricate the composites with varying different wt.% of treated and untreated short DPL with constant wt.% of glass fiber and prepared with random oriented manner. The combine effect of hydrophilic and hydrophobic nature find out as the study based upon the natural with synthetic fiber hybrid composites. Mechanical behaviour of the epoxy-based hybrid composites were characterized by using tensile, flexural and hardness test. The results revealed that significant improvement in mechanical properties by the addition of different weight percentage of modified DPL. Different thermal properties of the composites were described by using Thermo Gravimetric Analyzer (TGA) and Differential Scanning Calorimetric (DSC). Morphological investigation was carried out to by using scanning electron microscope. All the properties of untreated natural fiber reinforced composites were mostly affected by the influence of water absorption as compared with chemically treated based composites.

Abstract: This study was designed to examine the consequences of lamination sequence, fiber orientation and hybridization on tensile, flexural, physical, and inter-laminar properties of Jute-epoxy laminated composites and its hybrid. These laminates are partially biodegradable hence environment-friendly. Here six laminated specimens were fabricated using hand lay-up techniques with 4 layers of fiber or 40% fiber loading as per the ASTM standard. Samples were prepared with three different orientation of 0⁰, 30⁰ and 60⁰ to the loading direction. The experimental outcome revealed that composite with 30⁰ fiber orientation gives a better result in flexural, microhardness, and interlaminar shear strength. Generally, Final failure was due to delamination, fiber pull-out, fiber failure or matrix cracking. Scanning electron micrographs were used for improved understanding of fracture mechanics. A substantial quantity of voids, improper alignment, fiber waviness and heterogeneous interface were found resulted in premature failure.