Papers by Keyword: Nanocomposite

Abstract: Ultraviolet (UV) photodetectors have garnered considerable attention because of their critical roles in diverse technological applications. This study reports the fabrication and characterization of single-walled carbon nanotube (SWCNT)/polyaniline (PANI) nanocomposite films prepared via the spin-coating technique on Indium Tin Oxide (ITO) substrates for ultraviolet (UV) photodetector applications. Two weight concentrations of SWCNTs (0.04 g and 0.06 g) were investigated to assess their influence on the optical and structural properties of the films. Structural consistency was confirmed using scanning electron microscopy (SEM), while UV–visible spectroscopy revealed optical band gaps of 1.60–2.08 eV. Electrical characterization demonstrated that an increased SWCNT content led to an enhanced current response. The device with 0.04 g SWCNT achieved a detectivity of 1.12 × 10¹⁶ Jones and a photoresponsivity of 11.361 μA/mW, with response and recovery times of 0.36 s and 0.34 s, respectively. The 0.06 g SWCNT device showed improved performance, reaching a photoresponsivity of 12.1414 μA/W and detectivity of 1.43 × 10¹⁶ Jones, with response and recovery times of 0.36 s and 0.38 s, respectively. These findings demonstrate the potential of SWCNT/PANI composites for high-performance UV photodetector applications.

Abstract: The present work includes an investigation of the effect of α-alumina nanoparticles addition to aluminum-based nanocomposites on its mechanical properties and finding the optimal value of alumina nanoparticles that give the best properties. Experimental work includes manufacturing samples of aluminum-based nanocomposite reinforced with alumina nanoparticles by powder metallurgy- hot forging process. Mechanical properties were tested. The results show an increase in hardness and compression yield strength with increasing the weight percentage of alumina nanoparticles, while the wear rate decreased to certain percentages of addition and then increased again. From the experimental results, multiple regression analysis methods have been used to obtain an empirical equation for predicting the mechanical properties and describe the behavior of hardness, compression strength, and wear rate. Genetic Algorithm Optimization was applied to find the optimum value of alumina nanoparticles weight percentage which gives good mechanical properties.

Abstract: This study developed the synthesis of Mg_0.5Fe_2.5O₄/chitosan nanocomposite and its application as a drug delivery system. Doxorubicin hydrochloride (DOX), as a model drug, was adsorbed onto the surface of the Mg_0.5Fe_2.5O₄/Chitosan nanocomposite, and its loading and release efficiency was observed using UV-Vis spectroscopy. After synthesizing Mg_0.5Fe_2.5O₄/chitosan nanocomposite, various analytical devices were used to qualify and quantify the nanocomposite, including XRD, FTIR, SEM-EDX, and VSM. The XRD results showed that the Mg dopant was well inserted into the Fe₃O₄ without forming Mg or its oxide phases. The Mg dopant caused shifting of most Fe₃O₄ peaks to lower angles due to the larger atomic radius of Mg (173 pm) compared to Fe (126 pm). The presence of surfactant was confirmed by FTIR spectrum, indicated by the presence of C-H, C=O, C=C, and O-H bonds at wavenumbers 1339, 1735, 1606, and 3460 cm^-1, respectively. An N-H bond from chitosan was also located at a wavenumber of 3271 cm^-1. Mg_0.5Fe_2.5O₄/Chitosan had a spherical shape that tended to agglomerate due to the nanoparticles. VSM characterization results showed the Mg_0.5Fe_2.5O₄/chitosan nanocomposite was superparamagnetic with a saturation magnetization value of 33.84 emu/g. The drug loading experiment showed that the loaded DOX reached 90% and successfully released the drug rapidly by the burst effect in the drug delivery system.

Abstract: Fe₃O₄/Hydroxyapatite (HA)-(3-Aminopropyl)triethoxysilane (APTES) nanocomposite as a drug delivery agent was successfully synthesized. The nanocomposite was characterized using X-ray diffractometry (XRD), scanning electron microscopy (SEM), Fourier transform infrared (FTIR) spectroscopy, vibrating sample magnetometer (VSM), and ultraviolet-visible (UV-Vis) spectroscopy to investigate the structural, morphology, magnetic properties, and DOX drug loading and release efficiency. The XRD pattern of Fe₃O₄ /HA-APTES nanocomposite showed the formation of two phases with cubic spinel structure for Fe₃O₄ and hexagonal structure for HA. The SEM image showed that the nanocomposite morphology tended to be granular (though not perfectly granular) with a particle size distribution of 65.9 nm. The functional groups detected from the FTIR results were Fe-O at 422–602 cm^-1, indicating Fe₃O₄. Furthermore, vibrations of the phosphate group (PO₄^3-) and Si-O-C appeared at 1037 cm^-1 and 1048 cm^-1, which are characteristic of the phosphate stretch in the HA and APTES. The Fe₃O₄/HA-APTES nanocomposite exhibited superparamagnetic properties with a saturation magnetization value of 19.37 emu/g. As a drug delivery agent, the Fe₃O₄/HA-APTES nanocomposite has a DOX loading efficiency of 5.79 mg/g up to 96.51% for eight hours and a release of 16.36% over 300 min.

Abstract: This research has successfully synthesized Fe₃O₄/SWCNT/TiO₂ nanocomposite as a radar absorber for stealth technology applications in the Ka-band. The study aimed to investigate the nanocomposite's crystal structure, morphology, functional groups, magnetic properties, and radar absorption performance at a frequency Ka-Band range from 26.5 GHz to 40.0 GHz. The X-ray diffraction analysis revealed a crystalline phase of Fe₃O₄ with a crystallite size of 14.26 nm and two crystalline phases of TiO₂ (anatase and rutile) with crystallite sizes of 5.12 nm and 27.51 nm, respectively. The scanning electron microscopy image showed SWCNT as a matrix with diameters of several nanometers and lengths of several micrometers, along with Fe₃O₄ and TiO₂ particles as fillers with a particle size of 46.56 nm, consistent with the XRD characterization. Furthermore, the infra-red spectrum confirmed the presence of Fe₃O₄ through octahedral and tetrahedral Fe-O bonds. C-O, C-C, and C=O indicated the presence of SWCNT. Meanwhile, -OH bonds also validated the success of their functionalization. Ti-O and Ti-O-C bonds stated the presence of TiO₂ bound to SWCNTs. The hysteresis curve exhibited superparamagnetic properties of the nanocomposite with a saturation magnetization of 9.38 emu/g. Furthermore, radar absorption measurement demonstrated that the nanocomposite absorbs radar with a maximum reflection loss of –1.51 dB at an effective frequency of 33.16 GHz, showing a potency for Fe₃O₄/SWCNT/TiO₂ nanocomposite as radar absorber in the Ka-Band Region, inspiring potential applications in stealth technology.

Abstract: The current reliance on non-biodegradable plastic packages poses environmental and health hazards from their indiscriminate disposal. This study attempts to fabricate environmentally friendly cellulose nanofibers (CNFs) and carbon dot (HCDs) nanocomposite film from thatching grass waste for potential use in the food packaging industry. CNFs were extracted from Hyparrhenia hirta grass through a series of chemical pretreatments and sulphuric acid hydrolysis, and the carbon dots were synthesized from the extracted nanofibers via solvothermal treatment. The properties of the CNFs and carbon dots were studied using standard scientific techniques, including Fourier transform infrared (FT-IR), Scanning electron microscopy, Raman spectroscopy. The mechanical and water resistance properties of the CNFs/HCDs films were also determined. The results indicate that it is possible to fabricate a flexible and elastic CNFs/HCDs film suitable for packaging applications. The water contact angle measurement for the CNFs/HCDs films also revealed that the surface of the films was hydrophobic, making them suitable for packing dry foods and potentially electronics. Future studies will focus on optimizing the CNFs/HCDs ratio in the chitosan matrix, as the most promising ratio identified so far is 80:20 (film F2).

Abstract: Polymer coatings are thin layers of corrosion protection that can be applied to welded steel. Developing a polyester-based coating with metal fillers could assist homogeneous dispersion on weld surfaces. This study develops and characterizes the unsaturated polyester-Cu-Zn-Al₂O₃ coating and its corrosion performance on the welded steel. Cu-Zn-Al₂O₃ reinforcement was first milled at 40 h at 300 rpm, mixed with polyester to produce a film, and coated on welded steel. The results showed that milled consists of nanostructure and various particle distributions. The composition of the film consists of two distinct materials: amorphous polyester and crystalline Cu, Zn, and Al₂O₃. The ratio of these materials within the film influences its properties. The amount of filler in the polyester-Cu-Zn-Al₂O₃ composite film was maximum at 2.0 wt%. The corrosion rate monitored from 5 to 20 days shows a consistent trend, with 2.0 wt% showing the highest corrosion resistance.

Abstract: Green synthesis of zinc oxide nanoparticles (ZnO NPs) using ethanol extract of avocado fruit (Persea americana) peel with zinc nitrate hexahydrate as ZnO precursor has been conducted. Phytochemicals contained in the ethanol extract of avocado fruit peels such as flavonoids, alkaloids, terpenoids, saponins and phenolics acted as reducing agents, stabilizers and capping agents in green synthesis of ZnO NPs. ZnO NPs further were modified with 1 wt% of activated carbon (AC) derived from melinjo seed shell using hydrothermal method and was evaluated on degradation of chlorpyrifos pesticide. The structural, morphological and optical properties of ZnO NPs, activated carbon and 1 wt % of activated carbon/ZnO (1 wt %-AC/ZnO) nanocomposite were characterized by using the X-Ray Diffraction (XRD) instrument, Scanning Electron Microscopy-Energy-Dispersive X-Ray Spectroscopy (SEM-EDS), Diffuse Reflectance Spectroscopy UV-Vis (DRS UV-Vis) and Brunaeur Emmet Teller (BET). The result showed that the synthesized ZnO NPs were in the zincite crystal phase, while the activated carbon obtained was in amorphous phase. The addition of 1 wt% activated carbon into ZnO NPs caused a decrease in the band gap energy of ZnO NPs. The photocatalytic activity evaluation showed that 1 wt %-AC/ZnO nanocomposite has higher activity than that of bare ZnO NPs. The 1 wt %-AC/ZnO nanocomposite can degrade 90.11% of chlorpyrifos compare with bare ZnO NPs that only degrade 79.30% of chlorpyrifos. The photodegradation evaluation of chlorpyrifos were conducted in the same condition by using 300 mg of 1 wt %-AC/ZnO nanocomposite, the initial pH of chlorpyrifos solution was 7, the initial concentration of chlorpyrifos was 6 mg/L, and the irradiation time under UV light was 4 hours.

Abstract: The green synthesis of TiO₂ nanoparticles (TiO₂ NPs) and their modification with activated carbon (AC) derived from nutmeg (Myristica fragrans) seed shell as photocatalyst for photodegradation of chlorpyrifos pesticide has been successfully conducted. TiO₂ NPs were synthesized using orange peel extract that play a pivotal role as bioreductor, stabilizers and capping agent in synthesis of TiO₂ NPs with titanium tetraisopropoxide as a precursor. The carbonized nutmeg shell was activated using NaOH solution and the activated carbon/TiO₂ (AC/TiO₂) nanocomposite was prepared by hydrothermal method. The crystallinity, average crystallite size, and anatase structure of TiO₂ are established by X-ray diffraction (XRD), while the morphology and optical property of synthesized materials was analysis by using Scanning Electron Microscopy (SEM), Fourier Transform Infrared (FTIR) spectroscopy and UV-vis diffuse reflectance spectroscopy (UV-Vis DRS). The average crystallite size of 7.5 wt%-AC/TiO₂ nanocomposite was a little bigger than that of TiO₂ NPs. Photodegradation of chlorpyrifos was selected as a model reaction to evaluate the photocatalytic activity of 7.5 wt%-AC/TiO₂ nanocomposite. The results showed that 7.5%-AC/TiO₂ nanocomposite can degrade the chlorpyrifos solution up to 81% after irradiated under UV light for 6 hours at the initial mass of photocatalyst was 250 mg and initial chlorpyrifos concentration was 6 ppm. The photocatalytic activity of 7.5%-AC/TiO₂ nanocomposite was higher than that of bare TiO₂ NPs.

Abstract: In the realm of civil engineering, scientists and engineers are striving to enhance the performance of Portland cement concrete (PCC) by incorporating organic waste materials, particularly wheat straw fibers. These fibers, alongside polymers, are key components in reinforcing cementitious concrete. They have been extensively studied and found to positively impact plain concrete, leading to the development of fiber-reinforced concrete (FRC). This study innovates construction through unique random fiber inclusion, diverse types, and addressing maintenance overlays of rigid pavements. This concept resembles a two-sided coin, with one side involving the random integration of fibers into the matrix, commonly seen in applications like Portland cement concrete pavement slabs and canal lining. Extensive research efforts were undertaken to gather insights into the significance of fiber composites in the field of construction. This literature review examines papers published by well-regarded publishers, encompassing the latest and essential research findings. Consequently, the primary aim of this study is to consolidate the outcomes and hurdles associated with fiber-reinforced composites for rigid pavement overlays, offering practical solutions to optimize concrete for enhanced pavement performance and sustainability. Our study's primary goal is to investigate the alterations in wheat straw fiber-reinforced concrete (WSFRC) materials through random fiber inclusion and explore the implications of different fiber types, mixing procedures, and construction challenges. A comprehensive literature review reveals three main objectives for incorporating fibers into concrete pavement overlays: enhancing mechanical properties, developing electrically conductive mixtures, and providing a sustainable solution for waste fiber management. This research paves the way for improving the performance and sustainability of concrete pavements in civil engineering.