Reduced GO decorated waste Moringa oleifera fiber composite for sustainable electromagnetic shielding material

Reduced GO decorated waste Moringa oleifera fiber composite for sustainable electromagnetic shielding material | Research Square window.SnipcartSettings = { analytics: { enabled: false } }; (function() { var accessVector = localStorage.getItem('access_vector') || ''; window.dataLayer = window.dataLayer || []; if (accessVector) { window.dataLayer.push({ user: { profile: { profileInfo: { snid: accessVector } } } }); } })(); (function(w,d,s,l,i){w[l]=w[l]||[];w[l].push({'gtm.start':new Date().getTime(),event:'gtm.js'});var f=d.getElementsByTagName(s)[0],j=d.createElement(s),dl=l!='dataLayer'?'&l='+l:'';j.async=true;j.src='https://www.googletagmanager.com/gtm.js?id='+i+dl;f.parentNode.insertBefore(j,f);})(window,document,'script','dataLayer','GTM-K279D39R'); Browse Preprints In Review Journals COVID-19 Preprints AJE Video Bytes Research Tools Research Promotion AJE Professional Editing AJE Rubriq About Preprint Platform In Review Editorial Policies Our Team Advisory Board Help Center Sign In Submit a Preprint Cite Share Download PDF Research Article Reduced GO decorated waste Moringa oleifera fiber composite for sustainable electromagnetic shielding material Ganeswar Nath, Biswabandita Samantara, Rajib Barik This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-4485842/v1 This work is licensed under a CC BY 4.0 License Status: Published Journal Publication published 17 Nov, 2024 Read the published version in Waste and Biomass Valorization → Version 1 posted 5 You are reading this latest preprint version Abstract The advent of the ultra-first digital system marked a transformative era in technology, particularly in monitoring natural phenomena through electromagnetic waves. For safeguard of the electronic instruments and mitigate electromagnetic interference, the utilization of electromagnetic absorbing materials has emerged as a crucial solution. In this context, the Moringa Oleifera fiber (MOF) which is exploded away as a waste material has the potential to disseminate the intensity of high intense electromagnetic wave plays a crucial role in presence of reduced graphene oxide (rGO) with epoxy as (rGO/MOF/EPOX) composite stand out as a promising approach. When incorporated into an epoxy matrix, MOF form a synergistic blend that not only provides electromagnetic shielding but also offers mechanical strength and stability. The change of complex permittivity of the material from 3.2 to 3.35 with 1wt% of rGO, produces a remarkable reflection loss along with increase of absorption efficiency from 68.38 % to 87.41%.The morphology of rGO/MOF/EPOX composite are analyzed through SEM which supports the ability of the composite to be a good electromagnetic shielding material. The physical, mechanical and thermal property MOF/EPOX composite has been evaluated in presence of rGO and discussed with correlation of dielectric properties of the material. Waste Moringa peel fiber electromagnetic interference reflection loss complex permittivity electromagnetic shielding Figures Figure 1 Figure 2 Figure 3 Figure 4 Figure 5 Figure 6 Figure 7 Figure 8 Figure 9 Figure 10 Figure 11 Statement of Novelty RGO/MOF/EPOX composite a novel and versatile solution for electromagnetic absorption, combining the benefits of natural fiber reinforcement, synergistic electromagnetic properties, biodegradability, and cost-effectiveness. The highly conductive nature of rGO, coupled with the dielectric properties of MO fiber, enhances the absorption of electromagnetic waves across a wide frequency range. This synergistic interaction results in improved absorption performance compared to composites containing only one of these components. Introduction The evolution of internet of things (IoT) based electronic gadgets and its implementation in everyday life as well as in high security places generates the complex electronic pollution in the open environment. The issue of electronic pollution now a day’s plays major role in the technology system as well as human health. Consequently, there are growing concerns about the potential for 5G signals to interfere with existing communication systems, such as radio, television, and satellite transmissions, in defense system as well as with biological organisms and ecosystems. This introduction sets the stage for a deeper exploration of the potential environmental impacts of 5G networks and the need for effective mitigation strategies to address electromagnetic interference/pollution[ 1 , 2 ].The selection of electromagnetic (EM) shielding material is crucial, with an emphasis on compactness, lightweight, ease of manufacture, and sustainability over reflective types. As EM shielding materials are essential across diverse industries, ensuring proper functionality and reliability of electronic devices their manufacturing process meets the challenges for its effectiveness for which it depends on the composition of material along with its sustainability and eco-friendliness with environment[ 3 , 4 ].Challenges linked to conventional ferrite electromagnetic absorbers include limitations in frequency range effectiveness, bulkiness, and weight. Traditional ferrite materials are often most effective within specific frequency bands, limiting their versatility across a broader spectrum. Additionally, their inherent bulk and weight can pose practical challenges, especially in applications requiring lightweight and compact solutions. Moreover, traditional ferrite absorbers may exhibit performance degradation under extreme environmental conditions, such as high temperatures or mechanical stress, impacting their reliability and durability. These issues highlight the need for alternative materials and designs to overcome the limitations associated with traditional ferrite electromagnetic absorbers. Natural fibers offer several advantages that can address the challenges posed by conventional ferrite electromagnetic absorbers. By carefully selecting and processing natural fibers, it's possible to create composites that exhibit absorption across a wider spectrum of frequencies, increasing their versatility and applicability in various electromagnetic shielding applications. Furthermore, natural fibers can be combined with other materials, such as conductive coatings or nanoparticles, to enhance their electromagnetic absorption properties further. This approach allows for the customization of natural fiber-based composites to meet specific performance requirements and overcome the limitations of traditional ferrite absorbers. In the present work MOF waste contributes a unique combination of structural features that render them highly valuable as reinforcements in various applications. Drumstick fibers possess a distinctive set of structural attributes that make them particularly well-suited for applications requiring microwave absorption. Their high aspect ratio and fibrillar microstructure facilitate efficient interaction with electromagnetic waves, enhancing absorption capabilities. Additionally, the cellulose composition and natural lignin content contribute to the dielectric properties of drumstick fibers, optimizing their ability to dissipate microwave energy. The porous structure further aids in the absorption process by promoting multiple reflections and attenuating microwave signals. Furthermore, the flexibility and uniformity of drumstick fibers allow for their incorporation into microwave-absorbing materials without compromising mechanical integrity, ensuring consistent performance across different frequencies and environmental conditions. Incorporating reduced graphene oxide (rGO) into natural fiber-based composites has sparked innovation in functional material development has wide range of applications. Its lightweight nature, cost-effectiveness, and high performance make it attractive filler for advanced composites. By introducing rGO to carbonaceous materials, the molecular and structural composition undergoes modification, resulting in improved abilities to capture electromagnetic waves (EMW) through various mechanisms and interfacial polarizations which leads to exceptional electromagnetic shielding performance[ 4 ].The compatibility between reduced graphene oxide (rGO) and drumstick fiber lies in their complementary properties and potential synergies[ 5 – 7 ]. Drumstick fibers offer mechanical reinforcement and dielectric properties, while rGO contributes high electrical conductivity and a large surface area. The work ensemble have well studied the electromagnetic shielding performance of MOF with incorporation of rGO through analysis of different parameter like complex permittivity, loss tangent, reflection loss. Further, to support the microwave characteristics, the mechanical property like hardness and physical properties such as thermal conductivity and moisture absorption of the raw material as well as composite has been ornamented. There is no such work is reported till today on the waste material of MOF which has been taken in the present context as reinforced material for composite with rGO, except some work on mechanical property and its food value has been studied by some authors[ 8 – 13 ].Thus the present work may provide be an alternative potential candidate for electromagnetic shielding application in design of stealth material. Material and methodology Materials for fabrication Drumstick fiber composites were prepared by collecting waste drumstick raw materials from local areas. Reduced Graphene Oxide (rGO) from SHILPENT enterprises, boasting a purity level exceeding 98%, was used as a coating filler material. The rGO had varying diameters between 10 to 15 µm and thickness ranging from 10 to 15 nm. Sodium hydroxide (NaOH) was employed as a surfactant for surface treatment of the raw fibers. Epoxy-LY556 and Hardener-HY951, mixed at a ratio of 10:1, served as the matrix and binding agent for the fibers. A pure aluminum mold (Jindal-344, 15 cm × 15 cm × 1 cm) was utilized for fabricating bulk drumstick fiber composites, with specific dimensions (23 mm × 11 mm × 3 mm) for the X-Band sample[ 14 ]. 1 mm thick teflon sheet was used to cover the mold to facilitate easy removal of the composite, while silicon oil spray was applied to coat the molding area. Surface treatment and coating of rGO on raw MO fiber The collected raw drumstick fibers were thoroughly splashed with running water to eliminate debris. The washed drumstick fibers were placed in sunlight for a week to enhance the smooth extraction of raw fibers. Then, the fibers were seized into approximately 5–10 cm in length followed by a combing process. The raw combined fibers were immersed in a beaker containing alkaline solution prepared by dissolving NaOH pallets in distilled water under sonication operated at frequency of 125 KHz and 60W power. The treated fibers were further cleaned with distilled water to remove the deposition of NaOH solution from the surface of the fiber if any. This cleaning changes the surface color of the fiber with enhanced surface area of the fiber modifying the surface become highly rough for better binding of fibers with matrix. With the help of a mechanical stirrer the coating of drumstick fiber with industrial graded rGO has been performed. The mechanical stirrer was operated with 600rpm for 30 minutes to disperse the rGO powder uniformly over the drumstick fiber. Finally, a mixture of resin and hardener, at a ratio of 10:1, was combined with the 10% volume fraction of fibers containing 1wt% rGO. The stirring speed was reduced to 100rpm to prevent the formation of gas bubbles until a homogeneous liquid mixture was achieved within which the treated drumstick fibers were well impregnated by rGO within the mixture. The details fabrication process for composite has been shown in Fig. 1 . Characterization and experimental measurement To characterize MOF for their potential use in microwave absorption, several analytical techniques are employed. The morphological changes in the rGO added composite and their composition are investigated by utilizing HITACHI, FLEX SEM, 1000II to perform SEM. The porous structure, surface roughness, fiber orientation, and rGO aggregation on the fiber surface are all revealed by the SEM investigation of the composite. The compositional changes occurred in the MOF before and after the treatment has been well studied with the analysis of FTIR spectroscopic studies. To find out more about the microstructure of these anisotropic and heterogeneous materials, LEICA make optical microscopy is used. The fibrous nature of MOF and their rGO-coated composites has been performed to exactly know the extent of hydrophilicity for moisture resistance, performance of material under humid or wet conditions, for predicting the durability and longevity ,effect of RGO coating on improvement in moisture resistance due to the RGO layer, to predict and optimize the performance of the materials in microwave absorption applications, in electronic and electromagnetic applications, low water absorption is preferred to prevent degradation of properties has been investigated through water absorption test as per the ASTM-D5529 standard. In mechanical characterization, roughness and hardness test of the material has been performed. The Vickers hardness test, following the ASTM E384 standard, employs a 136° pyramidal diamond indenter to create a square-shaped indentation. A load is applied for 10 seconds, after which the two diagonals of the diamond-shaped indentation are measured in millimeters. The average of these measurements, denoted as dimension 𝑑, is used to determine the hardness value. Result and Discussion FTIR Analysis Noticeable changes in the intensity and position of the peaks, reflecting the chemical changes due to NaOH treatment of Moringa fiber as shown in Fig. 2 . Broad Peak around 3400 cm⁻¹ may corresponds to O-H stretching vibrations[ 15 ]. NaOH treated fiber shows a shift or change in intensity, indicating alteration in hydroxyl groups. Peaks around 2900 cm⁻¹ may associated with C-H stretching vibrations[ 15 ]. Changes in these peaks after treatment suggest modifications in the aliphatic content of the fibers. Peak around 1600 cm⁻¹ to 1500 cm⁻¹ may related to aromatic C = C stretching[ 15 ]. Alterations in this region can indicate changes in the aromatic content or structure of lignin. Peaks in the 1300 − 1000 cm⁻¹ range represent C-O stretching and C-H bending[ 16 , 17 ]. Changes in this region for NaOH treated fiber indicate modifications in cellulose and hemicellulose structures. Changes in the peak intensity around 1021 cm⁻¹ after NaOH treatment suggest alterations in the fiber's polysaccharide content[ 18 ]. NaOH treatment typically results in the removal of hemicellulose and partial removal of lignin, leading to an increase in the relative content of cellulose. This is reflected in the FTIR spectrum as changes in the C-O stretching region. NaOH treatment typically removes hemicellulose, lignin, and other extractives, leading to an increase in cellulose content and alteration in functional groups, as evidenced by the changes in peak positions and intensities[ 19 ]. The removal of hemicellulose and lignin increases the porosity and surface area of the fibers. Additionally, the increase in the relative cellulose content, lead to more ordered crystalline structure. This increased surface area and reduction in lignin content leads to enhance dielectric properties for better interaction with microwave radiation, leading to improved absorption capabilities[ 20 ]. Structural & Morphological Analysis The SEM images of the MOF/EPOX composite demonstrate a well-mixed and uniformly distributed epoxy resin across the fiber surfaces. The smooth dispersion of epoxy on the fiber surfaces, with no visible voids at the interfaces, indicates strong adhesion between the fiber and matrix, which is crucial for effective load transfer. Figure 3 (a) and Fig. 3 (b) show the random orientation of fibers within the composite, which may contribute to non-uniform mechanical properties. The epoxy matrix appears in continuous phase with minimal voids or air gaps. The presence of these voids in the matrix can influence the electric field behavior and polarization effects within the composite. These voids can lead to multiple scattering of microwaves, increasing the path length of incident waves and promoting more absorption. Additionally, the presence of air in these voids can enhance impedance matching, leading to better absorption[ 21 ]. However, the presence of voids can also compromise the mechanical strength of the composite, making controlled distribution of voids crucial during fabrication. In some areas of the composite, epoxy-fiber fractures with rough surfaces are observed[ 21 , 22 ]. These fractures increase the irregular surface area and create air gaps, contributing to dielectric loss mechanisms due to the interaction of incident microwaves with the discontinuities, resulting in more random scattering and absorption. Figure 3 (c) shows the SEM image of an rGO-reinforced MOF/EPOX composite. The well-dispersed rGO at the fiber-matrix interface facilitates improved interfacial bonding, leading to effective load transfer. The uniform distribution of rGO across the fiber surfaces is critical for enhancing the mechanical properties of the composite material. The well-dispersed and firmly adhered rGO particles to the fiber surface could be a result of sonication processes during impregnation. The incorporation of rGO into the composite forms more effective network of conductive pathways and creates additional interfacial regions, enhancing the dielectric properties and contributing to improved conductive loss. The SEM images reveal significant morphological changes in the composite post-impregnation with rGO, which can facilitate greater attenuation of microwaves passing through the composite. Optical Microscope The optical microscopy analysis of untreated Moringa fiber in Fig. 4 (a) reveals an irregular and non-uniform surface texture, likely attributed to the presence of surface contaminants such as dirt, waxes, oils, residues from the plant's cellular structure, and other foreign particles. Bright patches observed on the fiber surface may result from prolonged exposure to sunlight and environmental factors during the plant's growth. Following alkali treatment, significant changes in the optical appearance of Moringa fiber are evident in Fig. 4 (b). The surface features appear cleaner, with enhanced visibility and longitudinal alignment of microfibrils. This improvement is attributed to the removal of non-cellulosic materials. However, dark spots observed on the treated fiber surface may indicate chemical modification or degradation of lignin, natural pigments, or impurities due to non-uniform treatment. Alkali treatment increases the porosity of the fiber surface, promoting scattering and multiple reflections of incident waves, thereby enhancing absorption efficiency. Figure 4 (c) displays rGO-coated post treated natural fiber, revealing a non-uniform distribution and modified texture of the fiber surface. Small irregular spots and flake-like patches may result from overlapping or agglomeration of rGO nanoparticles. In Fig. 4 (d), optical images of MOF/EPOX composite show no evidence of fibers due to a thick and opaque layer of epoxy. Additionally, the cracks, voids, and bubbles on the composite surface are possibly due to faulty curing processes. Figure 4 (e) depicts rGO/MOF/EPOX composite with well-distributed rGO and randomly aligned fibers. Dark spots on the surface indicate dense rGO agglomeration, while dot-like spots may signify the presence of rGO nanoparticles. Furthermore, the images illustrate the adhesion of fibers with epoxy, indicating effective load transfer leading to enhancement in mechanical features. Additionally, due to this adhesion, the interface between fibers and epoxy allows for multiple reflections and random scattering of incident microwaves, facilitating efficient absorption of energy within the composite. Water Absorption Test From the data presented in Fig. 5 (a) it is evident that alkali treatment of fibers results in a notable reduction in water absorption efficiency. This reduction can be attributed to the removal of hydrophilic components such as hemicellulose and lignin, as well as a decrease in voids and pores that tend to trap water. Furthermore, analysis of Fig. 5 (b) reveals a significant decrease in the water absorption efficiency of the MOF/EPOX composite following the induction of reduced graphene oxide (rGO). This reduction can be attributed to the inherently hydrophobic nature of rGO nanoparticles[ 23 ]. The hydrophobicity of rGO arises from its sp 2 -hybridized carbon atoms, which create a non-polar surface that repels polar water molecules. Additionally, the reduction of oxygen-containing functional groups, lowers surface energy of rGO, thereby minimizing its interactions with higher surface energy entities such as water. Hence, the effective dispersion of rGO enhances hydrophobic nature of overall composite. It is important to note that water, having a significantly higher dielectric constant compared to Moringa fiber and Epoxy, can substantially increase the overall permittivity of the composite. This increase in permittivity may correspond to greater dielectric loss due to the high degree of polarization and relaxation processes. Furthermore, water-filled voids within the composite may act as scattering centers, increasing the interaction time of microwaves and facilitating absorption through multiple scattering events. However, it is crucial to consider the potential drawbacks of water absorption in composites. Water absorption can lead to swelling, ultimately resulting in mechanical degradation of the epoxy matrix by weakening of the fiber-matrix interface. This degradation can compromise the overall structural durability of the composite. Additionally, prolonged exposure to water may lead to the oxidation of filler particles, potentially impacting the microwave absorption efficiency of the composite. In summary, the analysis of water absorption behavior is essential for the fabrication of optimized designs of fiber-epoxy-based composites for microwave absorption performance, particularly in applications involving humid and wet environments. Mechanical Property Vickers hardness testing can be applied to evaluate the hardness of the composite material. The hardness of composite material depends upon various factors such as properties of the constituent materials, their volume fractions, the nature of interfaces, and the microstructure of the composite. Depending upon the uniformity of alignment of fibers and reinforcing elements in the composite, the hardness values may also vary. From the Fig. 6 it can be observed that the hardness of MOF/EPOX and rGO/MOF/EPOX composites has increased by 14.72% and 22% respectively compared to pure epoxy composite. The enhancement in hardness can be attributed to the strong interfacial bonding between fiber and matrix which play an essential role in transferring load between the phases[ 23 ]. Strong interfacial bonding enhances stress transfer and helps distribute applied loads more evenly throughout the composite leading to higher hardness value. Moreover, the stiffness and rigidity of reinforced moringa fiber contributed to overall stiffness and rigidity. Further, addition of rGO into the composite has significant effect on increasing the hardness of the composite which can be attributed to enhance interfacial bonding due to proper dispersion of rGO in composite. This facilitates better stress distribution and increased resistance to indentation, contributing to higher hardness values. Thermal Analysis Thermal conductivity is a material property that quantifies a material's ability to conduct heat, determining how easily heat can pass through a material. In composite materials, thermal conductivity is influenced by the conductivities of the constituent materials, their volume fractions, and the nature of the interfaces. Heat in these materials is primarily carried by lattice vibrations known as phonons. In the Fig. 7 it can be observed that the thermal conductivity of MOF/EPOX and rGO/MOF/EPOX composite increases with increasing temperature, which can be explained by the Debye model of specific heat and thermal conductivity. At low temperatures, the phonon contribution to thermal conductivity increases as more phonon modes are excited. As temperature increases, phonon-phonon scattering becomes significant, affecting thermal conductivity. Furthermore, as shown in the Fig. 7 , the thermal conductivity of the rGO/MOF/EPOX composite is significantly higher compared to the MOF/EPOX composite. This enhancement in thermal conductivity can be attributed to the high thermal conductivity of rGO, due to its two-dimensional structure and strong sp 2 carbon-carbon bonds. Also the alignment of fibers within the composite has the potential to influence thermal conductivity. The presence of rGO in the composite provides highly efficient pathways for heat transfer and better phonon coupling by bridging the gaps between fibers and the matrix[ 23 ]. In composite materials, multiple interfaces can hinder heat transfer. However, the well-dispersed rGO nanopowder in the composite helps to reduce this interfacial thermal resistance, promoting effective heat transfer. As temperature rises, anharmonic effects become more pronounced, leading to increased phonon scattering. The higher population of phonons results in more frequent phonon-phonon scattering events, which hinder the flow of thermal energy, thereby reducing the mean free path of phonons and decreasing the thermal conductivity. Thermal conductivity play a crucial role in the performance and stability of microwave absorbing materials. By optimizing thermal conductivity, these materials can be fabricated to efficiently attenuate microwave energy while maintaining thermal stability and compatibility. Microwave absorption properties The gradual decrease in the dielectric constant for MOF/EPOX and rGO/ MOF/EPOX composite can be attributed to the material's microstructure and the interactions between the composite components[ 24 ]. When Moringa oleifera fibers added to the epoxy matrix the interfacial areas between the fibers and the matrix increases which causes polarization effects leading to decrease of overall dielectric constant as shown in Fig. 8 . At lower frequencies, different polarization mechanisms such as electronic, ionic, dipolar, and interfacial polarization contribute to the dielectric constant. As frequency increases, these polarization mechanisms cannot keep up with the rapidly changing electric field. Consequently, the contribution of these polarizations diminishes, leading to a decrease in the dielectric constant. At higher frequencies, the time available for dipole orientation is reduced, causing a lag in response[ 25 ]. This relaxation effect results in a lower dielectric constant at higher frequencies. The addition of rGO increases dielectric constant (ε’) at lower frequencies from 3.28 to 3.35 and at higher frequencies increase from 2.94 to 3.02 compared to MOF/EPOX composite. This may be attributed to rGO due to its high surface area and multiple conductive pathways, facilitating the accumulation and retention of electrical charges within the composite structure[ 25 ]. At higher frequencies, interfacial polarization effects become less significant because the dipoles at the interfaces cannot reorient quickly enough, leading to a reduction in the overall dielectric constant. In the X-band frequency range, the dielectric constant decreases because the material's response to the electric field is no longer in phase, resulting in reduced polarization efficiency and a lower dielectric constant. The dielectric loss (ε”) of MOF/EPOX and rGO/ MOF/EPOX composite increases gradually with increase of frequency as shown in Fig. 9 . This may be attributed due to enhanced surface roughness by the alkali treatment and introduces polar functional groups, leading to increased interfacial polarization and dielectric loss. Further, the incorporation of rGO enhances the conductivity of the composite, resulting in increased energy dissipation and dielectric loss[ 26 ]. Moreover, the synergistic effect between alkali-treated fibers and rGO promotes enhanced interfacial interactions, which contribute to the gradual rise in dielectric loss with increasing frequency in the X-band range. The increase in tangent loss with frequency in MOF/EPOX and rGO/ MOF/EPOX composites can be attributed to the microstructure and material properties of the composites as shown in Fig. 10 . At lower frequencies, the movement of molecules or particles within the composite material is relatively slow. This allows for better alignment and organization of the composite components, resulting in lower friction and energy dissipation at the interfaces between the epoxy matrixes, rGO coatings. However, as the frequency increases, the movement becomes more rapid, leading to increased friction and energy dissipation at these interfaces. Again, at higher frequencies, the polarization of molecules and dipoles may not be able to keep up with the rapidly changing electric field, leading to increased energy loss due to dielectric relaxation. As per Maxwell’s electromagnetic wave equation in an ionized medium[ 27 ] where ε* is complex permittivity and μ* is magnetic permeability of the medium of propagation, the propagation of electromagnetic waves in materials depends on their dielectric properties In heterogeneous materials like composites, variations in dielectric properties can lead to non-uniform electric field distributions, especially at interfaces between phases with different permittivity. This can cause local concentration of electric field lines, resulting in enhanced energy dissipation and increased tangent loss at higher frequencies. Further, dispersion mechanisms such as interfacial polarization, dipolar relaxation, and conductive losses can contribute to frequency-dependent tangent loss due to addition of rGO in composites, the conductivity of the rGO layers may lead to increased losses at higher frequencies due to eddy current losses and other conductivity-related mechanisms.The variation of reflection loss for MOF/EPOX and rGO/ MOF/EPOX composites with frequency shown in Fig. 11 can be explained based on Maxwell's wave propagation in dielectric media. Maxwell's equations in response to electric and magnetic fields interaction with matter, including dielectric materials like composites. The dielectric permittivity (ε*) of a material determines how much the material can polarize in response to an applied electric field. In composites, variations in permittivity arise from the different constituents (epoxy, Moringa oleifera fibers, and rGO coatings) and their spatial distribution. At lower frequencies, the wavelength of the incident electromagnetic wave is longer, and the polarization of the composite material can effectively follow the changing electric field. This results in lower reflection loss − 10.80dB for MOF/EPOX and − 13.86dB for rGO/ MOF/EPOX composite because the incident wave can penetrate deeper into the material before being reflected back. However, at higher frequencies, where the wavelength becomes comparable to or smaller than the dimensions of the composite constituents, the mismatch in permittivity at interfaces causes more significant reflection loss at frequency 11.812GHz are found to be -11.46dB and − 17.71dB for MOF/EPOX and rGO/ MOF/EPOX respectively due to high mismatch of impedance as observed in the present investigation. Again at lower frequencies, the penetration depth of the incident wave is larger, allowing for more opportunities for absorption and dissipation of energy within the material[ 28 ]. However, at higher frequencies, where the penetration depth decreases, multiple scattering events at interfaces become more significant, leading to increased reflection loss. Further, the formation of large no. of resonance cavities as observed in SEM images of the composite material lead to frequency-dependent reflection behavior. As the material has high reflection loss in MOF/EPOX and rGO/ MOF/EPOX composites it corresponds to microwave absorption efficiency increase from 92.06–98.42% which is due to impregnation of rGO in MOF/EPOX composite. Conclusion The study demonstrates the significant potential of Moringa Oleifera fiber (MOF) as a sustainable and effective reinforcement material for electromagnetic shielding applications. The incorporation of reduced graphene oxide (rGO) into the MOF/epoxy (EPOX) composite enhances both the electromagnetic shielding properties and the mechanical strength of the material. The comprehensive analysis, including morphological, structural, mechanical, thermal, and microwave absorption properties, confirms that the rGO/MOF/EPOX composite exhibits superior performance compared to traditional materials. The enhanced dielectric properties and increased absorption efficiency due to the addition of rGO, improves the complex permittivity and leads to a remarkable reflection loss. The SEM and optical microscopy analyses reveal a well-dispersed and uniform distribution of rGO, contributing to improved interfacial bonding and mechanical integrity. The water absorption tests indicate reduced hydrophobicity, enhancing the composite's durability in humid environments. Mechanical testing shows significant improvements in hardness and thermal conductivity, indicating that the composite can withstand various operational conditions. The dielectric constant and loss tangent analyses illustrate the composite's ability to interact efficiently with electromagnetic waves, leading to effective shielding performance. The reflection loss measurements confirm the composite's capability to minimize electromagnetic interference effectively. Overall, the rGO/MOF/EPOX composite emerges as a promising candidate for electromagnetic shielding applications, offering a sustainable, lightweight, and high-performance alternative to conventional materials. The study establishes that rGO/MOF/EPOX composites exhibit an enhancement of microwave absorption efficiency of 92.06–98.42% in the X-band frequency range making them a sustainable and effective alternative for advanced EM shielding materials. Further, this study not only contributes to the development of advanced composite materials but also paves the way for the utilization of waste materials in high-tech applications, aligning with the principles of sustainability and eco-friendliness. Future research could further optimize the composite's properties and explore its potential in various industrial applications, addressing the growing concerns of electronic pollution and electromagnetic interference. Declarations Competing Interests The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence this paper. Competing interests The authors have no financial or non-financial interests to disclose. Funding The research was a part of academic programme. The authors declare that no funds, grant or other support were received during the preparation of this manuscript or study. Author Contributions All the authors contributed equally in the experimental design, analysis and preparation of manuscript. Acknowledgement The authors are grateful to the Science and Technology Department, Govt. of Odisha for sanctioning the Project No.3692 /ST and Vice-Chancellor of the Veer Surendra Sai University of Technology, Burla, for laboratory facilities to execute the project Data Availability Enquiries about data availability should be directed to the authors. References Zhang, Q., Liang, Q., Zhang, Z., Kang, Z., Liao, Q., Ding, Y., Ma, M., Gao, F., Zhao, X., Zhang, Y.: Electromagnetic Shielding Hybrid Nanogenerator for Health Monitoring and Protection. Adv. Funct. Mater. 28, (2018). https://doi.org/10.1002/adfm.201703801 Zhang, X., Wei, W., Zhang, S., Wen, B., Su, Z.: Advanced 3D nanohybrid foam based on graphene oxide: Facile fabrication strategy, interfacial synergetic mechanism, and excellent photocatalytic performance. Sci. 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Forum. 869, 283–287 (2016). https://doi.org/10.4028/www.scientific.net/MSF.869.283 Marya Raji, Souad Nekhlaoui, Charles Amani Kakou, Hamid Essabir, Rachid Bouhfid, A. el kacem Q.: Chapter 9 - Thermal properties of coir fiber-reinforced polymer composites. In: Coir Fiber and its Composites. pp. 191–220 (2022) Malkapuram, B.G.| C.V.| R.: Investigation on Mechanical, Thermal and Water Absorption Properties of Banana/Coir Reinforced Polypropylene Hybrid Composites. J. Compos. Adv. Mater. 123–131 (2020). https://doi.org/https://doi.org/10.18280/rcma.303-402 G.L. Devnani, S.S., More, S.: Extraction, characterization and thermal degradation kinetics with activation energy of untreated and alkali treated Saccharum spontaneum (Kans grass) fiber. Compos. Part B Eng. 166, 436–445 (2019). https://doi.org/https://doi.org/10.1016/j.compositesb.2019.02.042 Hong He, Fengping An, Yiwei Wang, Wanying Wu, Zhiwei Huang, H.S.: Effects of pretreatment, NaOH concentration, and extraction temperature on the cellulose from Lophatherum gracile Brongn. Int. J. Biol. Macromol. Support. open access. 190, 810–818 (2021). https://doi.org/https://doi.org/10.1016/j.ijbiomac.2021.09.041 A. Ivanovska, D. Cerovic, N. Tadic, I. Jankovic Castvan, K. Asanovic, M.K.: Sorption and dielectric properties of jute woven fabrics: Effect of chemical composition. Ind. Crops Prod. 140, 111632 (2019). https://doi.org/International Journal of Biological Macromolecules Supports open access Biao Zhao, Chao Ma, Luyang Liang, Wenhui Guo, Bingbing Fan, X.G. and R.Z.: An impedance match method used to tune the electromagnetic wave absorption properties of hierarchical ZnO assembled by porous nanosheets. 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Brewer, D.S.T.& Z.-Y.C.: Process and Microstructure to Achieve Ultra-high Dielectric Constant in Ceramic-Polymer Composites. Sci. Rep. 6, 35763 (2016). https://doi.org/https://doi.org/10.1038/srep35763 Dissado, L.A., Hill, R.M.: Dielectric behaviour of materials undergoing dipole alignment transitions. Philos. Mag. B. 41, 625–642 (1980). https://doi.org/10.1080/13642818008245413 Wang, Y., Guan, H., Dong, C., Xiao, X., Du, S., Wang, Y.: Reduced graphene oxide (RGO)/Mn3O4 nanocomposites for dielectric loss properties and electromagnetic interference shielding effectiveness at high frequency. Ceram. Int. 42, 936–942 (2016). https://doi.org/10.1016/j.ceramint.2015.09.022 Tip, A.: Some mathematical properties of Maxwell’s equations for macroscopic dielectrics. J. Math. Phys. 47, (2006). https://doi.org/10.1063/1.2158432 Elmahaishi, M.F., Azis, R.S., Ismail, I., Muhammad, F.D.: A review on electromagnetic microwave absorption properties: their materials and performance. J. Mater. Res. Technol. 20, 2188–2220 (2022). https://doi.org/10.1016/j.jmrt.2022.07.140 Supplementary Files Highlights.docx Graphicalabstract.docx Cite Share Download PDF Status: Published Journal Publication published 17 Nov, 2024 Read the published version in Waste and Biomass Valorization → Version 1 posted Reviewers agreed at journal 29 Jul, 2024 Reviewers invited by journal 28 Jul, 2024 Editor invited by journal 12 Jun, 2024 Editor assigned by journal 28 May, 2024 First submitted to journal 27 May, 2024 You are reading this latest preprint version Research Square lets you share your work early, gain feedback from the community, and start making changes to your manuscript prior to peer review in a journal. As a division of Research Square Company, we’re committed to making research communication faster, fairer, and more useful. We do this by developing innovative software and high quality services for the global research community. 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Also discoverable on Platform About Our Team In Review Editorial Policies Advisory Board Help Center Resources Author Services Accessibility API Access RSS feed Manage Cookie Preferences © Research Square 2026 | ISSN 2693-5015 (online) Privacy Policy Terms of Service Do Not Sell My Personal Information {"props":{"pageProps":{"initialData":{"identity":"rs-4485842","acceptedTermsAndConditions":true,"allowDirectSubmit":false,"archivedVersions":[],"articleType":"Research Article","associatedPublications":[],"authors":[{"id":332750776,"identity":"893e1b98-05b8-428a-a9f5-63d17eac5fb4","order_by":0,"name":"Ganeswar Nath","email":"data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAZAAAAAyAQMAAABI0h/eAAAABlBMVEX///8AAABVwtN+AAAACXBIWXMAAA7EAAAOxAGVKw4bAAAA9klEQVRIiWNgGAWjYLADZoYKEMncQLQOxmaGMyAtjKRoYWwD0/i1yLufPfjwZ5tdPoN08/PHhfNqo/nbgVp+VGzDqcXwTF6yMW9bsmWDzDHD5pnbjufOOMzYwNhz5jZuLQ05ZtKM25gNGCQSDJt5tx3LbQBqYWZsw6Ol/435z5/b6oFa0j828845ljufkBZ5iRwzBt5th4FacoC2NNTkbiCkxUDijbE077/jBmwSOYWzeY4dyN0I1HIQn1/k+3MMP/44U23AL5G+4TNPTV3uvPOHDz74UYHHlgNQBhuEOgwmD2BTCrelAZVfh0/xKBgFo2AUjFAAAFRQWFXqgYDNAAAAAElFTkSuQmCC","orcid":"","institution":"Veer Surendra Sai University of Technology","correspondingAuthor":true,"prefix":"","firstName":"Ganeswar","middleName":"","lastName":"Nath","suffix":""},{"id":332750777,"identity":"427db136-9b95-4af2-bec3-027e2a7bee31","order_by":1,"name":"Biswabandita Samantara","email":"","orcid":"","institution":"Veer Surendra Sai University of 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1","display":"","copyAsset":false,"role":"figure","size":894109,"visible":true,"origin":"","legend":"\u003cp\u003eMaterial fabrication Process\u003c/p\u003e","description":"","filename":"1.png","url":"https://assets-eu.researchsquare.com/files/rs-4485842/v1/46111ffec3287da86a7b2280.png"},{"id":63115778,"identity":"d36219a7-2a82-4411-ae74-f2e8b4650a11","added_by":"auto","created_at":"2024-08-23 09:49:46","extension":"png","order_by":2,"title":"Figure 2","display":"","copyAsset":false,"role":"figure","size":51903,"visible":true,"origin":"","legend":"\u003cp\u003eFTIR spectra for Moringa Oleifera Fiber\u003c/p\u003e","description":"","filename":"2.png","url":"https://assets-eu.researchsquare.com/files/rs-4485842/v1/61fb4298d102c5c072d81865.png"},{"id":63116373,"identity":"edef151f-3ca3-481c-9b75-6c983ca7f4a9","added_by":"auto","created_at":"2024-08-23 09:57:46","extension":"png","order_by":3,"title":"Figure 3","display":"","copyAsset":false,"role":"figure","size":725670,"visible":true,"origin":"","legend":"\u003cp\u003eSEM image of (a, b) MOF/EPOX (c) rGO/MOF/EPOX\u003c/p\u003e","description":"","filename":"3.png","url":"https://assets-eu.researchsquare.com/files/rs-4485842/v1/a68a69b735df0a35bee41e1f.png"},{"id":63116820,"identity":"155a6276-8a4e-4869-8754-882668c59b49","added_by":"auto","created_at":"2024-08-23 10:05:46","extension":"png","order_by":4,"title":"Figure 4","display":"","copyAsset":false,"role":"figure","size":2283247,"visible":true,"origin":"","legend":"\u003cp\u003eOptical Microscopy Images of (a) Untreated Moringa Fiber (b) Treated Moringa Fiber(c) rGO coated Moringa Fiber (d) MOF/EPOX composite (e) rGO/MOF/EPOX Composite\u003c/p\u003e","description":"","filename":"4.png","url":"https://assets-eu.researchsquare.com/files/rs-4485842/v1/88d3a4d3acfa4aa8aacbaeea.png"},{"id":63115787,"identity":"d8db8363-2b12-4d19-bdcd-dd26fb84b23c","added_by":"auto","created_at":"2024-08-23 09:49:47","extension":"png","order_by":5,"title":"Figure 5","display":"","copyAsset":false,"role":"figure","size":40653,"visible":true,"origin":"","legend":"\u003cp\u003eWater absorption plot for (a) Untreated MOF, Alkali treated MOF (b) MOF/EPOX composite and rGO/MOF/EPOX composite\u003c/p\u003e","description":"","filename":"5.png","url":"https://assets-eu.researchsquare.com/files/rs-4485842/v1/01f69bdd57e5333e3b84f64a.png"},{"id":63115783,"identity":"7dc75286-7670-4d83-9f99-32d5d16200f0","added_by":"auto","created_at":"2024-08-23 09:49:46","extension":"png","order_by":6,"title":"Figure 6","display":"","copyAsset":false,"role":"figure","size":57555,"visible":true,"origin":"","legend":"\u003cp\u003eVickers hardness result for Epoxy, MOF/EPOX and rGO/MOF/EPOX composite\u003c/p\u003e","description":"","filename":"6.png","url":"https://assets-eu.researchsquare.com/files/rs-4485842/v1/c2e10c47ec6ae685d978d39f.png"},{"id":63115777,"identity":"62b43941-9608-4180-9ddc-0ed03880e1cd","added_by":"auto","created_at":"2024-08-23 09:49:46","extension":"png","order_by":7,"title":"Figure 7","display":"","copyAsset":false,"role":"figure","size":40201,"visible":true,"origin":"","legend":"\u003cp\u003eThermal conductivity plot for Epoxy, MOF/EPOX, rGO/MOF/EPOX composite\u003c/p\u003e","description":"","filename":"7.png","url":"https://assets-eu.researchsquare.com/files/rs-4485842/v1/49903575ad49b6faeb108c3f.png"},{"id":63115788,"identity":"b15aa938-5728-4f63-ab8c-4b0d44d82acf","added_by":"auto","created_at":"2024-08-23 09:49:47","extension":"png","order_by":8,"title":"Figure 8","display":"","copyAsset":false,"role":"figure","size":35690,"visible":true,"origin":"","legend":"\u003cp\u003eDielectric constant plot for MOF/EPOX and rGO/MOF/EPOX composite\u003c/p\u003e","description":"","filename":"8.png","url":"https://assets-eu.researchsquare.com/files/rs-4485842/v1/44bb564d51486892064c9b3d.png"},{"id":63115779,"identity":"88628dfd-3bb2-41fb-9694-dcaf4bd8838d","added_by":"auto","created_at":"2024-08-23 09:49:46","extension":"png","order_by":9,"title":"Figure 9","display":"","copyAsset":false,"role":"figure","size":31520,"visible":true,"origin":"","legend":"\u003cp\u003eDielectric loss plot for MOF/EPOX and rGO/MOF/EPOX composite\u003c/p\u003e","description":"","filename":"9.png","url":"https://assets-eu.researchsquare.com/files/rs-4485842/v1/4048c40814c83bc49052b540.png"},{"id":63116372,"identity":"ab7139a8-6a76-4463-9fb0-5ca2f919b4c5","added_by":"auto","created_at":"2024-08-23 09:57:46","extension":"png","order_by":10,"title":"Figure 10","display":"","copyAsset":false,"role":"figure","size":35611,"visible":true,"origin":"","legend":"\u003cp\u003eTangent loss plot for MOF/EPOX and rGO/MOF/EPOX composite\u003c/p\u003e","description":"","filename":"10.png","url":"https://assets-eu.researchsquare.com/files/rs-4485842/v1/918b258db12660146b3a705d.png"},{"id":63115784,"identity":"1ebd1219-ce09-412e-85d0-d644122bf1de","added_by":"auto","created_at":"2024-08-23 09:49:46","extension":"png","order_by":11,"title":"Figure 11","display":"","copyAsset":false,"role":"figure","size":33477,"visible":true,"origin":"","legend":"\u003cp\u003eReflection loss plot for MOF/EPOX and rGO/MOF/EPOX composite\u003c/p\u003e","description":"","filename":"11.png","url":"https://assets-eu.researchsquare.com/files/rs-4485842/v1/c4f43322a73529e96e6470bc.png"},{"id":69286022,"identity":"39dbe325-d246-4e09-a8d1-3d9b308d5ced","added_by":"auto","created_at":"2024-11-18 19:29:03","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":5838051,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-4485842/v1/eb3fa52c-a453-408d-932b-857c5ef72ed1.pdf"},{"id":63115776,"identity":"629af545-274d-4039-8d9a-38974873aff5","added_by":"auto","created_at":"2024-08-23 09:49:46","extension":"docx","order_by":1,"title":"","display":"","copyAsset":false,"role":"supplement","size":13932,"visible":true,"origin":"","legend":"","description":"","filename":"Highlights.docx","url":"https://assets-eu.researchsquare.com/files/rs-4485842/v1/5bda10f5e2a9f57aedee85b1.docx"},{"id":63115781,"identity":"c21f3ec0-719b-4977-b227-15dbd199b8f2","added_by":"auto","created_at":"2024-08-23 09:49:46","extension":"docx","order_by":2,"title":"","display":"","copyAsset":false,"role":"supplement","size":3526862,"visible":true,"origin":"","legend":"","description":"","filename":"Graphicalabstract.docx","url":"https://assets-eu.researchsquare.com/files/rs-4485842/v1/7f7c1b5db662ebdc547e2ece.docx"}],"financialInterests":"","formattedTitle":"Reduced GO decorated waste Moringa oleifera fiber composite for sustainable electromagnetic shielding material","fulltext":[{"header":"Statement of Novelty","content":"\u003cp\u003eRGO/MOF/EPOX composite a novel and versatile solution for electromagnetic absorption, combining the benefits of natural fiber reinforcement, synergistic electromagnetic properties, biodegradability, and cost-effectiveness. The highly conductive nature of rGO, coupled with the dielectric properties of MO fiber, enhances the absorption of electromagnetic waves across a wide frequency range. This synergistic interaction results in improved absorption performance compared to composites containing only one of these components.\u003c/p\u003e"},{"header":"Introduction","content":"\u003cp\u003eThe evolution of internet of things (IoT) based electronic gadgets and its implementation in everyday life as well as in high security places generates the complex electronic pollution in the open environment. The issue of electronic pollution now a day\u0026rsquo;s plays major role in the technology system as well as human health. Consequently, there are growing concerns about the potential for 5G signals to interfere with existing communication systems, such as radio, television, and satellite transmissions, in defense system as well as with biological organisms and ecosystems. This introduction sets the stage for a deeper exploration of the potential environmental impacts of 5G networks and the need for effective mitigation strategies to address electromagnetic interference/pollution[\u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e, \u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e].The selection of electromagnetic (EM) shielding material is crucial, with an emphasis on compactness, lightweight, ease of manufacture, and sustainability over reflective types. As EM shielding materials are essential across diverse industries, ensuring proper functionality and reliability of electronic devices their manufacturing process meets the challenges for its effectiveness for which it depends on the composition of material along with its sustainability and eco-friendliness with environment[\u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e3\u003c/span\u003e, \u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e4\u003c/span\u003e].Challenges linked to conventional ferrite electromagnetic absorbers include limitations in frequency range effectiveness, bulkiness, and weight. Traditional ferrite materials are often most effective within specific frequency bands, limiting their versatility across a broader spectrum. Additionally, their inherent bulk and weight can pose practical challenges, especially in applications requiring lightweight and compact solutions. Moreover, traditional ferrite absorbers may exhibit performance degradation under extreme environmental conditions, such as high temperatures or mechanical stress, impacting their reliability and durability. These issues highlight the need for alternative materials and designs to overcome the limitations associated with traditional ferrite electromagnetic absorbers. Natural fibers offer several advantages that can address the challenges posed by conventional ferrite electromagnetic absorbers. By carefully selecting and processing natural fibers, it's possible to create composites that exhibit absorption across a wider spectrum of frequencies, increasing their versatility and applicability in various electromagnetic shielding applications. Furthermore, natural fibers can be combined with other materials, such as conductive coatings or nanoparticles, to enhance their electromagnetic absorption properties further. This approach allows for the customization of natural fiber-based composites to meet specific performance requirements and overcome the limitations of traditional ferrite absorbers. In the present work MOF waste contributes a unique combination of structural features that render them highly valuable as reinforcements in various applications. Drumstick fibers possess a distinctive set of structural attributes that make them particularly well-suited for applications requiring microwave absorption. Their high aspect ratio and fibrillar microstructure facilitate efficient interaction with electromagnetic waves, enhancing absorption capabilities. Additionally, the cellulose composition and natural lignin content contribute to the dielectric properties of drumstick fibers, optimizing their ability to dissipate microwave energy. The porous structure further aids in the absorption process by promoting multiple reflections and attenuating microwave signals. Furthermore, the flexibility and uniformity of drumstick fibers allow for their incorporation into microwave-absorbing materials without compromising mechanical integrity, ensuring consistent performance across different frequencies and environmental conditions. Incorporating reduced graphene oxide (rGO) into natural fiber-based composites has sparked innovation in functional material development has wide range of applications. Its lightweight nature, cost-effectiveness, and high performance make it attractive filler for advanced composites. By introducing rGO to carbonaceous materials, the molecular and structural composition undergoes modification, resulting in improved abilities to capture electromagnetic waves (EMW) through various mechanisms and interfacial polarizations which leads to exceptional electromagnetic shielding performance[\u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e4\u003c/span\u003e].The compatibility between reduced graphene oxide (rGO) and drumstick fiber lies in their complementary properties and potential synergies[\u003cspan additionalcitationids=\"CR6\" citationid=\"CR5\" class=\"CitationRef\"\u003e5\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR7\" class=\"CitationRef\"\u003e7\u003c/span\u003e]. Drumstick fibers offer mechanical reinforcement and dielectric properties, while rGO contributes high electrical conductivity and a large surface area. The work ensemble have well studied the electromagnetic shielding performance of MOF with incorporation of rGO through analysis of different parameter like complex permittivity, loss tangent, reflection loss. Further, to support the microwave characteristics, the mechanical property like hardness and physical properties such as thermal conductivity and moisture absorption of the raw material as well as composite has been ornamented. There is no such work is reported till today on the waste material of MOF which has been taken in the present context as reinforced material for composite with rGO, except some work on mechanical property and its food value has been studied by some authors[\u003cspan additionalcitationids=\"CR9 CR10 CR11 CR12\" citationid=\"CR8\" class=\"CitationRef\"\u003e8\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR13\" class=\"CitationRef\"\u003e13\u003c/span\u003e].Thus the present work may provide be an alternative potential candidate for electromagnetic shielding application in design of stealth material.\u003c/p\u003e"},{"header":"Material and methodology","content":"\u003cdiv id=\"Sec3\" class=\"Section2\"\u003e \u003ch2\u003eMaterials for fabrication\u003c/h2\u003e \u003cp\u003eDrumstick fiber composites were prepared by collecting waste drumstick raw materials from local areas. Reduced Graphene Oxide (rGO) from SHILPENT enterprises, boasting a purity level exceeding 98%, was used as a coating filler material. The rGO had varying diameters between 10 to 15 \u0026micro;m and thickness ranging from 10 to 15 nm. Sodium hydroxide (NaOH) was employed as a surfactant for surface treatment of the raw fibers. Epoxy-LY556 and Hardener-HY951, mixed at a ratio of 10:1, served as the matrix and binding agent for the fibers. A pure aluminum mold (Jindal-344, 15 cm \u0026times; 15 cm \u0026times; 1 cm) was utilized for fabricating bulk drumstick fiber composites, with specific dimensions (23 mm \u0026times; 11 mm \u0026times; 3 mm) for the X-Band sample[\u003cspan citationid=\"CR14\" class=\"CitationRef\"\u003e14\u003c/span\u003e]. 1 mm thick teflon sheet was used to cover the mold to facilitate easy removal of the composite, while silicon oil spray was applied to coat the molding area.\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec4\" class=\"Section2\"\u003e \u003ch2\u003eSurface treatment and coating of rGO on raw MO fiber\u003c/h2\u003e \u003cp\u003eThe collected raw drumstick fibers were thoroughly splashed with running water to eliminate debris. The washed drumstick fibers were placed in sunlight for a week to enhance the smooth extraction of raw fibers. Then, the fibers were seized into approximately 5\u0026ndash;10 cm in length followed by a combing process. The raw combined fibers were immersed in a beaker containing alkaline solution prepared by dissolving NaOH pallets in distilled water under sonication operated at frequency of 125 KHz and 60W power. The treated fibers were further cleaned with distilled water to remove the deposition of NaOH solution from the surface of the fiber if any. This cleaning changes the surface color of the fiber with enhanced surface area of the fiber modifying the surface become highly rough for better binding of fibers with matrix. With the help of a mechanical stirrer the coating of drumstick fiber with industrial graded rGO has been performed. The mechanical stirrer was operated with 600rpm for 30 minutes to disperse the rGO powder uniformly over the drumstick fiber. Finally, a mixture of resin and hardener, at a ratio of 10:1, was combined with the 10% volume fraction of fibers containing 1wt% rGO. The stirring speed was reduced to 100rpm to prevent the formation of gas bubbles until a homogeneous liquid mixture was achieved within which the treated drumstick fibers were well impregnated by rGO within the mixture. The details fabrication process for composite has been shown in Fig.\u0026nbsp;\u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e1\u003c/span\u003e.\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec5\" class=\"Section2\"\u003e \u003ch2\u003eCharacterization and experimental measurement\u003c/h2\u003e \u003cp\u003eTo characterize MOF for their potential use in microwave absorption, several analytical techniques are employed. The morphological changes in the rGO added composite and their composition are investigated by utilizing HITACHI, FLEX SEM, 1000II to perform SEM. The porous structure, surface roughness, fiber orientation, and rGO aggregation on the fiber surface are all revealed by the SEM investigation of the composite. The compositional changes occurred in the MOF before and after the treatment has been well studied with the analysis of FTIR spectroscopic studies. To find out more about the microstructure of these anisotropic and heterogeneous materials, LEICA make optical microscopy is used. The fibrous nature of MOF and their rGO-coated composites has been performed to exactly know the extent of hydrophilicity for moisture resistance, performance of material under humid or wet conditions, for predicting the durability and longevity ,effect of RGO coating on improvement in moisture resistance due to the RGO layer, to predict and optimize the performance of the materials in microwave absorption applications, in electronic and electromagnetic applications, low water absorption is preferred to prevent degradation of properties has been investigated through water absorption test as per the ASTM-D5529 standard. In mechanical characterization, roughness and hardness test of the material has been performed. The Vickers hardness test, following the ASTM E384 standard, employs a 136\u0026deg; pyramidal diamond indenter to create a square-shaped indentation. A load is applied for 10 seconds, after which the two diagonals of the diamond-shaped indentation are measured in millimeters. The average of these measurements, denoted as dimension \u0026#119889;, is used to determine the hardness value.\u003c/p\u003e \u003c/div\u003e"},{"header":"Result and Discussion","content":"\u003cdiv id=\"Sec7\" class=\"Section2\"\u003e\n \u003ch2\u003eFTIR Analysis\u003c/h2\u003e\n \u003cp\u003eNoticeable changes in the intensity and position of the peaks, reflecting the chemical changes due to NaOH treatment of Moringa fiber as shown in Fig. \u003cspan class=\"InternalRef\"\u003e2\u003c/span\u003e. Broad Peak around 3400 cm⁻\u0026sup1; may corresponds to O-H stretching vibrations[\u003cspan class=\"CitationRef\"\u003e15\u003c/span\u003e]. NaOH treated fiber shows a shift or change in intensity, indicating alteration in hydroxyl groups.\u003c/p\u003e\n \u003cp\u003ePeaks around 2900 cm⁻\u0026sup1; may associated with C-H stretching vibrations[\u003cspan class=\"CitationRef\"\u003e15\u003c/span\u003e]. Changes in these peaks after treatment suggest modifications in the aliphatic content of the fibers. Peak around 1600 cm⁻\u0026sup1; to 1500 cm⁻\u0026sup1; may related to aromatic C\u0026thinsp;=\u0026thinsp;C stretching[\u003cspan class=\"CitationRef\"\u003e15\u003c/span\u003e]. Alterations in this region can indicate changes in the aromatic content or structure of lignin. Peaks in the 1300\u0026thinsp;\u0026minus;\u0026thinsp;1000 cm⁻\u0026sup1; range represent C-O stretching and C-H bending[\u003cspan class=\"CitationRef\"\u003e16\u003c/span\u003e, \u003cspan class=\"CitationRef\"\u003e17\u003c/span\u003e]. Changes in this region for NaOH treated fiber indicate modifications in cellulose and hemicellulose structures. Changes in the peak intensity around 1021 cm⁻\u0026sup1; after NaOH treatment suggest alterations in the fiber\u0026apos;s polysaccharide content[\u003cspan class=\"CitationRef\"\u003e18\u003c/span\u003e]. NaOH treatment typically results in the removal of hemicellulose and partial removal of lignin, leading to an increase in the relative content of cellulose. This is reflected in the FTIR spectrum as changes in the C-O stretching region. NaOH treatment typically removes hemicellulose, lignin, and other extractives, leading to an increase in cellulose content and alteration in functional groups, as evidenced by the changes in peak positions and intensities[\u003cspan class=\"CitationRef\"\u003e19\u003c/span\u003e]. The removal of hemicellulose and lignin increases the porosity and surface area of the fibers. Additionally, the increase in the relative cellulose content, lead to more ordered crystalline structure. This increased surface area and reduction in lignin content leads to enhance dielectric properties for better interaction with microwave radiation, leading to improved absorption capabilities[\u003cspan class=\"CitationRef\"\u003e20\u003c/span\u003e].\u003c/p\u003e\n\u003c/div\u003e\n\u003cdiv id=\"Sec8\" class=\"Section2\"\u003e\n \u003ch2\u003eStructural \u0026amp; Morphological Analysis\u003c/h2\u003e\n \u003cdiv class=\"BlockQuote\"\u003e\n \u003cp\u003eThe SEM images of the MOF/EPOX composite demonstrate a well-mixed and uniformly distributed epoxy resin across the fiber surfaces. The smooth dispersion of epoxy on the fiber surfaces, with no visible voids at the interfaces, indicates strong adhesion between the fiber and matrix, which is crucial for effective load transfer. Figure \u003cspan class=\"InternalRef\"\u003e3\u003c/span\u003e(a) and Fig. \u003cspan class=\"InternalRef\"\u003e3\u003c/span\u003e(b) show the random orientation of fibers within the composite, which may contribute to non-uniform mechanical properties. The epoxy matrix appears in continuous phase with minimal voids or air gaps. The presence of these voids in the matrix can influence the electric field behavior and polarization effects within the composite. These voids can lead to multiple scattering of microwaves, increasing the path length of incident waves and promoting more absorption. Additionally, the presence of air in these voids can enhance impedance matching, leading to better absorption[\u003cspan class=\"CitationRef\"\u003e21\u003c/span\u003e]. However, the presence of voids can also compromise the mechanical strength of the composite, making controlled distribution of voids crucial during fabrication. In some areas of the composite, epoxy-fiber fractures with rough surfaces are observed[\u003cspan class=\"CitationRef\"\u003e21\u003c/span\u003e, \u003cspan class=\"CitationRef\"\u003e22\u003c/span\u003e]. These fractures increase the irregular surface area and create air gaps, contributing to dielectric loss mechanisms due to the interaction of incident microwaves with the discontinuities, resulting in more random scattering and absorption.\u003c/p\u003e\n \u003c/div\u003e\n \u003cp\u003eFigure \u003cspan class=\"InternalRef\"\u003e3\u003c/span\u003e(c) shows the SEM image of an rGO-reinforced MOF/EPOX composite. The well-dispersed rGO at the fiber-matrix interface facilitates improved interfacial bonding, leading to effective load transfer. The uniform distribution of rGO across the fiber surfaces is critical for enhancing the mechanical properties of the composite material. The well-dispersed and firmly adhered rGO particles to the fiber surface could be a result of sonication processes during impregnation. The incorporation of rGO into the composite forms more effective network of conductive pathways and creates additional interfacial regions, enhancing the dielectric properties and contributing to improved conductive loss. The SEM images reveal significant morphological changes in the composite post-impregnation with rGO, which can facilitate greater attenuation of microwaves passing through the composite.\u003c/p\u003e\n\u003c/div\u003e\n\u003cdiv id=\"Sec9\" class=\"Section2\"\u003e\n \u003ch2\u003eOptical Microscope\u003c/h2\u003e\n \u003cp\u003eThe optical microscopy analysis of untreated Moringa fiber in Fig. \u003cspan class=\"InternalRef\"\u003e4\u003c/span\u003e(a) reveals an irregular and non-uniform surface texture, likely attributed to the presence of surface contaminants such as dirt, waxes, oils, residues from the plant\u0026apos;s cellular structure, and other foreign particles. Bright patches observed on the fiber surface may result from prolonged exposure to sunlight and environmental factors during the plant\u0026apos;s growth. Following alkali treatment, significant changes in the optical appearance of Moringa fiber are evident in Fig. \u003cspan class=\"InternalRef\"\u003e4\u003c/span\u003e(b).\u003c/p\u003e\n \u003cdiv class=\"BlockQuote\"\u003e\n \u003cp\u003eThe surface features appear cleaner, with enhanced visibility and longitudinal alignment of microfibrils. This improvement is attributed to the removal of non-cellulosic materials. However, dark spots observed on the treated fiber surface may indicate chemical modification or degradation of lignin, natural pigments, or impurities due to non-uniform treatment. Alkali treatment increases the porosity of the fiber surface, promoting scattering and multiple reflections of incident waves, thereby enhancing absorption efficiency. Figure \u003cspan class=\"InternalRef\"\u003e4\u003c/span\u003e(c) displays rGO-coated post treated natural fiber, revealing a non-uniform distribution and modified texture of the fiber surface. Small irregular spots and flake-like patches may result from overlapping or agglomeration of rGO nanoparticles. In Fig. \u003cspan class=\"InternalRef\"\u003e4\u003c/span\u003e(d), optical images of MOF/EPOX composite show no evidence of fibers due to a thick and opaque layer of epoxy. Additionally, the cracks, voids, and bubbles on the composite surface are possibly due to faulty curing processes. Figure \u003cspan class=\"InternalRef\"\u003e4\u003c/span\u003e(e) depicts rGO/MOF/EPOX composite with well-distributed rGO and randomly aligned fibers. Dark spots on the surface indicate dense rGO agglomeration, while dot-like spots may signify the presence of rGO nanoparticles. Furthermore, the images illustrate the adhesion of fibers with epoxy, indicating effective load transfer leading to enhancement in mechanical features. Additionally, due to this adhesion, the interface between fibers and epoxy allows for multiple reflections and random scattering of incident microwaves, facilitating efficient absorption of energy within the composite.\u003c/p\u003e\n \u003c/div\u003e\n\u003c/div\u003e\n\u003cdiv id=\"Sec10\" class=\"Section2\"\u003e\n \u003ch2\u003eWater Absorption Test\u003c/h2\u003e\n \u003cdiv class=\"BlockQuote\"\u003e\n \u003cp\u003eFrom the data presented in Fig. \u003cspan class=\"InternalRef\"\u003e5\u003c/span\u003e(a) it is evident that alkali treatment of fibers results in a notable reduction in water absorption efficiency. This reduction can be attributed to the removal of hydrophilic components such as hemicellulose and lignin, as well as a decrease in voids and pores that tend to trap water. Furthermore, analysis of Fig. \u003cspan class=\"InternalRef\"\u003e5\u003c/span\u003e(b) reveals a significant decrease in the water absorption efficiency of the MOF/EPOX composite following the induction of reduced graphene oxide (rGO). This reduction can be attributed to the inherently hydrophobic nature of rGO nanoparticles[\u003cspan class=\"CitationRef\"\u003e23\u003c/span\u003e]. The hydrophobicity of rGO arises from its sp\u003csup\u003e2\u003c/sup\u003e-hybridized carbon atoms, which create a non-polar surface that repels polar water molecules. Additionally, the reduction of oxygen-containing functional groups, lowers surface energy of rGO, thereby minimizing its interactions with higher surface energy entities such as water. Hence, the effective dispersion of rGO enhances hydrophobic nature of overall composite. It is important to note that water, having a significantly higher dielectric constant compared to Moringa fiber and Epoxy, can substantially increase the overall permittivity of the composite. This increase in permittivity may correspond to greater dielectric loss due to the high degree of polarization and relaxation processes.\u003c/p\u003e\n \u003c/div\u003e\n \u003cdiv class=\"BlockQuote\"\u003e\n \u003cp\u003eFurthermore, water-filled voids within the composite may act as scattering centers, increasing the interaction time of\u003c/p\u003e\n \u003cp\u003emicrowaves and facilitating absorption through multiple scattering events. However, it is crucial to consider the potential drawbacks of water absorption in composites. Water absorption can lead to swelling, ultimately resulting in mechanical degradation of the epoxy matrix by weakening of the fiber-matrix interface. This degradation can compromise the overall structural durability of the composite. Additionally, prolonged exposure to water may lead to the oxidation of filler particles, potentially impacting the microwave absorption efficiency of the composite. In summary, the analysis of water absorption behavior is essential for the fabrication of optimized designs of fiber-epoxy-based composites for microwave absorption performance, particularly in applications involving humid and wet environments.\u003c/p\u003e\n \u003c/div\u003e\n\u003c/div\u003e\n\u003cdiv id=\"Sec11\" class=\"Section2\"\u003e\n \u003ch2\u003eMechanical Property\u003c/h2\u003e\n \u003cdiv class=\"BlockQuote\"\u003e\n \u003cp\u003eVickers hardness testing can be applied to evaluate the hardness of the composite material. The hardness of composite material depends upon various factors such as properties of the constituent materials, their volume fractions, the nature of interfaces, and the microstructure of the composite. Depending upon the uniformity of alignment of fibers and reinforcing elements in the composite, the hardness values may also vary. From the Fig. \u003cspan class=\"InternalRef\"\u003e6\u003c/span\u003e it can be observed that the hardness of MOF/EPOX and rGO/MOF/EPOX composites has increased by 14.72% and 22% respectively compared to pure epoxy composite. The enhancement in hardness can be attributed to the strong interfacial bonding between fiber and matrix which play an essential role in transferring load between the phases[\u003cspan class=\"CitationRef\"\u003e23\u003c/span\u003e]. Strong interfacial bonding enhances stress transfer and helps distribute applied loads more evenly throughout the composite leading to higher hardness value. Moreover, the stiffness and rigidity of reinforced moringa fiber contributed to overall stiffness and rigidity.\u003c/p\u003e\n \u003c/div\u003e\n \u003cdiv class=\"BlockQuote\"\u003e\n \u003cp\u003eFurther, addition of rGO into the composite has significant effect on increasing the hardness of the composite which can be attributed to enhance interfacial bonding due to proper dispersion of rGO in composite. This facilitates better stress distribution and increased resistance to indentation, contributing to higher hardness values.\u003c/p\u003e\n \u003c/div\u003e\n\u003c/div\u003e\n\u003cdiv id=\"Sec12\" class=\"Section2\"\u003e\n \u003ch2\u003eThermal Analysis\u003c/h2\u003e\n \u003cp\u003eThermal conductivity is a material property that quantifies a material\u0026apos;s ability to conduct heat, determining how easily heat can pass through a material. In composite materials, thermal conductivity is influenced by the conductivities of the constituent materials, their volume fractions, and the nature of the interfaces. Heat in these materials is primarily carried by lattice vibrations known as phonons. In the Fig. \u003cspan class=\"InternalRef\"\u003e7\u003c/span\u003e it can be observed that the thermal conductivity of MOF/EPOX and rGO/MOF/EPOX composite increases with increasing temperature, which can be explained by the Debye model of specific heat and thermal conductivity. At low temperatures, the phonon contribution to thermal conductivity increases as more phonon modes are excited. As temperature increases, phonon-phonon scattering becomes significant, affecting thermal conductivity. Furthermore, as shown in the Fig. \u003cspan class=\"InternalRef\"\u003e7\u003c/span\u003e, the thermal conductivity of the rGO/MOF/EPOX composite is significantly higher compared to the MOF/EPOX composite. This enhancement in thermal conductivity can be attributed to the high thermal conductivity of rGO, due to its two-dimensional structure and strong sp\u003csup\u003e2\u003c/sup\u003e carbon-carbon bonds. Also the alignment of fibers within the composite has the potential to influence thermal conductivity.\u003c/p\u003e\n \u003cdiv class=\"BlockQuote\"\u003e\n \u003cp\u003eThe presence of rGO in the composite provides highly efficient pathways for heat transfer and better phonon coupling by bridging the gaps between fibers and the matrix[\u003cspan class=\"CitationRef\"\u003e23\u003c/span\u003e]. In composite materials, multiple interfaces can hinder heat transfer. However, the well-dispersed rGO nanopowder in the composite helps to reduce this interfacial thermal resistance, promoting effective heat transfer. As temperature rises, anharmonic effects become more pronounced, leading to increased phonon scattering. The higher population of phonons results in more frequent phonon-phonon scattering events, which hinder the flow of thermal energy, thereby reducing the mean free path of phonons and decreasing the thermal conductivity. Thermal conductivity play a crucial role in the performance and stability of microwave absorbing materials. By optimizing thermal conductivity, these materials can be fabricated to efficiently attenuate microwave energy while maintaining thermal stability and compatibility.\u003c/p\u003e\n \u003c/div\u003e\n\u003c/div\u003e\n\u003cdiv id=\"Sec13\" class=\"Section2\"\u003e\n \u003ch2\u003eMicrowave absorption properties\u003c/h2\u003e\n \u003cdiv class=\"BlockQuote\"\u003e\n \u003cp\u003eThe gradual decrease in the dielectric constant for MOF/EPOX and rGO/ MOF/EPOX composite can be attributed to the material\u0026apos;s microstructure and the interactions between the composite components[\u003cspan class=\"CitationRef\"\u003e24\u003c/span\u003e]. When Moringa oleifera fibers added to the epoxy matrix the interfacial areas between the fibers and the matrix increases which causes polarization effects leading to decrease of overall dielectric constant as shown in Fig. \u003cspan class=\"InternalRef\"\u003e8\u003c/span\u003e. At lower frequencies, different polarization mechanisms such as electronic, ionic, dipolar, and interfacial polarization contribute to the dielectric constant. As frequency increases, these polarization mechanisms cannot keep up with the rapidly changing electric field. Consequently, the contribution of these polarizations diminishes, leading to a decrease in the dielectric constant. At higher frequencies, the time available for dipole orientation is reduced, causing a lag in response[\u003cspan class=\"CitationRef\"\u003e25\u003c/span\u003e]. This relaxation effect results in a lower dielectric constant at higher frequencies. The addition of rGO increases dielectric constant (\u0026epsilon;\u0026rsquo;) at lower frequencies from 3.28 to 3.35 and at higher frequencies increase from 2.94 to 3.02 compared to MOF/EPOX composite. This may be attributed to rGO due to its high surface area and multiple conductive pathways, facilitating the accumulation and retention of electrical charges within the composite structure[\u003cspan class=\"CitationRef\"\u003e25\u003c/span\u003e]. At higher frequencies, interfacial polarization effects become less significant because the dipoles at the interfaces cannot reorient quickly enough, leading to a reduction in the overall dielectric constant. In the X-band frequency range, the dielectric constant decreases because the material\u0026apos;s response to the electric field is no longer in phase, resulting in reduced polarization efficiency and a lower dielectric constant.\u003c/p\u003e\n \u003c/div\u003e\n \u003cp\u003eThe dielectric loss (\u0026epsilon;\u0026rdquo;) of MOF/EPOX and rGO/ MOF/EPOX composite increases gradually with increase of frequency as shown in Fig. \u003cspan class=\"InternalRef\"\u003e9\u003c/span\u003e. This may be attributed due to enhanced surface roughness by the alkali treatment and introduces polar functional groups, leading to increased interfacial polarization and dielectric loss. Further, the incorporation of rGO enhances the conductivity of the composite, resulting in increased energy dissipation and dielectric loss[\u003cspan class=\"CitationRef\"\u003e26\u003c/span\u003e]. Moreover, the synergistic effect between alkali-treated fibers and rGO promotes enhanced interfacial interactions, which contribute to the gradual rise in dielectric loss with increasing frequency in the X-band range.\u003c/p\u003e\n \u003cp\u003eThe increase in tangent loss with frequency in MOF/EPOX and rGO/ MOF/EPOX composites can be attributed to the microstructure and material properties of the composites as shown in Fig. \u003cspan class=\"InternalRef\"\u003e10\u003c/span\u003e. At lower frequencies, the movement of molecules or particles within the composite material is relatively slow. This allows for better alignment and organization of the composite components, resulting in lower friction and energy dissipation at the interfaces between the epoxy matrixes, rGO coatings. However, as the frequency increases, the movement becomes more rapid, leading to increased friction and energy dissipation at these interfaces. Again, at higher frequencies, the polarization of molecules and dipoles may not be able to keep up with the rapidly changing electric field, leading to increased energy loss due to dielectric relaxation. As per Maxwell\u0026rsquo;s electromagnetic wave equation in an ionized medium[\u003cspan class=\"CitationRef\"\u003e27\u003c/span\u003e]\u003c/p\u003e\n \u003cdiv id=\"Equ1\" class=\"Equation\"\u003e\n \u003cdiv class=\"EquationNumber\"\u003e\u003cimg src=\"data:image/png;base64,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\" width=\"577\" height=\"98\"\u003e\u003c/div\u003e\n \u003c/div\u003e\n \u003cp\u003ewhere \u0026epsilon;* is complex permittivity and \u0026mu;* \u0026nbsp;is magnetic permeability of the medium of propagation, the propagation of electromagnetic waves in materials depends on their dielectric properties\u003c/p\u003e\n \u003cp\u003eIn heterogeneous materials like composites, variations in dielectric properties can lead to non-uniform electric field distributions, especially at interfaces between phases with different permittivity. This can cause local concentration of electric field lines, resulting in enhanced energy dissipation and increased tangent loss at higher frequencies. Further, dispersion mechanisms such as interfacial polarization, dipolar relaxation, and conductive losses can contribute to frequency-dependent tangent loss due to addition of rGO in composites, the conductivity of the rGO layers may lead to increased losses at higher frequencies due to eddy current losses and other conductivity-related mechanisms.The variation of reflection loss for MOF/EPOX and rGO/ MOF/EPOX composites with frequency shown in Fig. \u003cspan class=\"InternalRef\"\u003e11\u003c/span\u003e can be explained based on Maxwell\u0026apos;s wave propagation in dielectric media. Maxwell\u0026apos;s equations in response to electric and magnetic fields interaction with matter, including dielectric materials like composites. The dielectric permittivity (\u0026epsilon;*) of a material determines how much the material can polarize in response to an applied electric field. In composites, variations in permittivity arise from the different constituents (epoxy, Moringa oleifera fibers, and rGO coatings) and their spatial distribution. At lower frequencies, the wavelength of the incident electromagnetic wave is longer, and the polarization of the composite material can effectively follow the changing electric field. This results in lower reflection loss \u0026minus;\u0026thinsp;10.80dB for MOF/EPOX and \u0026minus;\u0026thinsp;13.86dB for rGO/ MOF/EPOX composite because the incident wave can penetrate deeper into the material before being reflected back.\u003c/p\u003e\n \u003cp\u003eHowever, at higher frequencies, where the wavelength becomes comparable to or smaller than the dimensions of the composite constituents, the mismatch in permittivity at interfaces causes more significant reflection loss at frequency 11.812GHz are found to be -11.46dB and \u0026minus;\u0026thinsp;17.71dB for MOF/EPOX and rGO/ MOF/EPOX respectively due to high mismatch of impedance as observed in the present investigation. Again at lower frequencies, the penetration depth of the incident wave is larger, allowing for more opportunities for absorption and dissipation of energy within the material[\u003cspan class=\"CitationRef\"\u003e28\u003c/span\u003e]. However, at higher frequencies, where the penetration depth decreases, multiple scattering events at interfaces become more significant, leading to increased reflection loss. Further, the formation of large no. of resonance cavities as observed in SEM images of the composite material lead to frequency-dependent reflection behavior. As the material has high reflection loss in MOF/EPOX and rGO/ MOF/EPOX composites it corresponds to microwave absorption efficiency increase from 92.06\u0026ndash;98.42% which is due to impregnation of rGO in MOF/EPOX composite.\u003c/p\u003e\n\u003c/div\u003e"},{"header":"Conclusion","content":"\u003cp\u003eThe study demonstrates the significant potential of Moringa Oleifera fiber (MOF) as a sustainable and effective reinforcement material for electromagnetic shielding applications. The incorporation of reduced graphene oxide (rGO) into the MOF/epoxy (EPOX) composite enhances both the electromagnetic shielding properties and the mechanical strength of the material. The comprehensive analysis, including morphological, structural, mechanical, thermal, and microwave absorption properties, confirms that the rGO/MOF/EPOX composite exhibits superior performance compared to traditional materials. The enhanced dielectric properties and increased absorption efficiency due to the addition of rGO, improves the complex permittivity and leads to a remarkable reflection loss. The SEM and optical microscopy analyses reveal a well-dispersed and uniform distribution of rGO, contributing to improved interfacial bonding and mechanical integrity. The water absorption tests indicate reduced hydrophobicity, enhancing the composite's durability in humid environments. Mechanical testing shows significant improvements in hardness and thermal conductivity, indicating that the composite can withstand various operational conditions. The dielectric constant and loss tangent analyses illustrate the composite's ability to interact efficiently with electromagnetic waves, leading to effective shielding performance. The reflection loss measurements confirm the composite's capability to minimize electromagnetic interference effectively. Overall, the rGO/MOF/EPOX composite emerges as a promising candidate for electromagnetic shielding applications, offering a sustainable, lightweight, and high-performance alternative to conventional materials. The study establishes that rGO/MOF/EPOX composites exhibit an enhancement of microwave absorption efficiency of 92.06\u0026ndash;98.42% in the X-band frequency range making them a sustainable and effective alternative for advanced EM shielding materials. Further, this study not only contributes to the development of advanced composite materials but also paves the way for the utilization of waste materials in high-tech applications, aligning with the principles of sustainability and eco-friendliness. Future research could further optimize the composite's properties and explore its potential in various industrial applications, addressing the growing concerns of electronic pollution and electromagnetic interference.\u003c/p\u003e"},{"header":"Declarations","content":"\u003ch2\u003eCompeting Interests\u003c/h2\u003e\n\u003cp\u003eThe authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence this paper.\u003c/p\u003e\n\u003ch2\u003e\u003cstrong\u003eCompeting interests\u003c/strong\u003e\u003c/h2\u003e\n\u003cp\u003eThe authors have no financial or non-financial interests to disclose.\u003c/p\u003e\n\u003ch2\u003eFunding\u003c/h2\u003e\n\u003cp\u003eThe research was a part of academic programme. The authors declare that no funds, grant or other support were received during the preparation of this manuscript or study.\u003c/p\u003e\n\u003ch2\u003eAuthor Contributions\u003c/h2\u003e\n\u003cp\u003eAll the authors contributed equally in the experimental design, analysis and preparation of manuscript.\u003c/p\u003e\n\u003ch2\u003eAcknowledgement\u003c/h2\u003e\n\u003cp\u003eThe authors are grateful to the Science and Technology Department, Govt. of Odisha for sanctioning the Project No.3692 /ST and Vice-Chancellor of the Veer Surendra Sai University of Technology, Burla, for laboratory facilities to execute the project\u003c/p\u003e\n\u003ch2\u003eData Availability\u003c/h2\u003e\n\u003cp\u003eEnquiries about data availability should be directed to the authors.\u003c/p\u003e"},{"header":"References","content":"\u003col\u003e\n\u003cli\u003eZhang, Q., Liang, Q., Zhang, Z., Kang, Z., Liao, Q., Ding, Y., Ma, M., Gao, F., Zhao, X., Zhang, Y.: Electromagnetic Shielding Hybrid Nanogenerator for Health Monitoring and Protection. 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Technol. 20, 2188\u0026ndash;2220 (2022). https://doi.org/10.1016/j.jmrt.2022.07.140\u003c/li\u003e\n\u003c/ol\u003e"}],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":true,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":false,"hideJournal":false,"highlight":"","institution":"","isAcceptedByJournal":true,"isAuthorSuppliedPdf":false,"isDeskRejected":"","isHiddenFromSearch":false,"isInQc":false,"isInWorkflow":true,"isPdf":false,"isPdfUpToDate":true,"isWithdrawnOrRetracted":false,"journal":{"display":true,"email":"[email protected]","identity":"waste-and-biomass-valorization","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"wave","sideBox":"Learn more about [Waste and Biomass Valorization](http://link.springer.com/journal/12649)","snPcode":"12649","submissionUrl":"https://submission.nature.com/new-submission/12649/3","title":"Waste and Biomass Valorization","twitterHandle":"","acdcEnabled":true,"dfaEnabled":true,"editorialSystem":"em","reportingPortfolio":"Springer Hybrid","inReviewEnabled":true,"inReviewRevisionsEnabled":false},"keywords":"Waste Moringa peel fiber, electromagnetic interference, reflection loss, complex permittivity, electromagnetic shielding","lastPublishedDoi":"10.21203/rs.3.rs-4485842/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-4485842/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003cp\u003eThe advent of the ultra-first digital system marked a transformative era in technology, particularly in monitoring natural phenomena through electromagnetic waves. For safeguard of the electronic instruments and mitigate electromagnetic interference, the utilization of electromagnetic absorbing materials has emerged as a crucial solution. In this context, the Moringa Oleifera fiber (MOF) which is exploded away as a waste material has the potential to disseminate the intensity of high intense electromagnetic wave plays a crucial role in presence of reduced graphene oxide (rGO) with epoxy as (rGO/MOF/EPOX) composite \u0026nbsp;stand out as a promising approach. When incorporated into an epoxy matrix, MOF form a synergistic blend that not only provides electromagnetic shielding but also offers mechanical strength and stability. The change of complex permittivity of the material from 3.2 to 3.35 with 1wt% of rGO, produces a remarkable reflection loss along with increase of absorption efficiency from 68.38 % to 87.41%.The morphology of rGO/MOF/EPOX composite are analyzed through SEM which supports the ability of the composite to be a good electromagnetic shielding material. The physical, mechanical and thermal property MOF/EPOX composite has been evaluated in presence of rGO and discussed with correlation of dielectric properties of the material.\u003c/p\u003e","manuscriptTitle":"Reduced GO decorated waste Moringa oleifera fiber composite for sustainable electromagnetic shielding material","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2024-08-23 09:49:41","doi":"10.21203/rs.3.rs-4485842/v1","editorialEvents":[{"type":"communityComments","content":0},{"type":"reviewerAgreed","content":"","date":"2024-07-29T14:35:08+00:00","index":0,"fulltext":""},{"type":"reviewersInvited","content":"","date":"2024-07-28T12:20:07+00:00","index":"","fulltext":""},{"type":"editorInvited","content":"Waste and Biomass Valorization","date":"2024-06-12T22:13:46+00:00","index":"","fulltext":""},{"type":"editorAssigned","content":"","date":"2024-05-28T11:52:19+00:00","index":"","fulltext":""},{"type":"submitted","content":"Waste and Biomass Valorization","date":"2024-05-27T10:52:32+00:00","index":"","fulltext":""}],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"waste-and-biomass-valorization","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"wave","sideBox":"Learn more about [Waste and Biomass Valorization](http://link.springer.com/journal/12649)","snPcode":"12649","submissionUrl":"https://submission.nature.com/new-submission/12649/3","title":"Waste and Biomass Valorization","twitterHandle":"","acdcEnabled":true,"dfaEnabled":true,"editorialSystem":"em","reportingPortfolio":"Springer Hybrid","inReviewEnabled":true,"inReviewRevisionsEnabled":false}}],"origin":"","ownerIdentity":"b7928c26-c72f-4126-b26d-96ac7afb89c9","owner":[],"postedDate":"August 23rd, 2024","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"published-in-journal","subjectAreas":[],"tags":[],"updatedAt":"2024-11-18T19:25:12+00:00","versionOfRecord":{"articleIdentity":"rs-4485842","link":"https://doi.org/10.1007/s12649-024-02804-w","journal":{"identity":"waste-and-biomass-valorization","isVorOnly":false,"title":"Waste and Biomass Valorization"},"publishedOn":"2024-11-17 15:57:46","publishedOnDateReadable":"November 17th, 2024"},"versionCreatedAt":"2024-08-23 09:49:41","video":"","vorDoi":"10.1007/s12649-024-02804-w","vorDoiUrl":"https://doi.org/10.1007/s12649-024-02804-w","workflowStages":[]},"version":"v1","identity":"rs-4485842","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-4485842","identity":"rs-4485842","version":["v1"]},"buildId":"qtupq5eGEP_6zYnWcrvyt","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}