Composite Materials Research Articles

Design of heterostructure photocatalysts based on layered perovskite-like bismuth silicate

Heterostructure photocatalysts attract a lot of attention of researchers thanks to their enhanced photocatalytic performance. Herein, we focus on the formation of the p-n type heterojunction based on bismuth metasilicate Bi2SiO5 and β-Bi2O3. To date, there are some publications dedicated to these objects, however, the monitoring of the phase composition in the Bi2O3-Bi2SiO5 system and strong evidence of the heterostructure formation in the composite material have not been provided together. At first, we show with quantum-chemical calculations that such interface is possible to design. After that, using XRD in situ we clearly show the pathway of formation of Bi2SiO5 by consuming β-Bi2O3 phase with increasing of temperature. Such results allow monitoring the phase content of the composite material. Finally, we choose two calcination modes to prepare the samples. Based on the results of HRTEM, DRS, XRD, IR and Raman data we clearly show the difference between the mechanical mixture of the semiconductors and generated heterostructure material. Photocatalytic properties of the samples are tested in photodegradation of Rhodamine B under different wavelength of LEDS. Under visible light (470 nm) the heterostructure demonstrates better catalytic activity. Additionally, using air flow and trapping agents it is demonstrated that the holes h+ mainly take part in deethylation of the dye.

Preparation of microalgae-based carbon materials with Ni(OH)2 doping and their electrochemical performance

Supercapacitors are a new type of energy storage devices with many advantages. In this study a novel composite material named NiC were synthesized to improved their electrochemical performance in supercapacitors. It was composite of Ni(OH)2 and microalgae-based N-doped activated carbon materials. Activated carbon material prepared from defatted microalgae was excellent electrode material because of their nitrogen-rich characterization and porous structure. The Ni(OH)2 as a metallic material could provide considerable pseudo-capacitance for capacitors. In this study, Ni(OH)2 was successfully doped into carbon materials using a hydrothermal method at a temperature of 150 °C for 4 h. The flower-like structure of metallic materials was observed in SEM images and two forms of elemental Ni ions (Ni3+ and Ni2+) were detected in XPS. The porosity of the composite materials NiC was retained to some extent (specific surface area of 502 m2/g for sample NiC10). Moreover, the specific capacitance value of composite material NiC20 was increased by 190 % compared to its parent carbon material, indicating that the capacitive performance of the composite materials was significantly improved. The capacitance retention of NiC20//NiC20 in a two-electrode system was up to 75.29 % over 5000 cycles. This research will provide necessary information for high-performance electrochemical materials based on microalgae-based carbon materials.

Z-scheme BiOBr/WS2 heterojunction with integrated photocatalytic degradation and photothermal water evaporation for effective dye wastewater purification

The restoration of water resources and the optimization of solar energy use are critical challenges. In this study, hydrophilic BiOBr/WS2 Z-scheme heterojunctions were prepared using a series of reactions for solar interface water evaporation and photocatalytic degradation of RhB. WS2 nanoparticles were deposited on the surface of titanium mesh using a hydrothermal method, and BiOBr nanosheets were further modified on WS2 using a successive ionic layer adsorption reaction (SILAR) method and solvothermal method. The relatively broad absorption range of WS2 in the full spectrum resulted in enhanced light absorption and improved light utilization of BiOBr/WS2. The formation of Z-scheme heterojunction between BiOBr and WS2 improved the hydrophilicity of the material, enhanced the photocatalytic degradation of organic pollutants in BiOBr/WS2 composite materials, and improved the solar interface water evaporation performance. The degradation rate of RhB by BiOBr/WS2 could reach 95.6% under one solar irradiation, and the photothermal water evaporation rate could reach 1.81 kgꞏm-2ꞏh-1. This study solved the problem of dye enrichment on solar absorber and provided a new way to construct an efficient solar interfacial water evaporation-photocatalytic system to treat dye wastewater.

High-temperature thermochemical conversion of iron ore tailings into diopside and akermanite-based composite materials

Iron ore tailings (IOTs), the residue materials generated during iron ore processing, pose environmental challenges due to their massive volume and potential impact on ecosystems. This study proposes a sustainable approach to manage and utilize this solid waste by converting it into value-added composite materials through high-temperature thermochemical reactions. Experiments are conducted in a tubular reactor at various reaction temperatures and times, and the resulting product samples are comprehensively characterized to elucidate their chemical compositional, physical, microstructural, thermal, and electrical properties. The results reveal that at optimal reaction temperatures (1230–1260 °C) and reaction times (20–120 min), the synthesized product is predominantly composed of diopside (CaMgSi2O6) and akermanite (Ca2MgSi2O7). Additionally, we demonstrate that the product can be diopside-rich or akermanite-rich when blending silica and MgO powders into the IOTs to control the starting material composition, opening a promising avenue for large-scale sustainable utilization of industrial solid waste.

Co-use of laser texturing and graphene synthesis

The article is devoted to the study of wettability on combined textured surfaces (laser texturing): textured copper and graphene (Cu/G) synthesized on copper. For the first time the combined effect of various textures after laser texturing and graphene synthesis on corrosion current and wettability before and after corrosion is investigated. Previous research works have shown that the surface wettability after laser texturing varies greatly over time, from superhydrophilic to highly hydrophobic. However, the present work shows that the combined effect of laser texturing and graphene synthesis allows stabilizing the wettability of textured samples over time, as well as significantly reducing the impact of corrosion on the contact angle. The droplet contact angle changes slightly over time after corrosion. The smallest change in the contact angle corresponds to the Cu/G surface for textures with craters. At that, the corrosion current of the textured Cu/G sample is reduced 12–14 times, compared with the textured copper. The use of textures with craters provides higher corrosion resistance than in the case of textures without craters. The performed XPS analysis reveals that that the textured wall with craters has a maximum peak C = C (C1s XPS spectra). A new mechanism is proposed to explain the different wettability inversion period for textured copper with graphene synthesis. The wettability of textured surfaces is simulated using molecular dynamics methods. The contact angle of the nanodrop depends on both the textures and the hydrophilicity of the polished surface. The obtained results will be useful for the development of combined methods and composite materials in materials science to control wettability, stabilize surface properties, as well as to counteract aggressive environmental effects.

Construction of piezoelectric fenton-like system over BaTiO3/α-FeOOH for highly efficient degradation of demethylchlortetracycline

Heterogeneous Fenton-like system is a promising technique for wastewater treatment, while Fe2+ regeneration limits its degradation efficiency. Piezoelectric materials can produce free electrons under mechanical stress. Based on this, a piezoelectric Fenton-like system coupling piezoelectric effect and Fenton-like reaction was proposed. Composite material BaTiO3/α-FeOOH was synthesized by sol–gel and hydrothermal method. Under ultrasonic vibration BaTiO3 continuously generated free electrons, which reduced Fe3+ to Fe2+ and realized Fe3+/Fe2+ cycle. The piezoelectric Fenton-like system based on BaTiO3/α-FeOOH was used to remove demethylchlortetracycline (DMCT) from water. The degradation ratio of DMCT can reach 100 % within 5 min, and the coupled system exhibited excellent adaptability and stability. Free radical capture and quantitative detection determined that •OH and •O2− were the main active oxygen species. A comprehensive catalytic mechanism was proposed and supported by energy band structure analysis, finite element method simulation, and Density Functional Theory (DFT) simulation calculations. The piezoelectric electrons generated by BaTiO3 were transfered to α-FeOOH to improve the Fe3+/Fe2+ cycle. In addition, the possible degradation mechanism of DMCT was proposed through Ultra Pressure Liquid Chromatography-Mass Spectrometry (UPLC-MS) measurement and DFT calculation, and the overall pollution toxicity of DMCT was assessed according to toxicity prediction. Overall, this work provided a new insight on coupling effect between piezoelectric effect and Fenton-like reaction.

Influence of Stacking Sequence on the Mechanical Properties of Banana-Glass Fiber Hybrid Laminates for Automotive Shells

The development of composite materials using natural fibers has garnered significant global research interest. Banana fibers, due to their abundant availability and rapid growth cycle, present a promising option for composite material development. When combined with synthetic fibers to form hybrid composites, the resulting material may exhibit significantly improved properties, which is desirable for automotive body manufacturing. The hybrid properties of such composites, however, remain largely unexplored and require thorough evaluation. This study investigates the mechanical performance of hybrid laminated composites fabricated from banana and woven glass fibers bonded with epoxy resin. The composites were produced using non-crimp banana (B) fiber and woven glass (WG) fiber fabrics through the hand lay-up process with four distinct stacking sequences: [WG/B-0⁰/B-0⁰/WG], [WG/B-0⁰/B-45⁰/WG], [WG/B-0⁰/B-60⁰/WG], and [WG/B-0⁰/B-90⁰/WG]. Comprehensive mechanical testing, including tensile, flexural, impact, and hardness tests, along with environmental testing (water diffusion) was conducted in accordance with ASTM standards. Results indicated that the [WG/B-0⁰/B-0⁰/WG] configuration exhibited the highest tensile strength, while the [WG/B-0⁰/B-60⁰/WG] configuration achieved superior flexural strength. The [WG/B-0⁰/B-45⁰/WG] configuration demonstrated the highest impact strength and energy absorption. Rockwell hardness testing revealed that the average hardness numbers for all orientations were approximately 79, which is considered moderate for composite materials. Water absorption tests showed maximum water saturation in [WG/B-0⁰/B-90⁰/WG] of ∼5.5%, where the other laminates had water saturation between 4.5-4.9%. The microscopic analysis of the [WG/B-0⁰/B-45⁰/WG] laminate suggests fiber-matrix debonding and fiber pull-out as the major cause of failure under tensile and flexural loading. These findings suggest that the hybrid laminated composites, particularly the [WG/B-0⁰/B-0⁰/WG] and [WG/B-0⁰/B-45⁰/WG] configurations, exhibit mechanical properties suitable for automotive body applications.

Fe-based nanozyme with photothermal activity prepared from polymerization-induced self-assembly assays boosts the recovery of bacteria-infected wounds

Nowadays, the overuse of antibiotics has escalated bacterial infections into an increasingly severe global health threat. Developing non-antibiotic treatments has emerged as a promising strategy for treating bacterial infections. Notably, nanozyme-based composite materials have garnered growing interest. Therefore, the efficient preparation of nanozyme is important. Herein, we have presented an efficient method to prepare Fe-based nanozyme through polymerization-induced self-assembly assay to kill bacteria efficiently, which could significantly enhance the healing of infected wounds. Through polymerization-induced self-assembly assay, a large number of uniformly sized micelles, bearing imidazole groups, could be efficiently prepared. These nanoparticles subsequently chelate with Fe ions, followed by pyrolysis and etching processes, resulting in the production of uniformly small-sized nanozymes with high adsorption activity in the near-infrared region. The composite materials could effectively eradicate bacteria via a synergistic strategy of photothermal and catalytic therapies under infected microenvironments. In vivo animal models with full-thickness wounds showed that combination therapy not only eradicates 98 % of the bacteria but also significantly accelerates wound healing. This work underscores the utility of polymerization-induced self-assembly in the preparation of nanozymes and reveals promising applications of nanozymes in wound healing. Statement of significanceThis research introduces a functional nanozyme with photothermal activity, synthesized through polymerization-induced self-assembly, offering a promising non-antibiotic strategy to combat bacterial infections. This strategy enhances wound healing by combining photothermal and catalytic therapies, effectively eradicating drug-resistant bacteria while minimizing damage to healthy tissue. Our findings hold significant implications for the development of advanced antibacterial treatments and offer a robust assay to prepare nanozyme with small sizes. The prepared functional nanoparticles have a potential in wound healing, addressing a critical need in the face of rising antibiotic resistance.

Facile synthesis of CoFe/C nanoparticle embedded in nitrogen and sulfur co-doped reduced graphene oxide nanocomposites for electromagnetic wave absorption

Three-dimensional metal–organic framework derivatives (MOFs) offer significant potential for the absorption of electromagnetic waves (EMW). However, the discrepancy in impedance matching restricts their ability to absorb EMW efficiently. This study synthesized a novel composite material, CoFe/C@N, S-rGO, by combining diazo coupling reactions, solvothermal techniques, and high-temperature pyrolysis. The composite consists of cobalt iron/carbon (CoFe/C) nanoparticles embedded in N and S co-doped reduced graphene oxide (N, S-rGO). The co-doping of N and S on graphene oxide (SGO) resulted in numerous defects and disordered sites, which generated interfacial and dipole polarization. The EMW absorption characteristics of the CoFe/C@N, S-rGO can be tuned by varying the quantity of SGO added. Notably, at an SGO concentration of 60 mg, the produced composite exhibits a minimal reflection loss of −53.8 dB, while a thickness of 4.0 mm yields an effective absorption bandwidth of 7.2 GHz. This material’s exceptional EMW absorption capabilities are primarily attributed to interface polarization, multiple reflections, dipole polarization, natural resonance, and eddy current loss. The findings of this study provide a potential solution for enhancing the impedance matching and electromagnetic wave absorption performance of MOFs.

Role of Sulfur in Enhancing UV‐Light Absorption and Photoelectrochemical Performance of ZnO/N,S‐doped CQDs Nanocomposite

AbstractThe modification of ZnO, such as transforming it from 1‐D to 3‐D nanostructures or compositing it with carbon‐based materials, has been extensively explored to enhance light energy harvesting and reduce electron‐hole recombination‐key limitations of ZnO. Herein, the effect of different composite materials, specifically nitrogen‐doped carbon quantum dots (N‐CQDs) and nitrogen, sulfur‐doped carbon quantum dots (N,S‐CQDs), on ZnO's morphology and photocurrent response was studied. Various morphologies were synthesized on conductive glass substrate using a one‐pot hydrothermal method, including flower‐like structure for ZnO/N‐CQDs (∼d = 0.9 µm) and multilayered microspheres for ZnO/N,S‐CQDs (∼d = 1.1 µm). The inclusion of sulfur atoms in the composite resulted in a reduced bandgap value from 3.22 to 3.11 eV, along with enhanced light absorption efficiency and improved separation of photogenerated electron‐hole pairs. Furthermore, the crystallinity of ZnO/N,S‐CQDs was significantly enhanced compared to ZnO without sulfur doping. These improvements were reflected in the photoelectrochemical (PEC) measurements, where ZnO/N,S‐CQDs showed a current density of 21.8 µA/cm2 at 0.5 V (vs. Ag/AgCl), which is 5.5 times higher than that of ZnO/N‐CQDs (4.0 µA/cm2). These findings demonstrate that sulfur doping improves photocatalytic efficiency, making 3D ZnO/N,S‐CQDs a promising candidate for various UV‐driven PEC applications.

An ultrasonic Lamb wave-based non-linear exponential RAPID method for delamination detection in composites

Accurate detection of defects, particularly delamination, in carbon-fiber reinforced polymer (CFRP) composites is crucial but challenging. This study proposes a baseline-free Lamb wave damage imaging framework that incorporates an adaptive time-reversal technique, and a nonlinear exponential reconstruction algorithm for probabilistic inspection of defects (NE-RAPID) in composites. The framework combines two image fusion strategies: full-summation and full-multiplication. NE-RAPID enhances the traditional RAPID algorithm by replacing linear weights with faster-decaying exponential weights, which improves the localization of delamination and other defect regions with higher resolution. A nonlinear exponential weight is introduced to address uneven probability distributions caused by the non-uniform density of the sensor network, thereby improving the accuracy and reliability of defect detection, including delamination. Experimental validation on CFRP composite plates demonstrates that NE-RAPID significantly outperforms RAPID. NE-RAPID achieves a maximum detection error of only 5.1 mm across different frequencies, while RAPID shows a much higher error of 34.41 mm. Furthermore, NE-RAPID produces sharper damage images with fewer artifacts, significantly reducing the risk of false positives. These findings indicate that NE-RAPID is a highly promising method for precise and reliable delamination detection in composite materials.

A hybrid model for accurate prediction of composite longitudinal elastic modulus

This research presents a novel hybrid model that integrates a physical-based empirical model with an Artificial Neural Network (ANN) to accurately predict the longitudinal modulus of elasticity for composites under compression. The study focuses on a composite material with a pore inclusion within an ABS plastic matrix, exploring various pore volumes, orientations, and shapes. As part of the proposed hybrid model, a regression-type neural network was trained in MATLAB® to predict and correct discrepancies between the Generalized Stiffness Formulation (GSF) homogenization-based modeling method and the collected compression experimental test results. Using MATLAB® neural network, random error datasets were used to train the feed-forward neural network, and the remaining error datasets were used for validating the performance of the proposed hybrid modeling scheme.The hybrid model demonstrated superior performance, achieving the lowest Mean Error (ME) of 0.1684864, Mean Absolute Error (MAE) of 1.051846, Mean Squared Error (MSE) of 3.500952, and highest R-squared of 0.998797. The proposed hybrid model outperformed both the Generalized Stiffness Formulation (GSF) and standalone ANN models. The significant improvement in prediction accuracy underscores the novelty and robustness of the hybrid approach in composite material modeling. Furthermore, this method can be used to refine any existing physical model by focusing on improving these established models to match experimental results and reducing the discrepancies, which offers a more efficient and attractive strategy for accurate predictions.

Comparison of Stress between Three Different Functionally Graded Hip Stem Implants Made of Different Titanium Alloys and Composite Materials

Comparison of Stress between Three Different Functionally Graded Hip Stem Implants Made of Different Titanium Alloys and Composite Materials

Synthesis of layered Co9S8-based composites for high-efficiency rotating evaporation of saturated brine

Harvesting freshwater via solar interfacial evaporation is a promising strategy with net-zero emissions. To achieve long-term stable freshwater acquisition, researchers have developed dynamic solar-driven water evaporators. However, these evaporators exhibit limited evaporation rates due to the insufficient photothermal conversion properties of the materials used. In this study, we prepared Co9S8/CoNiO2/Au composite materials through in-situ topological transformation, thereby improving the effect of the heterogeneous crystal lattice mismatch on electron transport. By embedding these materials into a spherical polyurethane sponge, we developed a new type of self-rotating evaporator with a solar full-spectrum absorbance of 95.84 %. The evaporator stably exhibited an evaporation rate of 3.10 kg m−2 h−1 within 240 h in saturated brine. The present work provides insights into the preparation of photothermal composites and the development of high-efficiency stable solar evaporators.

Synergistic regulation of dual thresholds: Hydroxyl occupancy and carbon species in the targeted catalytic hydrocracking of lignite

The preparation of carbon-based catalyst supports from low-grade lignite, followed by its self-catalytic hydrocracking to produce lignite-derived aromatic compounds, is crucial for achieving efficient lignite utilization and expanding aromatic compound sources. During lignite catalytic hydrocracking, the uncontrolled diffusive migration of active hydrogen (H*) and insufficient protection of aromatic rings reduce the yield of aromatic compounds. Using Heishan lignite as the raw material, we employed a relay process of thermal-induced self-assembly and oxidation-mediated carbon distortion for fabricating the Co3O4/AC&GC-S-600 composite material, which features an optimal hydroxyl occupancy ratio and a balanced combination of amorphous carbon/graphite carbon (AC/GC) types. The optimal hydroxyl occupancy threshold balances Co3O4 dispersion and hydrophilicity, facilitating the efficient formation and directional migration of H* through synergistic interaction between Co3O4 and H2O. The adequate threshold of AC/GC ratio regulates substrate adsorption, activation, and inhibition of aromatic hydrogenation, enhancing selective C–O bridge bond cleavage and preserving the unsaturation of aromatic rings. The synergistic regulation of dual thresholds promotes the rapid formation and the directional migration of H*, enabling efficient conversion of Heishan lignite to aromatic compounds (45.8% conversion, 80.8% selectivity) under mild conditions. Characterization techniques, experimental analyses, kinetic studies, and density functional theory calculations confirm that thermally induced self-assembly and oxidation-mediated carbon distortion are crucial for redistributing the carbon framework of the Heishan lignite matrix and regulating the optimal dual thresholds of hydroxyl occupancy and AC/GC types, which are essential for the catalytic hydrocracking of Heishan lignite to aromatic compounds. This strategy provides a scientific basis for selective catalytic production of lignite-based aromatic compounds, thereby supporting its clean and efficient utilization.

Stochastic approach to evaluate the shielding effectiveness of composite materials loaded with randomly oriented helices

AbstractThis letter proposes a method to calculate the expected value of the shielding effectiveness of a composite material slab, including a planar array of randomly oriented metal helices as chiral particles. Helix‐loaded concrete composite materials are advantageous for electromagnetic interference shielding applications. While planar periodic arrays of chiral particles have been extensively studied, this research discusses a non‐periodic array in which the helical particle axis direction in each unit cell is random. This method estimates the slab's shielding effectiveness by defining it as a random variable expanded into three independent basis‐like functions. Comparisons with full‐wave simulations show acceptable agreement across a wide frequency range, with a total RMS error of 0.9 dB. This study additionally includes an experimental measurement to validate the proposed method. This technique provides the initial step in developing an analytical method to analyse and estimate the transmitted power of general structures using a stochastic approach. Examples include concrete composites containing randomly distributed helical steel particles with significant shielding effectiveness.

Realization of the shape memory effect in a composite material PLA/Diopside with different supramolecular structures

This study explores the realization of the shape memory effect (SME) in composite materials composed of polylactide (PLA) filled with diopside particles exhibiting varied supramolecular structures, such as spherulites and amorphous lamellar structures. We investigated the influence of diopside filler on the thermomechanical properties and shape recovery behavior of PLA-based composites. Different supramolecular structures of PLA were achieved through controlled crystallization processes. Comprehensive characterization techniques, including differential scanning calorimetry (DSC), scanning electron microscopy (SEM), and dynamic mechanical analysis (DMA), were employed to elucidate the structure-property relationships. The results indicate that the diopside enhances the SME of PLA composites, with the degree of improvement being dependent on the specific supramolecular structure of the polymer matrix. Our findings provide insights into the design of advanced SMPs with tailored properties for potential applications in medicine.

Study on the mechanical properties and gamma/neutron radiation shielding performance of SnBi/B4C composite materials

The development of multifunctional shielding materials has become a hot research topic with the increasing requirements for radiation protection materials in terms of performance, weight and non-toxicity. In this study, non-toxic SnBi/B4C composites with different B4C contents (0, 3, 6, 9, 12 and 15wt%) were successfully prepared by powder metallurgy, and their mass attenuation coefficients, half-value layers, mean free paths, effective atomic numbers, and 0.025eV thermal neutron shielding performance. The results show that B4C plays a key role in regulating the mechanical properties and thermal neutron shielding properties of SnBi/B4C composites. When the B4C content was 9wt% (S3), the integrated mechanical properties of the composites were optimal, and the yield strength, tensile strength, and microhardness were enhanced by 31%, 32%, and 129%, respectively, compared with those of the samples without B4C. The radiation shielding effect is remarkable, the gamma-ray shielding performance in the energy range of 0.03-0.08MeV is better than that of Pb. Meanwhile, the S3 sample with only 3mm thickness can shield 99.7% of thermal neutrons, while the shielding rate of the S0 sample without B4C is only 5.2%. Comprehensive analyses show that the SnBi/B4C composites are superior in terms of environmental protection, mechanical properties, gamma-ray and thermal neutron shielding, with lighter weight and safer use. This finding provides a theoretical basis for the selection of efficient, non-toxic and diverse radiation shielding materials for medical and other special environments.

Impact of gamma radiation on marginal adaptation of nanohybrid composite and composition of dental hard tissues – Scanning electron microscopy and X-ray diffraction analysis: An in vitro pilot study

Aims: This pilot study aimed to compare the marginal adaptation of composite resin at the tooth-restoration interface, before and after radiation. Subjects and Methods: Fifteen extracted premolars were divided into 2 experimental groups (based on the timing of irradiation) and 1 control group of 5 teeth each. In Group I (control group), teeth were restored but not exposed to radiation at any stage, Group II: teeth were irradiated before cavity preparation and restoration, and Group III: after cavity preparation and restoration employing selective etch technique, teeth were exposed to radiation. The samples were then sectioned buccolingually to analyze the extent of the marginal gap under scanning electron microscopy and compositional alteration of dental hard tissues by X-ray diffraction study. The data collected were analyzed statistically. Statistical Analysis Used: The statistical software used was IBM SPSS version 23 New York, USA, and analysis was done using two-way ANOVA followed by Turkey’s post hoc test, this difference in the mean marginal gap between all three groups was nonsignificant (P ≥ 0.05). Results: In the control group (Group I), a minimum gap (4.203 µm ± 0.533) was observed at the tooth-restoration interface, indicating the highest level of adaptation as compared to Group II (5.816 µm ± 0.762) and Group III (4.862 µm ± 1.018). This suggests that radiation adversely affected the bonding between composite materials and both enamel and dentin, attributed to the alterations induced by radiotherapy in the chemical, physical, and morphological properties of both tooth structure and composite resin. Conclusions: Ionizing radiations adversely affect the bonding between enamel, dentin, and composite resin. Hence, restorative procedures should be performed before undergoing radiotherapy.

Fabrication of graphene oxide-reinforced polyvinyl alcohol and study effect of thermal annealing of GO/PVA nanocomposites on their properties

In the presented work, graphene oxide (GO) was obtained as a plate using the Hummer technique. X-ray diffraction (XRD) and Scanning Electron Microscopy (SEM) show the formation of pristine GO. Composite materials were prepared by adding different percentages of GO to polyvinyl alcohol (PVA) (2%GO/PVA, 3% GO/PVA, and 20% GO/PVA). To determine the effect of thermal annealing on the structure, physical properties, and morphology of the samples, thermal annealing of the samples was performed for 1 hour at temperatures (40°C, 70°C, and 110°C). Following that, to explore how the characteristics of GO/PVA composites vary with concentration and thermal annealing temperature, the structural, optical, and morphological features of the samples were determined using XRD, Fourier-transform infrared (FTIR), and Raman spectroscopy, as well as SEM used to investigate the properties of all samples. From the XRD results, by the increasing thermal annealing temperature, the space between the sheets is decreased. From Raman measurements, the ID/IG ratio for 2% and 3% GO/PVA composite materials increased with increasing temperature compared to the pristine GO. It indicates that the defect in the structure increases due to the effect of temperature.