Graphene Oxide Content Research Articles

Role of graphene oxide infusion in concrete to elevate strength and fire performance in construction concrete

The study is centered on optimizing graphene oxide (GO) concentration in M30 designer mix concrete, aiming to enhance its performance under elevated temperatures and fire conditions. The findings revealed a significant 40 % increase in compressive strength with the addition of 0.05 wt% GO to M30 grade concrete after 28 days of curing in water. GO played a crucial role in mitigating the impact of high temperatures under heating in furnace and fire exposure under flame, resulting in reduced crack formation and a delayed temperature rise during thermal loading. In heat resistance assessments, GO concrete exhibited a substantial delay in temperature rise compared to plain concrete under controlled furnace conditions, showcasing superior resistance to elevated temperatures. Thermogravimetric analysis and Differential TG analysis elucidated the superior retention of water and hydrated products in GO concrete, even after exposure to high temperatures. Fire exposure tests demonstrated that GO concrete exhibited a much lower surface temperature (less than 50 °C) opposite to the flame (flame temperature ∼ 700 °C) within a 15 cm width of concrete. Additionally, fewer and less severe cracks appeared in the GO concrete compared to plain concrete, showcasing its anti-spalling behavior. The altered matrix porosity of GO concrete, creating nano- and microscale channels, contributed to reduced vapor pressure and mitigated crack formation. This comprehensive study underscores the potential of GO as a versatile additive in concrete, offering enhancements in strength, heat resistance, and fire performance for sustainable and resilient infrastructure development.

Explanation based on thermodynamic parameters regarding effect of sensing film thickness and amount of graphene oxide on sensor performance in aniline, N-phenylglycine and graphene oxide based electrochemical heavy metal ion sensor

Background: To construct a heavy metal ion sensor, selectivity and sensitivity are the key important parameters to be taken care of. In our earlier work, film thickness and amount of graphene oxide (GO) content in a novel composite ANGO, synthesized from aniline, N-phenylglycine and GO was varied and sensing parameters including sensitivity, limit of detection (LOD), thermodynamic parameter which includes -∆Gad and charge transport parameter including barrier width (BW), d, of charge transfer based on Simmon’s model were evaluated and compared and an LOD of 800 ppt for Cd2+ was achieved using square wave voltammetry (SWV) withstanding interference from several ions. Methods: In this work, thermodynamic factors such as -∆Gad, ∆H, reorganization energy, partition coefficient and solvated ionic radius were used to explain the sensor performance with respect to film thickness and amount of GO. All the parameters were analyzed for different film thicknesses and amount of GO and a correlation was achieved. Finally, effect of electrochemical surface area of different polyaniline-based material on thermodynamic properties of detection process of Cd2+ was studied. Results: The variation of the thermodynamic properties for Cd2+ sensing with respect to film thickness and amount of GO were examined. Similarly, variation of thermodynamic properties for polyaniline based different sensing materials were examined. Correlation coefficients were developed from the thermodynamic parameters and the d values to explain the underlying mechanism behind improved sensor performance. Conclusions: This study can provide information on the thermodynamic properties which can be predicted from BW technique. The correlation coefficients would help in designing polyaniline based novel sensing film material with the need of lesser number of experiments.

Structural, optical, and dielectric properties of aminated PMMA/GO polymer nanocomposite for storage device applications

A series of aminated PMMA/GO polymer nanocomposite (PNG) were synthesized by solution mixing in two step process. The synthesized PNG samples were analysed using X-ray diffraction (XRD), Fourier transform infrared (FTIR), Scanning Electron Microscope (SEM), energy dispersive X-ray analysis (EDAX), Thermo-gravimetric, differential thermal analysis (TG-DTA), UV–Visible spectroscopy (UV–Vis) and impedance spectroscopy. The X-ray diffraction (XRD) data indicated the existence of crystalline nature in PMMA and the reduction of graphene oxide (GO) which is also confirmed by TGA and DTA results. The interaction between graphene oxide nanoparticles and the functionalized polymer matrix has been validated using FTIR investigations. The SEM and EDAX measurements demonstrated the homogeneous dispersion of graphene oxide (GO) over the surface of the produced samples. The UV–Vis spectroscopy analysis revealed that the optical energy gap values of nano composites decrease as the amount of graphene oxide nanoparticles increases. All samples exhibited higher relative permittivity at low frequencies which is a key factor for high energy density. As the concentration of GO increases, the maximum peak of dielectric loss tangent also shifted to higher frequency due to increase in interfaces. The β relaxation is dominant in non-polar PMMA due to the functionalisation and dispersion of GO. The AC conductivity values increased with increase in concentration of GO. The single semicircle in plot from impedance spectroscopy and the drop in bulk resistance values of PNG samples made them as a good material for energy storage devices like supercapacitors.

Investigating competition of strong interfacial interaction and chain scission in PBAT/EVOH/GO composite by rheological measurements

The blends of poly(butylene-adipate-co-terephthalate)/poly(ethylene-vinyl alcohol) (PBAT/EVOH) with varying amounts of graphene oxide (GO) were prepared by melt mixing. The localization of GO in PBAT and at the interface was confirmed by morphological evaluation. The dual effect of GO in degradation of PBAT phase and interface improvement of PBAT/EVOH was examined by rheological measurements and models. The results showed that the improved interfacial interaction induced by GO dominates its degradation effect in PBAT. Rheological analysis revealed that the interfacial elasticity originating from GO dominates the total elasticity of the system, resulting in an increase in the final elasticity. Generalized Fractional Zener (GFZ) model was used to analyze elasticity of the polymer blend and its nanocomposites with a well fit to the experimental results. Also, the Lee–Park model was used to distinguish the effects of particle interactions as well as interface strengthening from deterioration of matrix modulus due to PBAT degradation by GO. The increased elasticity of the interface showed that the strengthening effect of GO at the interface overcomes its degradation effect. Also, the application of Coran model to analyze phase homogeneity revealed a linear increase in interfacial interaction with GO concentration.

Evaluation of physical and mechanical properties of graphene oxide reinforced epoxy/Kevlar hybrid composites

Graphene is a miracle material with low density, excellent mechanical strength, electrical conductivity, molecular barrier properties and many other remarkable properties. Hence, recent research has been more focused on delving into various application areas of graphene. In this study, the effects of graphene oxide (GO) on the mechanical properties of composites based on epoxy resin and Kevlar fibers were investigated. The composites were fabricated by incorporating varying concentrations (1 %, 3 %, 5 %, 10 %, and 16 %) of graphene oxide (GO) into an epoxy matrix. The matrix was reinforced by two different wt.% (12.5 % and 25 %) of Kevlar fibers (KF). The hybrid composites were manufactured by hand lay-up process in a silicon mold at room temperature. Mechanical characterizations such as flexural, impact and hardness test exhibited an enhancement of the mechanical properties of the composites. Moreover, the measured density showed a significant reduction in density with increasing wt.% of GO. As a result, it was possible to fabricate a composite with a significant increase of specific flexural strength and specific flexural modulus. A microstructural analysis of the composites was performed by Scanning Electron Microscopy (SEM) and Energy Dispersive X-Ray Analysis (EDX). From the SEM images, it was revealed that the interphase bonding of the GO particles with Kevlar fibers and matrix was strong, thereby resulting in improved mechanical performance. It was observed that 5 wt% GO incorporation along with 25 wt% KF showed improved flexural strength, hardness and impact strength than that of sample fabricated only with Kevlar.

The Effects of Aging on Microstructures and Rheological Properties of Modified Asphalt with GO/SBS Composite.

This work aimed to investigate the effects of aging on the microstructures and rheological properties of modified asphalt with a GO/SBS composite, since the styrene-butadiene-styrene block copolymer is potentially compatible with graphene oxide (GO). The GO/SBS composites, which were used as a kind of modifier, were prepared via the solution-blending method. GO/SBS composites with varying GO contents were employed to prepare the GO/SBS-compound-modified asphalt (GO/SBS-MA). Then, the GO/SBS-MA underwent PAV (pressure aging vessel) or UV (ultraviolet) aging tests to simulate different aging circumstances. The microstructures of the asphalt binders were studied using FTIR (Fourier-transform infrared spectroscopy) and AFM (atomic force microscope) tests. Moreover, DSR (dynamic shear rheometer) and BBR (bending beam rheometer) experiments were carried out to investigate the rheological properties of the GO/SBS-MA. The results showed that the addition of GO improved the high-temperature stability of the asphalt binder while slightly impairing its performance at low temperatures. GO restrained the formation of carbonyl and sulfoxide groups as well as the breakdown of C=C bonds in the polybutadiene (PB) segment, promoting the anti-aging performance of GO/SBS-MA. Furthermore, the interactions between the GO/SBS and the asphalt binder resulted in the formation of needle-like aggregates, enhancing the stability of the asphalt binder. The asphalt binders with a higher content of graphene oxide (GO) exhibited not only a better high-temperature performance, but also a better aging resistance. It was concluded that the macroscopic properties and microstructures were significantly affected by GO, and a moderate increase in the amount of GO could contribute to a better aging resistance for GO/SBS-MA.

The thermal and hydrodynamic analysis in a heat sink with different configurations of shark scales-based fins

The development of efficient thermal management techniques in cooling systems will lead to achieving a higher power capacity for electronic devices. Extended surfaces such as fins and riblets effectively improve the heat transfer rate in heat sinks, but they can cause increasing the friction factor. In this numerical study, a novel configuration of fins is introduced according to the shark scales’ geometry to provide a trade-off between heat transfer rate and friction losses compared to simple fins in a microchannel cooling system. Also, the cooling effect of concentrations of graphene oxide (GO)+ silver (Ag)/water (H2O) and molybdenum disulfide (MoS2) + cobalt oxide Co3O4/water (H2O) nanofluids (1, 3, and 5 wt%) are investigated for the Reynolds number ranging from 130 to 525. The geometrical parameters and different materials such as copper, nickel, and silver are evaluated by ANSYS-FLUENT under steady-state conditions. The comparison of outlet temperature, pressure drop, and temperature difference by experimental results verifies the accuracy of the numerical model. The results indicate that increasing arc width from 1 mm to 1.5 mm reduces the maximum CPU (central processing unit) temperature by 5 K while the temperature uniformity index decreased by 9.96 % at 0.3 m/s of inlet flow rate. The novel configuration of fins results in a performance evaluation criterion (PEC) greater than 1 for GO+Ag/water nanofluids in all cases compared to simple circular fins.

Promoting Thermal Conductivity of Alumina-Based Composite Materials by Systematically Incorporating Modified Graphene Oxide

Small amounts of thermally conductive graphene oxide (GO) and modified GO are systematically introduced as a second filler to thermal interface materials (TIMs) consisting of alumina (Al2O3) particles and polydimethylsiloxane (PDMS). The surface of GO is covalently linked with an organic moiety, octadecylamine (ODA), to significantly improve the miscibility and dispersity of GO across the TIM matrix. Subsequently, two series of PDMS-Al2O3 composite TIMs are manufactured as a function of GO and ODA-GO content (0.25 wt%–2.5 wt%) to understand the effect of these second additives. The incorporation of GO into the Al2O3-PDMS composite materials generally increases the thermal conductivity (TC), ranging from 18% to 29%. Conversely, the use of ODA-GO further enhances the overall performance of TIMs (22–54%) by facilitating the dispersion degree of GO across the composite matrix. The great improvement in TC is presumably related to the formation of conductive pathways by uniformly integrating 2D-type GO flakes across spherical Al2O3 particle networks. The ability to simply regulate the polarity of the thermally conductive second filler can provide an idea for designing cost-effective and practical TIM-2-type pads that can be commercially applicable in between an integrated heat spreader and a heat sink.

Mitigation of drought stress effects on alfalfa (Medicago sativa L.) callus through CaO nanoparticles and graphene oxide in tissue culture conditions

Drought stress poses a significant threat to fertile soils worldwide, triggering profound physiological, biochemical, and molecular changes in plants that adversely impact agricultural productivity. This study explores the potential of nanotechnology, specifically Calcium Oxide Nanoparticles (CaO NPs) and Graphene Oxide (GO), to ameliorate the negative effects of drought stress on two distinct alfalfa ecotypes. Seeds from Erzurum and Konya regions were regenerated in the Murashige and Skoog (MS) medium, and ensuing callus formation was induced through 1 mg L−1 2,4-D and 1 mg L−1 kinetin MS medium. The callus samples underwent a one-month treatment with varying concentrations of mannitol (50 and 100 mM), CaO NPs, and GO (0.5 and 1.5 ppm). Results revealed a decrease in dry/wet weight with increasing mannitol concentration, contrasting with an increase in weight under CaO NPs and GO treatment. Proline, DNSA, MDA, and H2O2 exhibited proportional increases under drought stress, while CaO NPs and GO treatments mitigated these effects. Physiological and biochemical analyses identified optimal conditions for Erzurum as 50 mM mannitol/2 CaO NPs/0.5 ppm GO, and for Konya as 50 mM mannitol/0.5 ppm GO. Gene expression analysis indicated up-regulation of mtr-miR159 and mtr-miR393 with heightened drought stress, with down-regulation observed in CaO NPs and GO treatments. Scanning Electron Microscopy (SEM) and Confocal Laser Scanning Microscopy (CLSM) confirmed Ca2+ accumulation in alfalfa tissues. In conclusion, CaO NPs and GO treatments exhibited a significant reduction in the adverse effects of drought stress on alfalfa callus under tissue culture conditions. This research sheds light on the potential of nanotechnological interventions to alleviate the impact of environmental stressors on crop plants, opening avenues for sustainable agriculture in the face of changing climatic conditions. Further investigations are warranted to elucidate the underlying mechanisms and scalability of these findings for field applications.

Effect of graphene oxide on CoCrFeNi high-entropy alloy coatings prepared by the electrodeposition method

The performance advantages of high-entropy alloy (HEA) have become a consensus. However, the current preparation methods are mostly focused on thermal processing methods, and the research on the preparation of HEA coatings using electrochemical technology is generally rare. Therefore, in this study, the CoCrFeNi HEA coating was synthesized by electrodeposition technology and the effect of graphene oxide (GO) concentration on the microstructure and tribological property of the HEA coating was further studied. The results showed that during the electrodeposition process, the four atoms of Co, Cr, Fe and Ni were co-deposited to form the HEA coating with a face-centered cubic crystal structure. The introduction of GO did not change the crystal structure of HEA coatings, and GO was also co-deposited with metal atoms to form the HEA-GO composite coating. Meanwhile, GO was distributed in composite coatings in the form of being encapsulated by the metal layer. The addition of GO improved the compactness of HEA coating and reduced the surface roughness. The increase in GO concentration helped to inhibit the formation of the stress-induced cracks on the surface of the composite coating, and significantly enhanced the wear resistance of HEA coating. When the GO concentration was 0.2 g/L, the wear resistance was the best. The wear form of composite coatings was independent of GO and its concentration, and was dominated by abrasive wear.

Effects of Nanoparticles on the Mechanical Properties of the Composites Prepared from Biological and Chemical Gels

Poly (N-isopropyl acrylamide) (PNIPAm) and polyacrylamide (PAAm) are widely used in antifouling research because of their non-harmful nature and their high water-absorbing capacity. In addition, hydrogels such as these two, should be investigated for their mechanical properties because their mechanical properties influence the antifouling paint containing them remaining on the surface of the vessels. In this research PAAm, PNIPAm, and kappa carrageenan (κC) doped with graphene oxide (GO) and multi-walled carbon nanotubes (MWCNTs) composite gels were examined for their mechanical properties for use in antifouling paints as a potential material. For increasing the mechanical properties of composites, GO and MWCNTs are often used as doping materials. In the research described here, a compressive test was used to determine the elasticity, and the modulus was calculated. The toughness was calculated from the slope of the stress-strain curve. The PAAm, PNIPAm, and κC doped with GO and MWCNT exhibited excellent swelling and deswelling behavior and good mechanical properties as composites. The results showed that the composites’ mechanical characteristics increased with an ideal loading concentration of GO and MWCNTs. This study was inspired by our belief of a shortage of research on antifouling materials that are sensitive to the environment. We wanted to create materials that were both effective against fouling and environmentally safe by integrating the beneficial characteristics of hydrogels with potential materials inside antifouling paint. This study, we suggest, is an important step toward the development of antifouling materials with high mechanical performance that are also environmentally friendly.

Layered double hydroxide (LDH)-derived zinc oxide (ZnO) nanorod on exfoliated graphene oxide (GO) nanosheet for photocatalytic dye degradation and hexavalent chromium reduction

A new low-temperature facile chemical decomposition of layered double hydroxide (LDH) has been developed for the large-scale controlled synthesis of zinc oxide (ZnO) nanorod on exfoliated graphene oxide (GO) nanosheet. ZnAl-LDH/GO composite precursor was prepared via in situ growth of the LDH on the exfoliated GO nanosheets. Thermo-chemical decomposition of ZnAl-LDH/GO composite at 80 °C produced highly dispersed ZnO nanorods on GO nanosheets. Although, neat ZnAl-LDH produces ZnO nanoparticle aggregates in the absence of GO. The morphology and properties of ZnO nanorods/GO nanocomposite was studied by X-ray diffraction analysis (XRD), transmission electron microscopy (TEM), UV–vis spectroscopy, Fourier transform infrared spectroscopy (FTIR), and thermogravimetric analysis (TGA). The band gap engineering of the nanocomposite was evaluated by varying GO content. The ZnO/GO nanocomposites materials exhibited excellent photo-catalytic activity towards the degradation of methylene blue (MB) and Cr(VI) reduction under the irradiation of direct sunlight at ambient condition. GO plays a crucial role in the directional growth of nanorods and enhances the photocatalytic activity of ZnO nanorods via the synergistic hole formation and electron transfer effect for the potential remediation of waste water.

3D Bioprinting of Biomimetic Alginate/Gelatin/Chondroitin Sulfate Hydrogel Nanocomposites for Intrinsically Chondrogenic Differentiation of Human Mesenchymal Stem Cells.

3D-printed hydrogel scaffolds biomimicking the extracellular matrix (ECM) are key in cartilage tissue engineering as they can enhance the chondrogenic differentiation of mesenchymal stem cells (MSCs) through the presence of active nanoparticles such as graphene oxide (GO). Here, biomimetic hydrogels were developed by cross-linking alginate, gelatin, and chondroitin sulfate biopolymers in the presence of GO as a bioactive filler, with excellent processability for developing bioactive 3D printed scaffolds and for the bioprinting process. A novel bioink based on our hydrogel with embedded human MSCs presented a cell survival rate near 100% after the 3D bioprinting process. The effects of processing and filler concentration on cell differentiation were further quantitatively evaluated. The nanocomposited hydrogels render high MSC proliferation and viability, exhibiting intrinsic chondroinductive capacity without any exogenous factor when used to print scaffolds or bioprint constructs. The bioactivity depended on the GO concentration, with the best performance at 0.1 mg mL-1. These results were explained by the rational combination of the three biopolymers, with GO nanoparticles having carboxylate and sulfate groups in their structures, therefore, biomimicking the highly negatively charged ECM of cartilage. The bioactivity of this biomaterial and its good processability for 3D printing scaffolds and 3D bioprinting techniques open up a new approach to developing novel biomimetic materials for cartilage repair.

Graphene oxide nanocellulose composite as a highly efficient substrate-free room temperature gas sensor

This study introduces the development of novel, flexible gas sensors operating at room temperature (RT), utilizing a graphene oxide (GO) via the modified Hummers' method and bacterial nanocellulose (BNC) composite to enhance gas detection in industrial and environmental settings. The composite materials, denoted as GO@BNC, were synthesized with varying GO concentrations ranging from 2 % to 30 %, aiming to investigate their responsiveness to gases such as carbon dioxide (CO2), oxygen (O2), acetone (Ac), and ethanol (Eth). The prepared nanomaterials were characterized using FT-IR, Raman, TGA, SEM, and AFM techniques. The bandgap of Go ranges from 4.19, 3.47, 3.16, 2.79, and 2.48 eV for 2, 5, 10, 20, and 30 % GO concentrations, respectively. Notably, the sensor containing wt % of 20 % GO concentration exhibited remarkable sensitivity to Ac, achieving a 270 % increase in resistance at a concentration of 250 μL/L. Conversely, the sensor with a wt % of 30 % GO composition showed superior sensitivity to Eth, with a 420 % signal enhancement under similar conditions. Further modification of GO@BNC through mild reduction resulted in the formation of reduced graphene oxide (rGO@BNC) composites intended to assess the functional groups' impact on sensing performance. Our findings underscore the potential of GO@BNC composites as sustainable and efficient materials for fabricating eco-friendly flexible gas sensors and devices for detecting organic compounds.

Physiological and transcriptomic responses of silkworms to graphene oxide exposure

The growing use of nanomaterials has sparked significant interest in assessing the insect toxicities of nanoparticles. The silkworm, as an economically important insect, serves as a promising model for studying how insects respond to harmful substances. Here, we conducted a comprehensive investigation on the impact of graphene oxide (GO) on silkworms using a combination of physiological and transcriptome analyses. GO can enter the midguts and posterior silk glands of silkworms. High GO concentrations (> 25 mg/L) significantly (P < 0.01) inhibited larval growth. Additionally, GO (> 5 mg/L) significantly reduced the cocooning rate, and GO (> 15 mg/L) hindered oviduct development and egg laying in silkworms. GO increased the reactive oxygen species content and regulated catalase activity, suggesting that it may affect insect growth by regulating reactive oxygen detoxification. The transcriptome data analysis showed that 35 metabolism-related genes and 20 ribosome biogenesis-related genes were differentially expressed in response to GO, and their expression levels were highly correlated. Finally, we propose that a Ribosome biogenesis–Metabolic signaling network is involved in responses to GO. The research provides a new perspective on the molecular responses of insects to GO.

Preparation and Properties of Environmentally Friendly, Hydrophobic, Corrosion-Resistant, Multifunctional Composite Coatings

With the continuous exploitation of the marine resources, the equipment should meet the marine complex working environment. In this study, a type of environmentally friendly coating was prepared. Based on low surface energy environmental protection and anti-fouling, a film forming material with water-based epoxy-modified silicone resin emulsion was prepared. And industrial fillers were added to give it both inorganic and organic properties. Meanwhile, various contents of graphene oxide (GO) were added in the coating system. The coating properties were comprehensively analyzed, and the optimal GO content was obtained as 0.1 wt. %. The composite coating was studied by seawater immersion experiments, and the failure process of the coating in was proposed. The composite coating prepared in the present study has both environmental protection and hydrophobic anti-fouling characteristics, and its comprehensive performance is excellent through various performance evaluations, i.e., it meets the requirements of long-term coating, environmental friendliness and anti-fouling and corrosion resistance.

Exfoliation of Graphite into Graphene Oxide and Reduction by Plant Extract to Synthesize Graphene

Graphene oxide (GO) is a demand material in industrial field for many applications such as electronic devices, capacitor and sensor. This is due to its unique structures and excellent properties. The GO sheets were exfoliated from graphite rod in electrochemical exfoliation. To reduce GO, an electrochemical reduction of GO using green tea was carried out in this research. The conventional chemical reduction method consumed highly toxic and strongly hazardous chemicals such as hydrazine to reduce GO to reduced GO (RGO). Therefore, a green synthesis method was proposed by using green tea leaves extract as the reducing agent to synthesize RGO. Fourier transform infrared (FTIR) spectroscopy and X-ray diffraction (XRD) results show that low amount of oxygen-containing functional groups was remained after green tea reduction due to weak reduction capability by green tea. In addition, EDX indicates that oxygen content of GO was decreased from 23.23 to 16.89 Mass% after green tea reduction.

A physicochemically reformed nanostructured graphene oxide-doped indium magnesium oxide film with enhanced electrical properties

Brush-coated graphene oxide (GO)-doped indium magnesium oxide (InMgO) films were produced in this study. The GO concentration was adjusted to 0, 5, and 15 wt%. The hybrid films were constructed using a one-step facile brush-coating process. The formed hybrid film had an oriented anisotropic morphology with a micro/nanogroove structure due to the shear stress induced by the brush hair movement. This anisotropic structure was used as a liquid crystal (LC) alignment layer. Polarized optical microscopy and pretilt angle analysis revealed the presence of a uniform and homogeneous LC alignment on the hybrid film. The film exhibited excellent light control with the LCs, as well as stable and high optical transmittance in the visible region. The GO doping of InMgO increased its polar anchoring energy and decreased its hysteresis characteristics for LC electronic device applications. These results demonstrate the potential of doping metal oxide films with GO and brush coating them for use in next-generation LC devices.

Evaluation of the mechanical properties and degradation behavior of chitosan-PVA-graphene oxide nanocomposite scaffolds in vitro

ObjectivesChitosan (CTS) has been a popular option for scaffold fabrication because of its biocompatibility, biodegradability, antimicrobial and nonimmunogenic effects. However, it is of limited function, due to its low mechanical strength and its solubility in acidified media. These limitations could be overcome by its blending with PVA and incorporation with bioactive materials to improve its mechanical properties and tissue regeneration capability. MethodsCarbon based nanomaterials, such as graphene oxide (GO) incorporated with CTS/PVA blend to improve composite-scaffold stability. GO nanoparticles were chemically prepared and fully characterized. Different concentrations of both CTS and nano-GO were used for the fabrication of CTS/PVA/GO nanocomposite films through the solvent-casting method. The mechanical properties, thermal stability biodegradation, and swelling of the nanocomposite films were evaluated after characterization by XRD, FTIR and SEM, to detect the effect of GO incorporation in the scaffold to select the suitable dental application. ResultsA better performance was observed in thermal stability, biodegradation, and water resistance after GO addition into CTS/PVA scaffolds. Regarding mechanical properties, groups were assessed by Kruskal Wallis test afterward Dunn’s post hoc test. There was no significant difference in tensile strength between the nanocomposite films of CTS (2%) and CTS (3%). The tensile strength decreased after addition of nano-GO at different concentrations. The elastic modulus significantly increased when (1%) GO was added into the 1CTS (2%):1PVA. ConclusionsCTS/PVA/GO nanocomposite can be used in dental hard tissue engineering, as the incorporation of GO into the CTS/PVA polymer blend improves its properties which is regarded as the critical concentrations of CTS and GO.

The effect of reduced graphene oxide concentration on the wear behaviour of reduced graphene oxide–nickel–boron (Ni–B–rGO) electroless coatings

In this article, the electroless nickel-boron coatings containing different rGO concentrations (0,6, 20.5, 35 and 40 mg/L) were deposited on AISI 4140 steel. Their structural properties were examined using X-ray diffraction, Raman spectroscopy, infrared spectroscopy, scanning electron microscopy and hardness analysis. Moreover, their friction coefficient and wear properties were studied using a pin-on-disc test. The results showed that as the rGO concentration increased, the structure of the coating changed from amorphous to semi-crystalline. Adding rGO up to 20.5 mg/L increased the hardness of the as-plated NiB coating from 519 to 863 Hv and reduced its specific wear rate from 1.28 × 10−9 to 0.68 × 10−9 kg/Nm. However, increasing the rGO concentration to 40 mg/L led to rGO agglomeration and increased the specific wear rate of the coating.