Graphene-based Polymer Nanocomposites Research Articles

Intermolecular interactions in graphene and oxidized graphene nanocomposites

The spatial arrangement of graphene (G) or graphene oxide (GO) nanoplate agglomerations will significantly impact the material properties of graphene-based polymer nanocomposites. Therefore, we investigated the stability of G and GO agglomerates without the presence of a polymer network using molecular dynamics (MD) simulations, which was not considered in our previous work (Reil, 2022) [15]; [16]. G and GO nanoplates, often procured in powder forms, display a significant volume difference by visual observation. To this end, MD simulations were performed to model G or GO agglomerations in the powder form, including the effects of varied plate dimensions and localized surface oxidation. G plates on average released 231 kcal/mol upon agglomerating into aligned stacks, closely matching results in the literature. Simulations of GO resulted in agglomerations of clusters of plates rather than aligned stacks, releasing on average 16 % less energy than G. The clustered arrangement of GO plate agglomerates in simulations occupied a volume approximately 7x that of the aligned stack G plates, closely replicating the experimentally determined volume ratio of 10x. This research could yield further insight into the behavior of G and GO when in the presence of various polymer networks, which could be different than in isolation.

Anti-corrosion and flame-retardant properties of environmentally benign smart functionalized WS2/rGO in epoxy coatings for enhanced steel structural protection in natural seawater

The epoxy matrix (EP) was filled with the rGO-APOD/WS2 nanofiller that was generated through mixing the surface-modified WS2 with reduced graphene oxide (rGO) and 2-amino-5-(4-aminophenyl)− 1, 3-oxadiazole (APOD). The effectiveness of epoxy coating on mild steel as a barrier against various concentrations of rGO-APOD/WS2 in naturally occurring seawater was assessed using EIS, SECM, and salt spray tests. In order to achieve the best coating performance, it was found that the optimal weight ratio of rGO-APOD/WS2 in the EP matrix was 0.3. The limiting oxygen index (LOI) test showed that the rGO-APOD/WS2 considerably enhanced the flame retardancy properties of the epoxy coating. In comparison to pure epoxy coating, the EP-rGO/APOD-WS2 demonstrated better flame retardancy with considerable reductions in the values of PHRR and THR, i.e., 81% and 70%, respectively. It was discovered that the coating resistance of EP-rGO/APOD-WS2 was much higher (Rcoat: 9.89E10 kΩ.cm2) than that of pure matrix (1.49E5 kΩ.cm2) after being exposed to natural seawater for one hour. The EIS experiments showed that the EP-rGO/APOD-WS2 nanocomposite had increased coating resilience even after 200 h of submersion in seawater. Because the coated substrate is more resistant to anodic dissipation than the uncoated substrate, SECM investigations showed that the least quantity of Fe2+ ions discharged at the scratch of the EP-rGO/APOD-WS2 coating. WS2 was found in rusted parts, producing an excellent inert layer at the surface, according to FE-SEM/EDX investigation. The newly created EP-rGO/APOD-WS2 composite has higher barrier and hydrophobic characteristics, according to the results (WCA:162°). The epoxy matrix's mechanical properties were enhanced by the addition of rGO/APOD-WS2. It was discussed how graphene-based polymer nanocomposites might prevent corrosion. As a result, an industrial coating made of the EP-rGO/APOD-WS2 nanocomposite may be used.

Graphite- and Graphene-Based Polymer Nanocomposites for Flexible Sensors and Actuators in Health Care and Soft Robotics Applications

Flexible sensors and actuators have broad applications in the fields of wearable electronics for health, sports, functional textiles, robotics and cobot applications. Graphene-or graphite-based polymer nanocomposites are promising materials for the development of soft sensors and actuators. This study investigates strain sensing properties of silicon rubber with various graphene filler concentrations (8wt%-12wt%). Current-voltage characteristics have been measured under various strains. We obtain that the sensor’s electrical resistance, for a given voltage, can be approximated by a linear fit of the logarithmic resistance as function of the extension ratio of the sensor. The obtained mechanically induced logarithmic resistor behavior of the polymer nanocomposite is highly promising for the development of electronic sensing and control. Furthermore, thin film graphite layers were investigated on highly stretchable silicone membranes.

Investigating the mechanical performance of graphene reinforced polymer nanocomposites via atomistic and continuum simulation approaches

Graphene, having exceptional mechanical properties, is expected to improve the overall mechanical performance of polymer nanocomposites when inserted as a nanofiller. In this work, the mechanical properties of graphene-based cis-1,4-polybutadiene glassy polymer nanocomposites are investigated via a hierarchical multiscale approach, combining atomistic simulations and continuum mechanics. The global mechanical properties of the graphene-based polymer nanocomposites are computed via a rich enough set of remote applied deformations. On a localized level, the effective Young's modulus and Poisson's ratio are calculated in both the interphase and polymer matrix regions where the former shows greater rigidity. Finally, the properties of the different phases forming the heterogeneous polymer nanocomposite are used to develop a continuum three-phase micromechanical finite element model for predicting the overall mechanical behavior of the structure, which are found to be in very good agreement with the results from the atomistic MD simulations.

Mechanism of coupling polymer thickness and interfacial interactions on strength and toughness of non-covalent nacre-inspired graphene nanocomposites

Nanoconfinement resulting from interfacial attraction leads to the formation of polymer interphases with outstanding stiffness, which profoundly impacts the toughness and strength of non-covalent nacre-inspired nanocomposites with “brick-and-mortar” structures. Nonetheless, challenges arise due to discrepancies in interphase thickness characterization and ambiguity in nanoscopic foundations of interfacial stiffening, which hinders systematic understanding of strengthening and toughening mechanisms. To address these issues, we conduct coarse-grained molecular dynamics simulations to investigate the effect of polymer phase thickness and interfacial strength on the toughness and strength of graphene-polyethylene nanocomposites. Our results indicate that when the interfacial adhesion is equal to 0.12 J/m2, nanocomposites possessing a polyethylene phase thickness of 3 nm exhibit significantly greater yield strength (590.8 ± 3.3 MPa) than those of other thicknesses, while nanocomposites with polyethylene phase thickness of 13 nm exhibit the highest toughness (83.3 ± 1.7 MJ/m3). When the interfacial interaction adhesion increases from 0.12 to 1.75 J/m2, both the yield strength and toughness of nanocomposites with polymer thickness 3 nm experience a three-phase increase, reaching up to 1442.3 ± 107.7 MPa and 119.8 ± 8.4 MJ/m3, respectively. The aforementioned improvement in both strength and toughness can be attributed to the nanoconfinement originating from strong interfacial adhesion, which enhances the stiffness and strength of the polymer glues filling the gaps of graphene “bricks”. Furthermore, the deviation of the simulation results from the shear-lag model with mechanical properties of bulk polymer can be remedied with the nanoconfinement effect and polymer stretch taken into account. Our findings provide timely guidance for future design of non-covalent nacre-inspired graphene-based polymer nanocomposites with high toughness and strength.

Graphene-Based Polymer Nanocomposites Preparation and Their Advantages

Graphene and its derivatives have attracted the attention of researchers since its discovery due to its surprising properties. Since then, scientists have been trying to improve the processes that allow the incorporation of this material into polymeric matrices, to improve them, through the development of graphene-based polymeric nanocomposites. This review study reviewed these methods meticulously. Furthermore, it has already been cataloged that adding small amounts of graphene nano-fillers tends to improve the polymers’ mechanical, electrical, and thermal properties.

Thermal Properties of Graphene based Polymer Nanocomposites

Objective: Epoxy is a commonly used material for electronic components packaging, yet its inherent thermal resistance can’t meet rising demands. To improve the thermal performance of Epoxy material, the high thermal conductivity of Graphene nanoparticles interspersed into the epoxy matrix. This paper focuses on experimental results on the thermal properties of Graphene-based epoxy composite. Methods: Scanning Electron Microscopy and Energy Dispersive X-Ray Spectroscopy used for elemental analysis. Guarded Comparative Longitudinal Heat Flow Technique, thermogravimetric analysis, digital scanning calorimeter, and thermogravimetric analysis used to determine thermal conductivity, Coefficient of thermal expansion, specific heat capacity and thermal stability as per ASTM standard respectively. Findings: Thermal decomposition temperature enhanced from 170 0C of pure epoxy to 329 0C for epoxy with 0.5 wt% of Graphene nanofiller, and it increased with an increase in filler loading, hence proving the thermal stability of composite improved with the addition of graphene nanoparticles. Maximum thermal conductivity of 0.43 W/mK and thermal diffusivity of 0.686 x10-6 m2/s had recorded for 2 wt% of Graphene additives. Linear thermal expansion coefficient and specific heat reduce for the composite material with an increase in filler. Therefore, this indicates heat resistivity improved with minimum heat storage. An increase in stability, conductivity, and diffusivity with the decrease in expansion coefficient and specific heat capacity due to heat proves a favourable factor for thermally conductive material. Novelty: The easy method employed for material preparation, also the use of ultra-low filler content tends to reduce composite cost. Graphene-based Epoxy composites with modified properties represent a conceivable packaging material. Keywords: Thermal Properties; Epoxy composites; Specific heat; Thermal conductivity; Thermal diffusivity

Recent Advances in Graphene-Based Nanocomposites for Ammonia Detection.

The increasing demand to mitigate the alarming effects of the emission of ammonia (NH3) on human health and the environment has highlighted the growing attention to the design of reliable and effective sensing technologies using novel materials and unique nanocomposites with tunable functionalities. Among the state-of-the-art ammonia detection materials, graphene-based polymeric nanocomposites have gained significant attention. Despite the ever-increasing number of publications on graphene-based polymeric nanocomposites for ammonia detection, various understandings and information regarding the process, mechanisms, and new material components have not been fully explored. Therefore, this review summarises the recent progress of graphene-based polymeric nanocomposites for ammonia detection. A comprehensive discussion is provided on the various gas sensor designs, including chemiresistive, Quartz Crystal Microbalance (QCM), and Field-Effect Transistor (FET), as well as gas sensors utilising the graphene-based polymer nanocomposites, in addition to highlighting the pros and cons of graphene to enhance the performance of gas sensors. Moreover, the various techniques used to fabricate graphene-based nanocomposites and the numerous polymer electrolytes (e.g., conductive polymeric electrolytes), the ion transport models, and the fabrication and detection mechanisms of ammonia are critically addressed. Finally, a brief outlook on the significant progress, future opportunities, and challenges of graphene-based polymer nanocomposites for the application of ammonia detection are presented.

Modeling of electrical conductivity of graphene-based polymer nanocomposites: calculation from the first principles

The use of nanocomposite materials has led to progress in the creation of new electronic devices (minitransistors, sensors, micro-drives, which are used to build artificial muscles, and supercapacitors. Nanocomposites occupy a special place with magnetosensitive fillers, particularly successfully used in medicine. Nanocomposites are also used for a protective coating. Depending on the operational functions, achieving a specific conductivity value and its change with temperature is necessary for such a coating. In the work, a conductivity model of polymer nanocomposites based on graphene (Gr/PS) was obtained using experimental data. The largest relative deviation between the conductivity surface and experimental data does not exceed 9.5%. The expression was obtained for the graphene concentration 1 < C(Gr) < 30 wt % and the temperature range 20 < T < 100 °C. The dependence of the specific electrical conductivity on the filler concentration and temperature obtained in the work will allow the researchers to select a nanocomposite with the required conductivity and evaluate the temperature effects on it for the conditions to which the material will be exposed.

Synthesis and applications of graphene and graphene-based nanocomposites: Conventional to artificial intelligence approaches

Recent advances in graphene research have enabled the utilization of its nanocomposites for numerous energy-based and environmental applications. Recently, the advancement in graphene-based polymer nanocomposites has received much attention with special emphasis on synthesis and application. Graphene-based nanocomposites show astonishing electrical, mechanical, chemical, and thermal characteristics. Graphene nanocomposites (GNCs) are synthesized using a variety of methods, including covalent and non-covalent methods, a chemical-based deposition approach, hydrothermal growth, electrophoresis deposition, and physical deposition. Chemical methods are the most viable route for producing graphene in small quantities at low temperatures. The technique can also produce graphene films on a variety of substrate materials. The use of artificial intelligence (AI) for the synthesis of AI-created nanoparticles has recently received a lot of attention. These nanocomposite materials have excellent applications in the environmental, energy, and agricultural sectors. Due to high carrier mobility, graphene-based materials enhance the photocatalytic performance of semiconductor materials. Similarly, these materials have high potential for pollutant removal, especially heavy metals, due to their high surface area. This article highlights the synthesis of graphene-based nanocomposites with special reference to harnessing the power of modern AI tools to better understand GNC material properties and the way this knowledge can be used for its better applications in the development of a sustainable future.

Graphene-based polymer nanocomposites in food packaging and factors affecting the behaviour of graphene-based materials: a review

Graphene-based polymer nanocomposites in food packaging and factors affecting the behaviour of graphene-based materials: a review

Synthesis of Graphene-based Polymer Nanocomposites and comparison of properties

Biodegradable polymers promise a more sustainable future. Among a wide range of biopolymers utilized, Poly Lactic Acid (PLA) possess better biomechanical and functional characteristics and is used in various level of applications. However, to have better suitability for biomedical applications, it is necessary to enhance the overall performance of PLA such as biodegradability, porosity, and mechanical properties. Reinforcement of the matrix material with nanofiller is a commonly used method to achieve this. Graphene is the most versatile material with exotic mechanical, electrical, and thermal properties. Its combination with polymers can create wonders. Graphene-based polymer composites exhibit potential use in various fields that include energy storage, biomedical use, and environmental applications. In this work, nanocomposites of PLA with graphene derivatives like Graphene Oxide (GO) and reduced Graphene Oxide (rGO) were fabricated by the solvent casting method. The composites' biological and mechanical properties were investigated and compared. Results demonstrate that the incorporation of GO and rGO enhanced the properties of PLA. The mechanical parameters of the composites with rGO were higher than those of the composites with GO in terms of tensile strength and Young's modulus. A reduction in elongation at break was observed for composites reinforced with rGO. PLA/rGO composites exhibit higher mechanical and biological properties than PLA/GO composites. The developed nanocomposite will be a promising competitor in the research arena with potential applications.

Fabrication and Model Characterization of the Electrical Conductivity of PVA/PPy/rGO Nanocomposite.

Owing to the numerous advantages of graphene-based polymer nanocomposite, this study is focused on the fabrication of the hybrid of polyvinyl alcohol (PVA), polypyrrole (PPy), and reduced graphene-oxide. The study primarily carried out the experimentation and the mathematical analysis of the electrical conductivity of PVA/PPy/rGO nanocomposite. The preparation method involves solvent/drying blending method. Scanning electron microscopy was used to observe the morphology of the nanocomposite. The electrical conductivity of the fabricated PVA/PPy/rGO nanocomposite was investigated by varying the content of PPy/rGO on PVA. From the result obtained, it was observed that at about 0.4 (wt%) of the filler content, the nanocomposite experienced continuous conduction. In addition, Ondracek, Dalmas s-shape, dose–response, and Gaussian fitting models were engaged for the analysis of the electrical transport property of the nanocomposite. The models were validated by comparing their predictions with the experimental measurements. The results obtained showed consistency with the experimental data. Moreover, this study confirmed that the electrical conductivity of polymer-composite largely depends on the weight fraction of fillers. By considering the flexibility, simplicity, and versatility of the studied models, this study suggests their deployment for the optimal characterization/simulation tools for the prediction of the electrical conductivity of polymer-composites.

Trade-off between interface stiffening and Young's modulus weakening in graphene/PMMA nanocomposites

Mechanical performance of graphene-based polymer nanocomposites is reported to be far below theoretical predictions. A critical factor lies in the weak bonding of graphene/polymer interfaces. Chemical functionalization is deemed as a common strategy to improve the interfacial adhesion between graphene and polymer, however, the creation of structural defects in graphene lattice is inevitable during such a chemical process. It hence calls for a balance in the design of graphene-based nanocomposites between the interface strengthening and mechanical degradation of graphene itself. Herein, mechanically exfoliated monolayer graphene is oxidized and atomic force microscopy (AFM) is performed to quantify the dependence of Young's modulus of graphene on the functionalization degree. In situ tensile-micro Raman spectroscopy is utilized to measure the interfacial properties between functionalized graphene and poly (methyl methacrylate) (PMMA) at the microscopic level. An optimal functionalization degree is determined to maximize the reinforcing effect of nanocomposites. Our results will be helpful to design various nanofiller-based composites with high mechanical performance.

Recent Trends in Graphene/Polymer Nanocomposites for Sensing Devices: Synthesis and Applications in Environmental and Human Health Monitoring

Graphene-based nanocomposites are largely explored for the development of sensing devices due to the excellent electrical and mechanical properties of graphene. These properties, in addition to its large specific surface area, make graphene attractive for a wide range of chemical functionalization and immobilization of (bio)molecules. Several techniques based on both top-down and bottom-up approaches are available for the fabrication of graphene fillers in pristine and functionalized forms. These fillers can be further modified to enhance their integration with polymeric matrices and substrates and to tailor the sensing efficiency of the overall nanocomposite material. In this review article, we summarize recent trends in the design and fabrication of graphene/polymer nanocomposites (GPNs) with sensing properties that can be successfully applied in environmental and human health monitoring. Functional GPNs with sensing ability towards gas molecules, humidity, and ultraviolet radiation can be generated using graphene nanosheets decorated with metallic or metal oxide nanoparticles. These nanocomposites were shown to be effective in the detection of ammonia, benzene/toluene gases, and water vapor in the environment. In addition, biological analytes with broad implications for human health, such as nucleic bases or viral genes, can also be detected using sensitive, graphene-based polymer nanocomposites. Here, the role of the biomolecules that are immobilized on the graphene nanomaterial as target for sensing is reviewed.

Recent Advances in Graphene-Based Polymer Nanocomposites and Foams for Electromagnetic Interference Shielding Applications

Recent Advances in Graphene-Based Polymer Nanocomposites and Foams for Electromagnetic Interference Shielding Applications

Effects of Graphene Oxidation on Interaction Energy and Interfacial Thermal Conductivity of Polymer Nanocomposite: A Molecular Dynamics Approach.

Interfacial characteristics of polymer nanocomposites represent a crucial aspect to understand their global properties and to evaluate the interaction between nanofillers and matrix. In this work we used a molecular dynamics (MD) approach to characterize the interfacial region at the atomistic scale of graphene-based polymer nanocomposites. Three different polymer matrixes were considered, polylactic acid (PLA), polypropylene (PP) and epoxy resin (EPO), which were reinforced with three types of graphene fillers: pristine graphene (G), graphene oxide (GO) and reduced graphene oxide (rGO). In particular, the compatibility of the nanofillers in polymer matrixes were evaluated in terms of the interaction energy, while the interfacial thermal resistance (Kapitza resistance) between matrices and fillers was calculated with a nonequilibrium molecular dynamics (NEMD) method. Results showed that the oxidation degree plays an important role on the studied properties of the interfacial region. In particular, it was observed that the Kapitza resistance is decreased in the oxidized graphene (GO and rGO), while interaction energy depended on the polarity of the polymer matrix molecules and the contribution of the Coulombic component.

ПОЛУЧЕНИЕ ГРАФЕНОВЫХ СТРУКТУР И НАНОПОЛИМЕРОВ С ИСПОЛЬЗОВАНИЕМ УЛЬТРАЗВУКОВЫХ КОЛЕБАНИЙ

Graphene-based polymer nanocomposites are considered a promising class of future materials. The degree of filling, the filler and binder nature, and the shape, size, and mutual arrangement of filler particles determine the properties of a polymer composite material. The destruction of nanoparticles aggregates occurs most effectively in liquid media under the action of ultrasonic vibrations. The authors proposed the technique and designed laboratory equipment for ultrasonic treatment of the finely-dispersed graphite suspension, carried out the ultrasonic treatment (UST) of finely-dispersed graphite powder. The suspensions based on graphite with a solvent were obtained. The authors carried out the experiments on producing graphene using the graphite liquid-phase exfoliation method at the ultrasonic treatment with different ultrasonic treatment times, analyzed experimental data, and selected the UST optimal time. The paper contains the results of the study of the effect of the graphite suspension base on the degree of ultrasonic liquid-phase exfoliation of graphite. The most effective synthesis of graphene structures using UST is synthesis from graphite suspensions based on dichloroethane, benzol, and dichlorobenzene. Graphene structures’ output ratio amounts to up to 66 %. The authors developed the technology for producing polymers modified with graphene structures using ultrasonic dispersion. Based on graphene synthesized by the graphite liquid-phase exfoliation, the authors obtained nanopolymers using ultrasonic vibrations, carried out DSC measurements, and studied their strength properties. The limit strength of elastic polymers is from 1.9 to 3.6 MPa at different concentrations of graphene inclusions. The residual elongation of samples within the deviation did not change and amounted to 200 %.

The Effect of Graphene Oxide Dispersion on Structure-Property Relationships in Graphene-Based Polymer Nanocomposites

The performance of graphene/polymer nanocomposites depends on many factors but the major factor is a nanoparticles dispersion and distribution into the host matrix. The present work investigates the effect of the dispersion of graphene oxide upon the structure-property relations in metallocene linear low density polyethylene (PE), homo polypropylene (PP), and blends thereof. These nanocomposites were prepared by solvent processing, where DMF and o-xylene were used as solvents for Graphene Oxide (GO) powder and the polymers respectively, before the two components were combined to form a well-mixed initial state. Characterization of the structure and crystallization of the nanocomposites was carried out by small- and wide-angle X-ray scattering and diffraction (SAXS and WAXD). The chemical structures were characterized by Fourier transform infrared spectroscopy (FTIR) and by Raman spectroscopy, and the latter used to calculate the ID/IG value for a pure GO samples. The thermal properties of the resulting nanocomposites were investigated by DSC and TGA in order to obtain Melting temperature ( ), crystallization temperature ( ) and degree of crystallinity ( ) as well as a range of degradation temperatures. The effect of GO on the mechanical properties was studied via the ultimate tensile strength and elastic modulus.

Thermal and morphological study of graphene based polyurethane composites

Graphene-based polymer nanocomposites are highly used in the field of membranes, biomedical aids, automotive, electronics, actuators, aerospace and sensors. In this paper, the thermal and morphological study of polyurethane nanocomposites was carried out. Polyurethane nanocomposites were fabricated using the melt mixing in the presence of a solvent. Different weight percentages of graphene (2.5 wt%, 5 wt%, and 10 wt%) were incorporated for preparing the nanocomposites. The morphological study of the polyurethane and nanocomposites samples was explored by scanning electron microscope (SEM) to observe the dispersion of graphene nanomaterials in the polyurethane matrix. Fourier Transform Infrared Spectroscopy (FTIR) was applied to examine the chemical properties of the different polyurethane nanocomposite. The existence of graphene in the polyurethane matrix was studied using X-ray diffraction (XRD). The thermal analysis of the nanocomposite samples was analyzed using Thermogravimetric analysis (TGA). SEM showed that the graphene is dispersed throughout the polyurethane matrix. FTIR investigation showed that there is no change in the chemical properties of the polyurethane with the addition of graphene. XRD technique confirms the existence of graphene in the polyurethane matrix. TGA analysis concluded that the integration of graphene in the polyurethane matrix increases the thermal stability property of polyurethane. Therefore, as a result of the current study, polyurethane nanocomposites can be fabricated without any changes in chemical properties.