Graphene Nanoplatelets Content Research Articles

Effect of Graphene Addition on Microstructure and Mechanical Properties of Cast Aluminium Alloy Composite

Aluminium-reinforced metal matrix composites (Al-MMCs) are highly desirable because of their low density, excellent corrosion resistance, high thermal and electrical conductivity, high strength, and stiffness. This research intends to improve the mechanical properties of Al-MMCs for lightweight automotive and aerospace applications. A Taguchi method with two parameters and four levels was used to determine the optimum amounts of graphene nanoplatelets (GNPs) (0.1, 0.25, 0.5, and 0.6 wt%) and stirring duration (1, 2, 4, and 8 minutes). GNPs were added to the molten aluminium alloys through the stir-casting process to enhance the mechanical properties of the Al-MMCs. The results revealed that the Al-MMCs with 0.25 wt% GNPs and 8 minutes of stirring time produced the highest value of hardness and tensile properties. Under these parameters, the microstructure changed from dendritic to rosette, which had a tremendous effect on the improvement of the mechanical properties. The Ultimate Tensile Strength (UTS) and Yield Strength (YS) of the samples were improved after T6 heat treatment with a value of 210.26 MPa and 145.31 MPa, respectively, and the hardness was 116 HV while the elongation to fracture was 4.89%. The results showed that the high GNP concentration improved the mechanical properties of the Al-MMCs.

Theoretical study on electrochemical and thermal behavior of GNP incorporated anode materials for lithium-ion batteries

In this paper, a theoretical investigation of the electrical and thermal performance of lithium-ion batteries employing an unexplored graphene nanoplatelets (GNP) incorporated lithium titanate (LTO-GNP) anode and lithium manganese oxide cathode is demonstrated by using the COMSOL Multiphysics modeling and simulation. The GNP proportions in the LTO active material matrix are varied from 0 to 3 wt%, to assess the improvements in cell potential, state of charge (SOC), variation in internal temperature, discharging capacity, and battery power density across four selected electrodes. The simulation results have indicated the positive effects of increasing the anode’s GNP concentration on the battery performance, alongside temperature-dependent open-circuit voltage (OCV) and SOC outputs of the battery. The analysis of the effects of thermal conductivity on heat accumulation and dissipation within the battery has indicated that the anode with 3 wt% of GNP consistently performed superior to the other electrodes by providing uniform temperature distribution and enhanced electrical performance by promoting better discharge capacity and power density. The LTO anode with 3 wt% GNP has shown 0.2V more cell potential and also has 12.5% improved thermal conductivity when compared to LTO anode without GNP, contributing to better heat distribution inside the battery. The simulation also emphasized the importance of optimal GNP loading in the Li-ion battery anode to attain more uniform temperature distribution with improved battery health and efficiency.

Recovered graphene-hydrogel nanocomposites for multi-modal human motion recognition via optimized triboelectrification and machine learning

Hydrogels have extensive applications in portable, flexible, wearable, and self-powered electronic devices based on triboelectric nanogenerators (TENGs). An important issue with hydrogels is their tendency to dehydrate over time, which leads to a decline in both ionic conductivity and mechanical flexibility. Furthermore, the current techniques used to produce these hydrogels mostly rely on the freeze–thaw process, which has limited ability to modify the polymer conformation. Herein, a novel water-assisted recovered hydrogel is proposed using a simple strategy to prepare high-performance hydrogel-based TENGs by optimizing the cross-linking and crystalline domains. Synthesis of the electrostatic electrode in the TENG involved the incorporation of polyethylene oxide (PEO) into a polyvinyl alcohol (PVA) hydrogel network via cross-linking. Graphene nanoplatelets (GNP) were added to precisely tune the electrical conductivity. GNP constructs the backbone structures in the hydrogel and enhances the charge transport capacity. Electrical conductivity is changed by the GNP concentration and thus, electrical output of the hydrogel can be facilely controlled. The water reabsorption increased density and crystallinity of the cross-linking and allowed the hydrogel to show superior performance compared to the original one. The 7th recovery hydrogel produced around 594 V, 40 μA, and 32 nC. The 7th recovery hydrogel had exceptional endurance, with the capacity to withstand over 16,000 cycles of contact separation. Moreover, it could be stretched up to 541 % of its original length and improved by almost twice as much as that without the recovery process. By combining multi-modal graphene-based TENG sensors with machine learning, a state-of-the-art behavioral monitoring system was created that could reliably detect tapping fingers with an average accuracy rate of 95 %. The findings of this research will pave the way for new approaches to the development of autonomous motion sensors and flexible renewable energy sources.

Influence of processing method on the conductive properties of nanocomposite films based on nanocellulose and graphene nanoplatelets

The need for improvements in electronic devices has been generating important demands in the technical-scientific area. Thus, including in these devices natural materials, which present desirable performance and are sustainably obtained from renewable sources, becomes an interesting option. Nanocellulose and graphene-based films have been researched for some years seeking to achieve special electrical properties. However, the production method of these films directly influences their electrical properties. In this context, this work proposes to explore the conductive and morphological properties of nanocellulose films combined with graphene nanoplatelets (GNP), produced by two different methods (casting and dip coating). For this, the nanocelluloses were obtained through the milling process in a defibrillator stone mill of eucalyptus cellulose bleached in distilled water. The casting films were produced from the incorporation of GNP directly into the nanocellulose suspension; while the dip coating films were produced from the immersion (5–10 layers) of dry nanocellulose films in a solution containing GNP. In this way, it was sought to compare the nanoplatelets embedded (casting method) within the film to those applied on the external surface of the film (dip coating method). The volumetric conductivity was measured (ASTM D257-07 standard) and the surface conductivity (4-point device) of the films produced. The results showed that all films containing GNP had higher conductivities than pure nanocellulose films. However, casting films, despite having a higher GNP concentration, presented lower volumetric and surface conductivity values when compared to dip coating films. In addition, reassess after 1 year, the dip coating films showed an insignificant decrease in conductivity values, indicating a longer useful life. However, the casting films show about 50% decrease in conductivity. Thus, it was concluded that the presence of GNP only in the outer layer of nanocellulose films is more efficient for potential application in electronic systems.

Hyperelastic model for nonlinear elastic deformations of graphene-based polymer nanocomposites

Graphene-based polymer nanocomposites (PNCs) are increasingly important in engineering applications involving large deformations. However, the nonlinear behavior of these materials has not been thoroughly studied. Current models do not address the specific nonlinear effects of graphene nanofillers under large strains, lack sufficient comparison with experimental data, and primarily focus on uniaxial behavior without exploring biaxial responses, which are relevant in technological applications. This study investigates PNCs composed of silicone elastomer and graphene nanoplatelets (GNPs). We present experimental tests conducted in both simple tension and biaxial inflation on circular membranes. A homogenized hyperelastic model is developed, incorporating distinct contributions from the matrix and the nanofiller. Specifically, we introduce a novel strain energy function for the nanofiller contribution, tailored to reproduce the observed experimental behavior. The model accurately predicts the nonlinear elastic response of the studied PNCs across varying contents of GNPs. The proposed strain energy function is implemented in MATLAB to obtain an exact numerical solution for the inflation of circular PNC membranes. Finally, to demonstrate its broader applicability, the hyperelastic model is applied to additional experimental data from other PNCs found in the literature. This model contributes to establishing a robust framework for the effective use of PNCs.

Utilizing Binary Phase Segregation and Extrusion to Enhance the Electronic Properties of Graphene Nanocomposites.

Our goal in this study is to incorporate graphene nanoplatelets (GNPs) in a polymer blend of poly(lactic acid) (PLA) and isotactic polypropylene (iPP) to facilitate the dispersion of GNPs and use the morphology of phase segregation to create a pathway for concentrating GNPs to achieve percolation with lower GNP concentration. Investigating the interfacial properties between PLA/GNPs and iPP/GNPs, we noticed that iPP has a lower contact angle on GNPs compared to PLA on GNPs. This showed a great potential that the GNP are easily confined in iPP rather than in PLA domains or at the PLA/PP interfaces. Utilizing this property, as the PLA content increases, the iPP content decreases, resulting in a reduction of the available space for GNPs. This decrease in space leads to a higher chance for GNPs to accumulate together. Furthermore, through careful control of the concentration in the immiscible blend of PLA/PP, it is possible to achieve a bicontinuous structure. This structure facilitates the creation of a pathway for the fillers, allowing for the use of minimal GNPs while achieving optimal electrical conductivity properties. The PLA/PP/GNPs can be oriented by the shear forces coming from the nozzle that produce a higher performance.

Infrared on-site heating for material extrusion additive manufacturing of carbon fiber filled polyphenylene sulfide and its nano-graphene-reinforced alternatives

This study investigates the impact of infrared heating and annealing on the mechanical properties of carbon fiber-reinforced polyphenylene sulfide (CF-PPS) and graphene nanoplatelet (GNP)-reinforced CF-PPS composites in Material extrusion (MEX) additive manufacturing. GNP/CF-PPS composites are prepared by mechanically mixing CF-PPS plastic particles with GNP particles and subjecting them to infrared heating and annealing treatments during the three-dimensional (3D) printing process. Three-point bending tests assess the mechanical properties of the samples. The results reveal that the 0.03 wt.% GNP/CF-PPS sample, subjected to infrared heating followed by annealing, exhibits a 30% increase in bending strength compared to pure CF-PPS, demonstrating that the combined treatment significantly enhances mechanical performance. Microscopy observations using a Keyence VH7000 digital optical microscope and a scanning electron microscope (SEM) confirm that GNP addition and infrared irradiation lead to reduced surface roughness and fewer fracture cross-sectional pores. The interlayer bonding improves notably, indicating enhanced internal density and structural stability. Furthermore, differential scanning calorimetry analysis shows a 20% increase in crystallinity for heat-treated samples, contributing to better interlaminar bonding and reduced temperature gradients during printing. Finite element simulations using MATLAB and ABAQUS software corroborate these findings, demonstrating that infrared heating proves more effective than varying GNP content alone in reducing deformation, residual stress, and temperature differences during the MEX process. These results provide valuable insights into improving the mechanical properties and stability of MEX-manufactured large-dimensional composite materials through optimized thermal management.

Transport and magnetic properties of [formula omitted]/Graphene nanoplatelets nanocomposites

A series of Zn0.5Co0.25Cu0.25Ho0.037Fe1.963O4 (ZCCHF)/Graphene nanoplatelets (GNPs) nanocomposites (where GNPs = 0 wt%, 1.25 wt%, 2.5 wt%, 3.75 wt%, 5 wt%) were prepared via sol-gel auto-combustion (SGAC) method followed by bath sonication and studied their structural, morphological, optical, dielectric, and magnetic properties. The structural analysis confirmed a single-phase crystal matrix of all the as-prepared nanocomposites. The optical analysis revealed that the energy bandgap (Eg) lies within the range of 1.57 eV–1.62 eV. The dielectric analysis showed that the improvement in the dielectric constant (ε′) and reduction in dielectric tangent loss (tan δd) with increasing GNPs concentration from 0 wt% to 5 wt%. The real part of permeability (μ′) was improved and magnetic tangent loss (tan δM) was reduced with the addition of GNPs. Magnetic properties were studied at different temperatures (5 K, 300 K, and 400 K), and observed high saturation magnetization (MS), and coercivity (HC) at a low temperature (at 5 K). The low MS, and HC values were observed at high temperatures (300 K and 400 K). The combination of improved dielectric and tunable magnetic properties makes ZCCHF/GNPs nanocomposites promising candidates for applications in spintronics, high-frequency magnetic devices, and advanced electronic systems.

Dielectric, low‐frequency noise and mechanical properties of hybrid carbon nanotubes/graphene nanoplatelets epoxy composites

AbstractThis study analyzes the electrical, microwave (26–37 GHz), low‐frequency (20 Hz–10 kHz) noise, and mechanical properties of epoxy hybrid composites filled with multi‐walled carbon nanotubes (MWCNT) and graphene nanoplatelets (GNP). The system's percolation threshold was around 0.25 vol.% MWCNT, while the electromagnetic properties were almost independent of GNP concentration. The composites are shown to be suitable for electromagnetic shielding in the 26–37 GHz range, with microwave absorption increasing as the total nanocarbon concentration rises. The electrical transport in these composites is governed by one‐dimensional Mott hopping at low temperatures (below 245 K) and redistribution effects above room temperature. The low‐frequency voltage noise spectra of the composites are predominant of the 1/f component, with noise spectral density proportional to Ub, where the exponent b is close to 2, indicating noise caused by resistance fluctuations. The optimal electromagnetic properties are near 0.5 vol.% MWCNT and 0.25 vol.% GNP concentrations. The tensile elastic modulus and yield strength showed the highest increases at 0.25/0.25 loading, with gains of 40.43% and 16.77%, respectively, compared to neat epoxy. Fracture toughness and energy release rate increased with adding 0.25 vol.% GNP, while Charpy impact strength improved with higher MWCNT loading.Highlights Percolation threshold in hybrid MWCNT/GNP composites is close to 0.25 vol.% MWCNT Low‐frequency voltage noise spectra of the composites are 1/f type

Impact of Soybean Biodiesel Blends with Mixed Graphene Nanoparticles on Compression Ignition Engine Performance and Emission: An Experimental and ANN Analysis

The extensive use of fuels in power generation plants, industries, and transportation has led to a scarcity of fossil fuels and has contributed to global warming. This has prompted researchers to focus on improving internal combustion engine performance, as the transportation system accounts for 50% of global fuel consumption. Soybean biodiesel plays a vital role in reducing emissions and fuel consumption in engines. In the current work, a blend of soybean oil is used as a biodiesel (B20, B40, and B60), with and without the addition of graphene nanoplatelets (GNPs) examined on a constant-speed compression ignition (CI) engine with respect to pure diesel. The blends are denoted as B20GNP10, B20GNP20, B20GNP40, B20GNP60, B20GNP80, and B20GNP100, according to their proposition of biodiesel and graphene nanoplatelets. Similar blends were prepared for B40 and B60 combinations with similar GNPs concentrations. The prepared blend properties were measured, and good thermophysical properties were found. The trial includes testing the engine emissions and performance at altering loads ranging from 0 to 12 kg for all blends. The artificial neural network (ANN) tool is used to forecast the accuracy of experimental results. Compared to pure diesel, the B60GNP100 blend at 12 kg load condition showed the lowest brake specific fuel consumption at 12.58 % and the highest brake thermal efficiency at 27.13%. Emissions were estimated using a gas analyzer, and the outcomes indicated that the biodiesel blends have controlled levels of CO, CO2, NOx, and HC compared to pure diesel. The ANN model with 99.99% accuracy was developed using experimental data, confirming the accuracy of the experimental results with lower simulation time and cost. Additionally, the B60GNP100 blend yielded better results compared to previous studies.

Effect of graphene on mechanical and anti-corrosion properties of TiO2-SiO2 sol-gel coating

PurposeThis paper aims to explore how graphene can improve the mechanical and anti-corrosion properties of TiO2-SiO2 sol-gel coating. This sol-gel coating has been prepared on aluminum alloy substrate using graphene as both nano-filler and corrosion inhibitor.Design/methodology/approachTo examine the effect of graphene on mechanical properties of sol-gel coating, the abrasion resistance, adhesion strength and scratch resistance of coating have been evaluated. To reveal the effect of graphene on the anti-corrosion property of coating for aluminum alloy, the electrochemical impedance spectroscopy (EIS) has been conducted in 3.5 Wt.% NaCl medium.FindingsScanning electron microscopy images indicate that graphene nanoplatelets (GNPs) have been homogeneously dispersed into the sol-gel coating matrices (at the contents from 0.1 to 0.5 Wt.%). Mechanical tests of coatings indicate that the graphene content of 0.5 Wt.% provides highest values of adhesion strength (1.48 MPa), scratch resistance (850 N) and abrasion strength (812 L./mil.) for the sol-gel coating. The EIS data show that the higher content of GNPs improve both R1 (coating) and R2 (coating/Al interface) resistances. In addition to enhancing the coating barrier performance (graphene acts as nanofiller/nano-reinforcer for coating matrix), other mechanism can be at work to account for the role of the graphene inhibitor in improving the anticorrosive performance at the coating/Al interface.Originality/valueApplication of graphene-based sol-gel coating for protection of aluminum and its alloy is very promising.

The use of graphene nanoplatelets for enhancement of the compressive strength of mortar containing high-levels of natural Pozzolan

High Pozzolan concrete has an extended setting time and inhibits early-age compressive strength development, which can cause construction delays and limit its application in the concrete industry. The main aim of this study is to evaluate the effectiveness of graphene nanoplatelets (GNPs) in enhancing the mechanical properties of mortar containing high levels of natural Pozzolan. In the beginning, a relatively simple ultrasonication treatment process produced an almost uniform dispersion of GNPs in the mixing water to avoid agglomeration which limits the efficiency of GNPs. Tests on engineering properties indicated that the compressive strength of mortar containing 40 and 60 % natural Pozzolan as a partial replacement of cement was enhanced with the addition of the optimum content of graphene nanoplatelets which was found to be 0.03 % and 0.01 % by weight of binder at 40 % and 60 % cement replacement levels, respectively. The compressive strength was enhanced by 29.6 %, 27.4 %, and 27.5 % at 40 % cement replacement level, and by 86.3 %, 23.7 %, and 25.8 % at 60 % cement replacement level at 7, 28, and 56 days of curing, respectively. SEM investigations indicated that the addition of GNPs densified the structure thus enhancing the performance of mortar.

Rheological, mechanical, and environmental performance of printable graphene-enhanced cementitious composites with limestone and calcined clay

As extrusion-based 3D concrete printing gains wider acceptance in construction, there is a growing imperative to incorporate supplementary cementitious materials (SCMs) into printable mixtures to address their high cement content and promote sustainability. Conventional SCMs like fly ash and slag are becoming increasingly scarce, underscoring the need for alternative solutions such as limestone and calcined clay. Additionally, the utilization of nanomaterials in printable mixtures holds potential for enhancing the mechanical properties of 3D printed structures. These properties are often compromised by interlayer interfaces and void formations during printing, resulting in lower mechanical performance compared to conventionally cast concrete. Graphene nanoplatelets (GNPs), with their high aspect ratios and exceptional mechanical characteristics, offer promising avenues for reinforcing printable cementitious composites. This study explores the rheological, mechanical, and environmental aspects of graphene-enhanced cementitious composites incorporating limestone and calcined clay. Graphene nanoplatelets (GNPs) were dispersed utilizing a surfactant-assisted sonication technique, and their dispersion characteristics were evaluated through absorbance, particle size, and zeta potential measurements. Then, the influence of varying GNP concentrations on the rheological properties of limestone-calcined clay (LC2) cementitious composites was assessed. Compressive and flexural strength tests were conducted on 3D-printed LC2 samples with different GNP ratios, alongside cast specimens for comparison. Microstructural examination of failed specimens was performed using scanning electron microscopy. Furthermore, a life cycle assessment was conducted to compare the environmental impacts of printable LC2 mixtures to conventional printable mixtures. Incorporating GNPs at a ratio of 0.05 % by weight of cement in printable LC2 mixtures enhances compressive strength by 23 %, leading to a reduction of approximately 31 % in environmental impacts compared to conventional printed mixtures.

Interfacial bonding mechanism of graphene nanoplatelets reinforced AZ91D magnesium alloy prepared by semi-solid injection molding

The incompatibility between the strength and thermal conductivity of magnesium alloys limits their application in heat dissipation components. Magnesium matrix composites were obtained by adding reinforcements into the AZ91D alloy to achieve synergistic enhancement of mechanical and thermal conductivity to promote the application of magnesium alloy. Graphene nanoplatelets (GNPs) reinforced magnesium matrix composites were successfully prepared by semi-solid injection molding. The high viscosity of the semi-solid metal slurry contributes to the homogeneous dispersion of GNPs in the magnesium matrix. A GNPs/MgO/Mg heterostructure with high interfacial bonding strength was found at the interface of GNPs and α-Mg matrix. The semi-solid casting method improves the mechanical properties of the composites by grain refinement and simultaneously reduces the thermal conductivity. The addition of GNPs can balance the mechanical and thermal conductivity enhancement, and the most balanced properties of the composites are obtained when the content of GNPs is 0.3 wt%, with a tensile strength of 243.1 MPa, Vickers hardness of 93.7 HV, and thermal conductivity of 74.8 W/(m·K). Therefore, the semi-solid forming method is considered a promising processing method, and GNPs is considered an ideal reinforcement material to improve the performance of the magnesium matrix.

Failure investigation of woven scarf-repaired laminates reinforced with nanoparticles: Experimental and numerical investigations

This study explores the efficacy of multi-walled carbon nanotubes (MWCNTs) and graphene nanoplatelets (GNPs) as nano-reinforcement for the epoxy adhesive layer in scarf joints and 3D scarf-repaired laminates subjected to tensile loading. Experimental characterization of pure epoxy and nanocomposite mechanical properties was validated using the Mori–Tanaka method (incorporating agglomeration effects). A 3D finite element model considering material non-linearity and strain-based damage was employed to investigate joint failure behaviour, validated for 0.5 vol% MWCNT and GNP concentrations. A subsequent parametric study explored the influence of scarf angle, nanoparticle concentration, and patch configuration on 3D repaired specimens. The results suggest a 2.86° scarf angle with a [(+45/−45)]4s patch configuration reinforced with 1 vol% MWCNTs and 0.5 vol% GNPs exhibits the highest tensile strength improvement.

Tribological manufacturing of ZDDP tribofilms functionalised by graphene nanoplatelets

Abstract 3D Tribo-Nanoprinting (3D TNP), which uses a highly controllable tribological contact to deposit tribofilms, has been proposed as a manufacturing method for nanoscale structures. Inspired by this, we show for the first time, as a proof of concept, the ability to electrically functionalise tribofilms for potential use in the manufacture of structures with nanoscale thickness. Zinc dialkyldithiophosphate (ZDDP) tribofilms have been generated to include varying concentrations of graphene nanoplatelets (GNPs) resulting in them becoming electrically conductive when tested using conductive atomic force microscopy. In its highest GNP concentration, approximately 55% of the surface of the tribofilm was able to sustain current up to a threshold of 245 pA. The higher graphene content led to a suppression in film formation and decreased substrate coverage. Transmission electron microscopy revealed a dual-layered tribofilm with a carbon-rich layer above a pure layer of ZDDP tribofilm. Within the carbon-rich layer, the GNPs formed into scrolls which created an internal network through which current could flow, being limited by the insulating pure ZDDP layer at the film-substrate interface, and the presence of surface graphene sheets. A modified lateral force microscopy procedure supported the presence of surface graphene sheets. Despite limited deposition precision in terms of homogeneity and distribution of the tribofilms, this work provides a step towards the use of 3D TNP for the manufacture of electronic structures on the nanoscale by proving that tribofilms can be functionalised by the addition of particle additives.

EXPERIMENTAL INVESTIGATION OF AMINE-BASED GRAPHENE NANOSUSPENSION FOR CO2 ABSORPTION

Absorption is the most widely used carbon dioxide (CO2) removal technology. The CO2 absorption performance of monoethanolamine (MEA), the most commonly used CO2 absorbent, can be improved by suspending nanoparticles. This work examined the performance of graphene nanoplatelets (GNPs) as additives to enhance CO2 absorption in MEA. The GNPs were characterized by HRTEM, FTIR, and XRD. The study examined the influence of GNP concentrations on CO2 absorption at room temperature. The images from HRTEM confirmed that the implemented graphene consists of several layers of graphene sheets. Increasing the loading of particles increased the solubility of CO2 until the optimum concentration was reached. From this work, it is evident that incorporating GNPs into MEA enhances the CO2 absorption performance of MEA. Thus, the addition of nanoparticles to the absorbent can enhance its CO2 absorptivity.

Influence of graphene nanoplatelet on carboxymethyl cellulose for enhanced electrochemical performance

Renewable and bio-based polymers are favored over conventional synthetic polymers because of their low-cost, abundance and sustainability, but due to their average electrochemical performance, sometimes their application is limited as battery material. This study investigates the electrochemical properties of nanocomposites composed of carboxymethyl cellulose (CMC) and graphene nanoplatelets (GNP) at varying GNP ratios. Four samples with GNP weight ratios ranging from 0 to 0.33 wt.% were subjected to analysis using electrochemical impedance spectroscopy (EIS), scanning electron microscopy (SEM), and Fourier transform infrared (FTIR) spectroscopy. The sample containing 0.33% GNP exhibited the most favorable electrochemical behavior, demonstrating an ionic conductivity of approximately 2.54 × 10−5 S/cm at 25 °C. Cyclic Voltammogram and Nyquist plots indicated an electrochemical process governed by diffusion processes, particularly evident with 0.33% GNP. This sample displayed the highest specific capacitance at 4.290 F/g, representing an 83.07% improvement over the Pure CMC sample, along with a favorable electrochemical window at 375 mV. Bode plot analysis underscored the influence of diffusion and charge transfer on resistance and conductivity, highlighting enhanced ion mobility in this sample. SEM micrographs revealed improved GNP dispersion in the CMC matrix at higher GNP concentrations, enhancing contact. FTIR analysis confirmed effective CMC–GNP interaction, characterized by a specific peak at 1589 cm−1. These findings provide valuable insights into the electrochemical potential of CMC–GNP composites, offering prospects for their application in diverse electrochemical devices.

Enhancing the electrochemical properties of biopolymer composites using starch‐graphene nanoplatelets

AbstractThe study presents the ideal distribution of graphene nanoplatelets (GNP) within the thermoplastic starch (TPS) matrix significantly elevated the thermal and electrical conductivities, as well as the electrochemical efficiency of the biocomposites. Additionally, the incorporation of GNP resulted in an increased thermal stability for the TPS, as indicated by the elevated temperatures required for maximum degradation. The biocomposites exhibited a self‐aligned layered structure, creating conductive pathways and enhancing electron conduction. An electrical conductivity increased as the concentration of GNP increased, with the highest conductivity observed on the top and bottom surface with the value of 4.23 × 10−7 S/m and 3.92 × 10−6 S/m when 12 wt% of GNP was added. The presence of hydroxyl groups in TPS facilitated the formation of hydrogen bonds with GNP, preventing GNP from stacking and forming a more uniform conductive network within the film. The addition of 15 wt% GNP also improved the capacitive performance of the TPS matrix, as evidenced by higher current responses and larger quasi‐rectangular areas in the cyclic voltammetry curves compared to neat TPS. The Nyquist plots which are illustrated impedance data showed that the TPS film with 12 wt% GNP exhibits the smallest semicircle, indicating the highest conductivity which is suggested that GNP improves charge transfer compared to pure TPS.Highlights Optimal dispersion of GNP enhanced the biocomposite's properties. The electrical conductivity increases with the GNP content until 12 wt%. TPS/GNP self‐aligned layered improved conduction and capacitive behavior. GNP improved thermal stability by restricting polymer chain movement. Electrochemical impedance shows improved properties of TPS/GNP.

Vat photopolymerization of polymer composites with printing-direction-independent properties

The implementation of additive manufacturing techniques for thermal management applications necessitates the development of printable materials with enhanced properties. This study focuses on enhancing the thermal and mechanical properties of 3D-printed polymer composites (UV-based vat photopolymerization; VPP), starting by loading graphene nanoplatelets (GNP) as fillers into a monomer solution. GNP stabilization in the solution is achieved via the addition of sepiolite, a fiber-like clay, that traps them in dispersion. However, the inherent GNP-UV blocking limits its concentration in the VPP-printed composite, and its 2D nature yields parts with undesired anisotropic properties. We overcome this GNP concentration limit by using the excluded volume approach, namely, adding micron-sized diamonds to increase the GNP effective concentration. This approach also transforms the anisotropic VPP-printed composite into an isotropic structure, ensuring consistent thermal and mechanical enhancement regardless of the printing direction. Thermal conductivity (TC) and fracture toughness (FT) are enhanced by 180 % and 100 %, respectively (vs. the neat polymer). However, the electrical conductivity (EC) is also enhanced, which is undesirable in thermal management systems (risk of short-circuiting). Therefore, hexagonal boron nitride is added to reduce the EC, producing composites with enhanced TC and 140 % FT enhancement. Our approach holds promise for various applications, especially in advanced heat management solutions, where enhanced TC, light weight, and low EC are imperative.