Addition Of Graphene Nanoplatelets Research Articles

Role of aloe vera based nanofluids for cool thermal energy storage system: A comparative study

The present experimental investigation incorporates the preparation of aloe vera gel-based phase change nanofluid (NFPCM) for a cool thermal energy storage (CTES) system. Two sets of NFPCMs were produced by adding graphene nanoplatelets (GNP) in deionized water and aloe vera gel (0.20 wt%, 0.40 wt%, and 0.60 wt%). The zeta potential analysis shows that the NFPCM with aloe vera gel is more stable even after 60 days from the preparation (−44 mV). The thermal conductivity of NFPCMs was analyzed through the transient hot wire method and the enhancement of 42 %, and 37.5 % were measured in the ice phase for NFPCMs with aloe vera gel and DI water (0.60 wt%) respectively at the heat transfer fluid temperature of −15 °C. The NFPCMs with aloe vera gel show that the addition of GNP prepended the peak melting temperature from −16 °C to −10.5 °C, which is due to the quick formation of nuclei as compared to NFPCMs with DI water. Additionally, a slight reduction in the latent heat of only 7 % was observed. The charging characteristics of NFPCMs were studied in a single spherical capsule at −8 °C. The maximum reduction in total charging time of 25 % was recorded for the aloe vera gel-based NFPCM with a maximum concentration of GNP (0.60 wt%). The green synthesis of aloe vera gel-based NFPCM exhibited noteworthy enhancements in thermophysical properties. Additionally, it was observed that the long-term stability of the NFPCM was achieved by excluding surfactants during the preparation process. The incorporation of graphene nanoplatelets (GNP) into aloe vera gel as the foundational phase change material (PCM) facilitates the partial charging of the CTES system with a reduced energy input.

Computational fluid dynamics simulations of the heat transfer properties of graphene-based nanolubricants and application to hydrodynamic lubrication

In this paper, we consider experimental data available for graphene-based nanolubricants to evaluate their convective heat transfer performance by means of computational fluid dynamics (CFD) simulations. Single-phase models with temperature-dependent properties are employed for this purpose. The base fluid is a polyalkylene glycol, and we show the effect of the addition of carbon nanohorns and graphene nanoplatelets (GNPs), in different volume fractions, on the convective heat transfer coefficient between two parallel plates. Then, an application to hydrodynamic lubrication is discussed. The extreme in-plane thermal conductivity of graphene allows a smaller temperature rise of the GNP-based nanolubricant, i.e., a more effective heat removal. To the best of our knowledge, this work represents the first application of single-phase nanofluid models to hydrodynamic lubrication.

The influence of GNP on the mechanical and thermomechanical properties of epoxy adhesive: Pearson correlation matrix and heatmap application in data interpretation

AbstractThis article explores the impact of Graphene Nanoplatelet (GNP) reinforcement on the mechanical and thermomechanical properties of epoxy adhesive. The impact of GNPs on the structural adhesive largely depends on factors like dispersion stability and GNP concentration. Given the complexity of these interactions, it is imperative to obtain indicators for the degree of each interaction. In this study, Pearson correlation matrix and heatmaps analysis were used to analyze the relationship between various variables and the strength of the connection. The addition of GNP at various concentrations to the epoxy adhesive led to a reduction in storage modulus, loss modulus, and glass transition temperature, attributed to the agglomeration of GNP. In bulk specimens, the incorporation of GNP, regardless of its content, has decreased tensile stress up to 70.7% while increasing its fracture elongation up to 396.3%. Within joining specimens with GNP, specimens with 1.5 wt% GNP content showed the highest cohesive fracture mode and largest shear strength. Pearson correlation matrix and heatmaps have demonstrated very good accuracy in reflecting the experimental data. They offer a comprehensive assessment of the relationship between various variables while indicating the degree of influence each variable has on the properties of the adhesive and joining specimens.Highlights GNP effects in adhesive can be accurately analyzed with Pearson correlation matrix & heatmaps. Connections strength for various variables can be shown by Pearson correlation matrix & heatmaps. Pearson correlation matrix & heatmaps assess variable relationships comprehensively.

Effect of water immersion on shear strength of epoxy adhesive filled with graphene nanoplatelets

Abstract Adhesive bonds are frequently used in industries such as aerospace, automotive, and civil engineering due to their ability to reduce damage to the adherend and their lightweight. However, their application is restricted by their inadequate durability and reliability in hostile environments. Graphene nanoplatelets (GNPs) are employed to enhance epoxy adhesives in this article. The thick adherend shear test is utilized to examine how the shear properties change with different water ageing times. Before exposure to water ageing conditions, GNP-reinforced adhesives exhibit a 3.51% increase compared with neat epoxy at a GNP content of 0.25 wt%. However, after 56 days of water ageing, the increase in shear strength is found to be 13.79%. This suggests that the well-dispersed GNP can reduce the degradation rate in shear properties by half, from 16.71 to 8.44%, at a GNP content of 0.25 wt%. Additionally, as water ageing time increases, the positive influence of GNP on shear properties becomes more evident. The addition of GNP delays the degradation of shear properties caused by water ageing conditions. The effect of GNP does not improve with higher GNP content. When the GNP contents increase to 1 wt%, the shear strength of the GNP-reinforced adhesive decreases compared to neat epoxy.

Fatigue response of multiscale extrusion-based additively manufactured acrylonitrile butadiene styrene-graphene nanoplatelets composites

This study investigates the effect of varying concentrations of graphene nanoplatelets (GNPs) on the mechanical and fatigue characteristics of acrylonitrile butadiene styrene (ABS)/GNPs nanocomposites, both in filament form and as 3D-printed parts with different raster orientations. Quasi-static and cyclic loading tests were performed on specimens containing 0.1 wt%, 0.5 wt%, 1.0 wt%, and 2.0 wt% GNPs. The results indicated that the addition of 0.1 wt% GNPs to the ABS polymer matrix increased the ultimate tensile strength (UTS) of the filament by 18 %. Addition of 1.0 wt% and 2.0 wt% GNPs to the matrix improved the Young's modulus of the filament by up to about 35 % but did not enhance the UTS. The filament containing 0.5 wt% GNPs demonstrated the highest fatigue life, even higher than that of the standard samples fabricated through injection molding technique. This was due to its high static strength, Young's modulus, and ductility. However, when the ABS/GNPs nanocomposites were 3D-printed, the addition of GNPs had no major impact on their fatigue life, especially in the higher load levels. Inadequate adhesion and reduced interlayer bonding strength resulted in a detrimental impact on fatigue life of 3D-printed objects. The extrudate-swell phenomenon seems to significantly affect this reduction in fatigue life. To address this, larger nozzle diameter (0.6 mm) was used in fabricating 3D-printed samples. Results indicated that samples with less distortion and smaller extrudate-swell had higher fatigue life. It highlights the importance of considering GNP concentration and printing parameters for optimal fatigue properties in ABS/GNPs composites.

Enhanced anti-welding and arc erosion performance of Ag-8 wt%SnO2 contact material with different addition of graphene nanoplatelets

To improve the welding resistance of Ag-8 wt%SnO2 contact material at large current, the graphene nanoplatelets (GNPs) was selected as the additive, and Ag-8 wt%SnO2 contact materials with different GNPs addition were prepared by powder metallurgy route. The electrical contact tests were performed under 36 V/16 A and 36 V/25 A, the welding, material transfer behavior and their mechanism were investigated combined with the analysis of arc duration, arc power and eroded morphology. The results show that 0.2 wt% GNPs addition decreases the welding frequency and welding force significantly, this can be attributed to the arc extinction effect and the weaken effect of the welding area. However, the excessive GNPs addition in turn aggravates the welding, the reason is that excessive GNPs addition weakens the bond between eroded layers, resulting in the decrease of arc stability and the generation of the small protrusion which cause the concentration of the contact stress and the electric field, which further results in the serious welding. Furthermore, 0.2 wt% GNPs addition decreases the mass loss rate, increasing the combination performance of Ag-8 wt%SnO2 contact material.

Enhanced magneto-dielectric characteristics of Ni–Cd ferrites/GNPs composites synthesized via sol-gel auto-combustion method

Graphene nanoplatelets (GNPs) and spinel ferrites (SFs) composites enhance their properties and enable multifunctional applications, ranging from electronics to environmental and biomedical fields. This study investigates the Ni0.4Cd0.6Fe2O4/x-GNPs (x = 0 %, 2.5 %, and 5 %) [NCF/0%GNPs, NCF/2.5%GNPs, and NCF/5%GNPs] composites prepared via sol-gel auto combustion (SGAC) synthesis and their enhanced magneto-dielectric characteristics. XRD analysis confirmed the formation of a single-phase spinel matrix of NCF/GNPs composites and observed that the crystallite size (D) was enhanced from 22.8 nm to 33.6 nm with the increasing concentration of GNPs. Moreover, the bandgap energy (Eg) was reduced with the incorporation of GNPs in the NCF sample. The dielectric constant and tangent loss were enhanced with the addition of GNPs in the NCF spinel lattice. The saturation magnetization and microwave operating frequency were reduced from 97.42 emu/g to 55.13 emu/g and 21.49 GHz–11.97 GHz, respectively, while the coercivity was observed to increase from 92.66 Oe to 263 Oe with the incorporation of GNPs in the NCF lattice. The study highlights the potential of NCF/GNPs composites for applications in electronics, energy storage, sensors, and biomedical devices.

The Incorporation of Graphene Nanoplatelets in Tung Oil-Urea Formaldehyde Microcapsules: A Paradigm Shift in Physicochemical Enhancement.

Tung oil (TO) microcapsules (MCs) with a poly(urea-formaldehyde) (PUF) shell were synthesized via one-step in situ polymerization, with the addition of graphene nanoplatelets (GNPs) (1-5 wt. %). The synergistic effects of emulsifiers between gelatin (gel) and Tween 80 were observed, with gel chosen to formulate the MCs due to its enhanced droplet stability. SEM images then displayed an increased shell roughness of the TO-GNP MCs in comparison to the pure TO MCs due to the GNP species on the shell. At the same time, high-resolution transmission electron microscopy (TEM) images also confirmed the presence of GNPs on the outer layer of the MCs, with the stacked graphene layers composed of 5-7 layers with an interlayer distance of ~0.37 nm. Cross-sectional TEM imaging of the MCs also confirmed the successful encapsulation of the GNPs in the core of the MCs. Micromanipulation measurements displayed that the 5% GNPs increased the toughness by 71% compared to the pure TO MCs, due to the reduction in the fractional free volume of the core material. When the MCs were dispersed in an epoxy coating and applied on a metallic substrate, excellent healing capacities of up to 93% were observed for the 5% GNP samples, and 87% for the pure TO MC coatings. The coatings also exhibited excellent corrosion resistance for all samples up to 7 days, with the GNP samples offering a more strenuous path for the corrosive agents.

Investigating the Effect of GNP Addition on Self-healing of ECC through Mechanical and Nondestructive Testing

Inclusion of nanomaterials is an effective method for enhancing the mechanical and durability characteristics of cement-based materials. Among various graphene-based nanomaterials, graphene nanoplatelets (GNPs) are cost-effective nanoparticles that possess graphene's key properties. Since limited information is available regarding their influence on the fresh, mechanical, non-destructive, and self-healing behavior of Engineered Cementitious Composites (ECC), this research focuses on GNP inclusion on these properties of ECC in a comprehensive way. In this research, the changes in material properties of ECC were monitored with several mechanical and nondestructive test methods. According to the results, GNP inclusion significantly enhanced flexural behavior and also promoted self-healing of ECC, with preloaded specimens exhibiting substantial or complete crack closure and similar performance to virgin specimens. Non-destructive tests and microstructural analyses also confirmed the promoting effects of GNP. A noticeable increase was observed in compressive strength when GNP was included. In conclusion, this study provides compelling evidence about the positive impact of GNP inclusion on improving the properties of ECC. The findings demonstrate the potential of GNPs to enhance the performance of cementitious materials and offer valuable insights for future research and practical applications.

Infusion Simulation of Graphene-Enhanced Resin in LCM for Thermal and Chemo-Rheological Analysis.

The present numerical study proposes a framework to determine the heat flow parameters-specific heat and thermal conductivity-of resin-graphene nanoplatelets (GNPs) (modified) as well as non-modified resin (with no GNPs). This is performed by evaluating the exothermic reaction which occurs during both the filling and post-filling stages of Liquid Composite Moulding (LCM). The proposed model uses ANSYS Fluent to solve the Stokes-Brinkman (momentum and mass), energy, and chemical species conservation equations to a describe nano-filled resin infusion, chemo-rheological changes, and heat release/transfer simultaneously on a Representative Volume Element (RVE). The transient Volume-of-Fluid (VOF) method is employed to track free-surface propagation (resin-air interface) throughout the computational domain. A User-Defined Function (UDF) is developed together with a User-Defined Scaler (UDS) to incorporate the heat generation (polymerisation), which is added as an extra source term into the energy equation. A separate UDF is used to capture intra-tow (microscopic) flow by adding a source term into the momentum equation. The numerical findings indicate that the incorporation of GNPs can accelerate the curing of the resin system due to the high thermal conductivity of the nanofiller. Furthermore, the model proves its capability in predicting the specific heat and thermal conductivity of the modified and non-modified resin systems utilising the computed heat of reaction data. The analysis shows an increase of ∼15% in the specific heat and thermal conductivity due to different mould temperatures applied (110-170 °C). This, furthermore, stresses the fact that the addition of GNPs (0.2 wt.%) improves the resin-specific heat by 3.68% and thermal conductivity by 58% in comparison to the non-modified thermoset resin. The numerical findings show a satisfactory agreement with and in the range of experimental data available in the literature.

Dielectric and magnetic response of Cu-Co-Sm ferrite impregnated with graphene nanoplatelets for high-frequency device applications

This work studied a composite of graphene nanoplatelets (GNPs) impregnated copper-cobalt-samarium ferrites Cu0.5Co0.5Fe1.97Sm0.03O4/GNPs synthesized via sol-gel auto-combustion route. The structural, electrical, dielectric, and optical properties of the as-prepared composites were investigated by X-ray diffraction (XRD), transmission electron microscopy (TEM), EDX, I-V characteristics, impedance measurement, raman spectroscopy, scanning electron microscopy (SEM), vibrating sample magnetometry (VSM) analysis, and UV–visible spectroscopy. XRD confirmed that the spinel ferrites had a crystalline single-phase FCC structure with the lattice constant of around 8.33 Å, and the crystallite size range from 54.10 nm to 51.85 nm. SEM analysis confirmed the homogenous dispersion of spinel ferrites in graphene sheets, and EDX confirmed the presence of all elements in ferrite composites with GNPs. Furthermore, the spinel matrix was confirmed by the Raman and UV-visible analysis. A minimum particle size of 21.73 nm was determined using TEM, and the minimum value of activation energy (0.01 eV) was obtained from IV characteristics for ferrite composite with 2.5% GNPs. Further, our ferrite composites with GNPs demonstrated improved electroconductive properties, with conductivity ranging from 5.88×10−8S/cm to 1.04×10−6S/cm at 673 K. The real & imaginary part of permittivity, dielectric constant (ε’), and impedance (Z) were also improved with the addition of GNPs. At low frequencies, a permeability loss value of 0.81 was obtained for the ferrite composite with 5% GNPs. VSM analysis confirmed that the saturation magnetization decreased in ferrite composites with graphene nanoplatelets. The minimum value of skin depth of 1.03 mm was observed at 1.25 % GNPs. Our ferrite composites with GNPs exhibited minimal eddy current at high frequencies, making them promising candidates for high-frequency device applications.

An unexpected hardening behaviour of carbon-fiber epoxy composites under flexural fatigue loading and its intensification by graphene nano-fillers

The fatigue performance of carbon fiber reinforced polymer (CFRP) composites under cyclic loading remains a significant concern in various engineering applications due to the complex damage mechanisms and uncertain failure modes associated with these materials. Despite their exceptional strength-to-weight ratio, CFRP composites are prone to progressive damage accumulation, leading to premature failure and reduced structural integrity. The present study investigates the flexural fatigue response of pristine CFRPs and CFRPs with added graphene nanoplatelets (GNPs), accompanied by in-situ microscopy for progressive damage analysis. Eight layers of carbon fibers fabric, both pristine and GNP coated were utilized to fabricate the composites using vacuum-assisted resin transfer molding (VARTM) technique. GNP-added composites exhibited significantly improved monotonic flexural strength, strain and fatigue life compared to pristine composites. The dissipated strain energy density (DSED) was also evaluated as a function of cycles and correlated with the damage that happened in the composite using in-situ optical imaging. While cycling at or below three-quarters of the maximum tensile stress, it was observed that the DSED decreased with the number of cycles in both composites. However, at higher loads, the DSED was found to increase progressively, ultimately shooting up during catastrophic failure. These composites that showed a decrease in DSED with cycles, did not fail even at one million cycles and had a higher residual strength than the original when they were forced to break under monotonic loading and the percentage increment was even higher when GNPs were used. Additionally, post-failure fracture surface examination using scanning electron microscopy (SEM) was conducted to understand the influence of GNP addition on damage evolution of CFRPs.

The Effects of Indium Additions on Tribological Behavior of Spark Plasma Sintering-Produced Graphene-Doped Alumina Matrix Composites for Self-Lubricating Applications

Alumina (Al2O3) ceramics are interesting for low-weight and mid-high temperature applications. The addition of indium (In) and graphene nanoplatelets (GNPs) can be used to reduce the density and modify the functional properties and mechanical performance of the ceramic matrix. GNP and In-reinforced Al2O3 matrix composites were prepared by the spark plasma sintering (SPS) technique. Monolithic Al2O3 and Al2O3 matrix composites with either 5 or 10 wt.% of In and 2 wt.% of GNPs (Al2O3-5In-2GNPs and Al2O3-10In-2GNPs) were compacted into disc-shaped samples. The microstructure was studied and characterized with light-optical microscopy (LOM) and scanning electron microscopy (SEM). Hardness was determined using the Vickers technique and tribological properties were studied by the ball-on-disk method. The coefficient of friction (COF) and specific wear rates were evaluated from tribological tests. Worn surfaces were studied by SEM and confocal microscopy. Interdiffusion transition regions were formed among individual microstructural constituents (Al2O3, In, GNPs) under high sintering temperatures, which were responsible for the balanced hardness and low porosity of the produced composites. The addition of In and graphene nanoplatelets resulted in smaller COF and wear rates indicating good improvement in the tribological behavior. The prepared Al2O3-5In-2GNP and Al2O3-10In-2GNP composites represent promising nanocomposites for self-lubricating applications.

A quasi-3D hyperbolic formulation for the buckling study of metal foam microplates layered with graphene nanoplatelets-embedded nanocomposite patches with temperature fluctuations

The work analyzes the buckling behavior of size-dependent microplates with a metal foam core, covered by graphene nanoplatelets (GNPs)-embedded nanocomposite patches. Microplates rest on a bi-parameter elastic substrate, and they are immersed in a thermal environment to observe the effect of temperature fluctuations on their elastic buckling performance. All material properties for each layer of the microstructure are thickness-dependent. A novel quasi-3D shear and normal (Q-3D S-N) hyperbolic theory is here proposed to describe the kinematic relations, accounting for the transverse normal strain. At the same time, a modified couple stress theory (MCST) is employed to account for the size dependence of the mechanical behavior due to the presence of a material length-scale parameter. Using the energy method and virtual work principle, the differential equilibrium equations are derived and solved analytically, where solutions are verified against the existing literature. The study focuses on the impact of different parameters on the normalized critical buckling load (NCBL). Based on the results from the systematic investigation, it is found that the addition of GNPs to the microplate enhances its stiffness, leading to increased values of NCBL, which in turn reduce for an increased imperfection ratio.

Synthesis, characterization, thermal and mechanical behavior of polypropylene hybrid composites embedded with CaCO<sub>3</sub> and graphene nano-platelets (GNPs) for structural applications

<abstract> <p>In this study, ultra-fine graphene nanoplatelets (GNPs) were employed as nanofillers to reinforce a polypropylene (PP) matrix. This was done in conjunction with a polypropylene grafted maleic anhydride (PP-MAH) compatibilizer and calcium carbonate (CaCO<sub>3</sub>), with the aim of improving the mechanical and thermal properties of the resulting hybrid composites. Formulations for the hybrid composites were fabricated by compounding the PP matrix with varying weight percentages of GNPs (x = 0.5, 1.0, 1.5, 2.0), 2 wt.% CaCO<sub>3</sub>, and 5 wt.% PP-MAH using a twin-screw extruder followed by injection molding. This research thoroughly investigates the mechanical and thermal characteristics. X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and Fourier-transform infrared spectroscopy (FTIR) results confirm the successful development of hybrid composites. The thermal stability, crystallization temperature, melting temperature, tensile strength, flexural strength, and impact resistance were evaluated using differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), universal testing machine, and low-velocity impact tester, respectively. The results indicated a significant improvement in the tensile strength of the PP matrix with the addition of GNPs, with the highest enhancement observed at 1.5 wt.% GNP loading, where the tensile strength reached a maximum of 40.54 MPa. This improvement was attributed to the proper interconnection, bonding, and compounding of PP with GNPs, thus leading to an increase in the load transfer efficiency.</p> </abstract>

Experimental and simulation analysis of the effect of GNPs on the mechanical and interfacial properties of CF/PEEK-Ti fiber metal laminates

In this study, graphene nanoplatelets (GNPs) were used to improve the interfacial and mechanical properties of carbon fibre-reinforced polyetheretherketone-based titanium alloy laminates (CF/PEEK-Ti) and molecular dynamics (MD) simulations were used to investigate the mechanism by which GNPs improve CF/PEEK-Ti, collectively known as fibre reinforced metal laminates (FMLs). In addition, surface anodising of titanium (Ti) sheets was used further to enhance the interfacial bonding properties of the FMLs. The experimental results showed that the flexural and shear strengths of the anodised FMLs were increased by 77.7% and 29.5%, respectively, compared with those of the Ti plates without surface anodisation. Based on this, different levels (0–1.5 wt.%) of GNPs were added to the FMLs matrix, and test results showed that FMLs containing 0.5 wt.% GNPs had the best flexural and shear strengths, 108.9% and 130.8% higher than untreated FMLs without GNPs. In addition, an in-depth microscopic analysis was carried out to understand the enhancement mechanism of GNPs on FMLs. Finally, MD simulations were used to analyze the role and mechanism of GNPs in this system. The results show that the addition of GNPs can increase the interfacial energy of FMLs. In other words, the interfacial mechanical properties of FMLs are improved. The effect of the dispersion of GNPs on the interfacial properties of FMLs was also investigated. The polyetheretherketone (PEEK) matrix could be significantly improved by well-dispersed GNPs. These findings provide insight into designing high-performing composites for various engineering applications.

Conductive and auxetic composite membranes based on graphene nanoplatelets and polybutylene succinate produced via electrospinning

AbstractThis work presents a method to produce conductive and auxetic composite membranes from a biobased and biodegradable matrix: polybutylene succinate (PBS). The conductivity was improved by the addition of graphene nanoplatelets (GNP) and the samples were produced via solution electrospinning. The membrane properties were shown to increase with increasing GNP concentration and the rotational speed of the collector. In particular, a membrane having 0.2% w/v GNP and fabricated at the highest collector speed (9.96 m/s) showed the highest electrical conductivity (1.56 × 10−4 S/m) while having a negative Poisson's ratio (NPR) of −1.5 in tension. To complete the analysis, mechanical characterizations showed that the presence of GNP led to a substantial increase in Young's modulus (234%) and tensile strength (190%) compared to the neat PBS membrane produced under the same conditions. Differential scanning calorimetry (DSC) revealed a slight crystallinity increase since GNP are acting as heterogeneous nucleating agents, while thermogravimetric analysis (TGA) showed an improved thermal stability for the GNP/PBS membranes. This unique combination of auxetic and conductive properties can be useful for a wide range of innovative applications such as electronic devices, smart textiles, biomaterials, and biomedical devices.Highlights Electrospinning was successful to produce polybutylene succinate (PBS) nanofibers. A careful control of the processing conditions led to auxetic fiber mats. Electrically conductive mats were produced by adding graphene nanoplatelets (GNP) to PBS. The PBS mechanical properties were highly improved (200%) with low GNP content (0.2%).

Evaluating Gelatin-Based Films with Graphene Nanoparticles for Wound Healing Applications

In this study, gelatin-based films containing graphene nanoparticles were obtained. Nanoparticles were taken from four chosen commercial graphene nanoplatelets with different surface areas, such as 150 m2/g, 300 m2/g, 500 m2/g, and 750 m2/g, obtained in different conditions. Their morphology was observed using SEM with STEM mode; porosity, Raman spectra and elemental analysis were checked; and biological properties, such as hemolysis and cytotoxicity, were evaluated. Then, the selected biocompatible nanoparticles were used as the gelatin film modification with 10% concentration. As a result of solvent evaporation, homogeneous thin films were obtained. The surface’s properties, mechanical strength, antioxidant activity, and water vapor permeation rate were examined to select the appropriate film for biomedical applications. We found that the addition of graphene nanoplatelets had a significant effect on the properties of materials, improving surface roughness, surface free energy, antioxidant activity, tensile strength, and Young’s modulus. For the most favorable candidate for wound dressing applications, we chose a gelatin film containing nanoparticles with a surface area of 500 m2/g.

Doping of Co3O4–ZrO2 in graphene nanoplatelets for enhanced electrochemical catalytic degradation of phenol

This study presents the synthesis of CO3O4–ZrO2 (CZ) doped Graphene nanoplatelets (GNPs) composite (GNPs-CZ) via simple co-precipitation route and was drop casted on carbon fiber paper (CFP) to fabricate the modified electrochemical sensor (GNPs-CZ/CFP) electrode for sensitive determination of phenol (Ph) in 0.1 M phosphate buffer solution (PBS). The physico-chemical characterization was done by Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD), thermo-gravimetric analysis (TGA), scanning electron microscopy (SEM), and transmission electron microscopy (TEM). GNPs-CZ composite exhibits enhanced electrochemical behavior towards Ph as shown by voltammetric techniques. The enhanced electro-oxidation of Ph was attributed to the joint efficiency of GNPs and CZ. Co3O4 being very surface sensitive to carbonate species; the introduction of ZrO2 to it stabilizes its active sites and enhances the decomposition of carbonate. Electrode fouling is the prime hurdle in electrochemical detection of Ph as the bare electrode gets poisoned due to dimerization of phenol and the oxidation current decreases. This challenge was removed by coating the bare electrode with GNPs-CZ composite. The addition of GNPs effectively improves the surface area, and enhances the electrons transfer rate showing better electrocatalytic response. A higher sensitivity (748 μA mM˗1), appreciable detection limit (74 μM), and wide linear range (20˗400 μM) with good stability are achieved. Thus, the GNPs-CZ/CFP electrode has the potential to be used as Ph electrochemical sensor for pollution control scenario.

Preparation of antistatic and biodegradable packaging of PLA/PHBV blend‐based glassy carbon and graphene nanoplatelets composites

AbstractGlassy carbon (GC) and graphene nanoplatelets (GNP) were used as fillers for the preparation of antistatic and biodegradable composites based on poly (lactic acid)/poly(3‐hydroxybutyrate‐co‐3‐hydroxyvalerate) (PLA/PHBV) blend. In this work, PLA/PHBV (80/20) blends with the addition of different GC contents (0.1, 0.3, and 0.5 wt%) were prepared by melt mixing using a twin‐screw extruder, and specimens were injection molded. Furthermore, hybrid composites were prepared with the addition of 5 wt% of GNP and different GC contents (0.1, 0.3, and 0.5 wt%) using the same processing. The effect of the addition of GC and GNP on the mechanical, electrical, and electromagnetic properties and its effect on the biodegradability of the PLA/PHVB blend was evaluated. The simultaneous addition of GC (0.3 and 0.5 wt%) and GNP (5 wt%) significantly increases the elastic modulus and decreases the electrical resistivity, becoming suitable for electrostatic discharge protection packaging applications. The hybrid composite GC0.5/GNP5 reached a maximum value of total attenuation (4.5 dB), which corresponds to 60% EMI shielding. The degree of crystallinity affects biodegradability more than the type or presence of carbon material. After 110 days of anaerobic biodegradation, the hybrid composite exhibited 10% biodegradability due to the high degree of crystallinity that hinders the biodegradability process. The hybrid composites with the addition of GC and GNP are very promising for use in antistatic packaging.