Addition Of Nanoplatelets Research Articles

Thermal performance investigation of microencapsulated phase change material enhanced with graphene nanoplatelets in double-glazing applications

Effective heat energy storage is crucial for thermal energy management. The utilization of latent heat storage methods is widely prevalent across various engineering applications for enhancing energy efficiency. In this study, the energy storage performances of Phase Change Materials (PCMs) achieved by incorporating graphene nanoplatelets into a microencapsulated PCM were experimentally analyzed for double-glazing applications. Changes in thermal energy storage and heat transfer performance by incorporating graphene nanoplatelets into the PCM at two different mass ratios (1 % and 0.1 %) were investigated. The results obtained from light intensity and temperature measurements, as well as thermal camera imaging, were evaluated together. The results support the contribution of graphene nanoplatelets addition to microencapsulated PCMs in enhancing thermal performance during both heating and cooling periods. Among the investigated cases, the highest mass ratio of 1 % graphene nanoplatelets addition led to a major 10 °C increase in peak temperature compared to the reference condition. In contrast, this increase in peak temperature was accompanied by a mere 14 % decrease in average light levels. This research underlines the potential of graphene-enhanced microencapsulated PCMs in optimizing thermal management systems for double-glazing applications, offering a promising pathway towards enhancing energy efficiency and thermal comfort in building environments.

Influences of graphene nanoplatelet addition and pin lengths on the microstructure and mechanical properties of 7075 aluminum alloy under friction stir spot welding

This study investigated the impact of graphene nanoplatelets (GNPs) and pin lengths on the mechanical properties and microstructure of AA7075 Al alloy in friction stir spot welded (FSSW) joints. FSSW was conducted using varying volumes of GNPs (5, 10, 20, and 30 mm3) and different pin lengths (3.5 and 4 mm) with 1250 rpm of rotational speed and 10 s of dwell time. The results of this study indicated that the addition of GNPs led to significant grain refinement in the stir zone (SZ). An increase in GNPs volume from 5 to 30 mm3 resulted in substantial grain refinement during FSSW. This outcome was obtained from the pinning effect generated by nano-sized GNPs. This effect successfully hindered grain growth, followed by recrystallization during FSSW. Furthermore, the grain size grows as the pin length increases. The results of tensile lap shear tests revealed that 3.5 mm pin length and 10 mm3 volume of GNPs are the best welding conditions for the fabrication of the best-quality welds. The increase in the volume of GNPs of more than 10 mm3 induced a negative impact on the tensile shear strength due to the agglomeration of the GNPs. The tensile shear strength of the joints with 10 mm3 GNPs and pin lengths of 3.5 and 4 mm exhibited remarkable increases of 52.6% and 41.2%, respectively, compared with that of those without GNPs. Moreover, the microhardness of the SZ of the joints improved by increasing the addition of GNPs volume.

Hexagonal Boron Nitride Nanoplatelets Filled Polyphenylene Sulphide Nanocomposites: Influence on Thermal and Dielectric Properties

The Hexagonal Boron Nitride (hBN) nanoplatelets are synthesized using a wet chemical method. X-Ray Diffraction (XRD) shows the hBN nanoplatelets exfoliates along the (002) plane. Transmission Electron Microscope (TEM) observation shows the exfoliated hBN nanoplatelets. The hBN nanoplatelets and polyphenylene suulfiude (PPS) physical mixture are solvent processed using ethyl alcohol. It involves two step processing with the first step of ultrasonic treatment of hBN nanoplatelet in ethyl alcohol followed by mixing it with PPS powder and further sonication. This mixed powder of PPS and hBN nanoplatelets are hot pressed using a compression moulding machine. With more addition of hBN nanoplatelets in PPS matrix shows the enhancement in dielectric constant. In addition, the dispersion of hBN nanoplatelets in the PPS matrix increases the crystallinity and thermal stability.

A Prediction of Graphene Nanoplatelets Addition Effects on Diesel Engine Emissions

There are numerous methods for reducing diesel exhaust emissions. Engine modifications, combustion optimization, and exhaust gas treatment are all popular methods. Another proven method uses fuel additives, such as zinc oxide, copper oxide, and magnesium oxide. Those additives are proven to reduce measured emissions such as carbon monoxide and nitrogen oxide successfully; however, there are still concerns about the toxicity of the emissions, which could harm human health. As a result, carbon nanoparticles have been introduced as a fuel additive due to their low risk to human health. Because of advancements in graphene research, a few researchers began investigating the implications of using graphene nanoplatelets as a fuel additive. The study’s findings appeared to be encouraging. However, no additional research has been identified to forecast the impact on engine emissions other than analyzing the effects of graphene additives on engine emissions. The goal of this study is to forecast the effects of graphene nanoplatelets on diesel engine emissions. The emission parameters of the trial were carbon monoxide, carbon dioxide and nitrogen oxide. The factors considered in the experiment are speed, load, and blend concentration. Response surface methodology and contour plots were generated using Minitab software. The results show that the prediction model’s accuracy is within 10% of the experimental data.

Effect of graphene nanoplatelets on fatigue performance of Glass Fiber Reinforced Composite materials based on recycled polyethylene terephthalate

Utilization of recycled polyethylene terephthalate (PET) based resins for manufacturing composites is an environment friendly and cost effective solution. This study attempts to explore the influence of graphene nanoplatelets (GPnP) addition on the fatigue performance of glass fiber reinforced composites based on recycled PET in terms of S–N Data, area of hysteresis loops during fatigue loading, fatigue life distributions, self generated temperature during fatigue loading and stiffness degradation. Incorporation of GPnP in rPET-UPR based composites brings their fatigue performance at par with virgin polyester resin based composites. Statistical analysis of fatigue life data using two parameter Weibull distribution established that GPnP addition has only marginal effect in increasing dispersion in fatigue lives.

The effect of graphene nanoplatelet addition on the mechanical, durability and self-healing properties of engineered cementitious composites

Nanomaterial usage is an effective method to enhance the mechanical and durability properties of cementitious materials. Graphene Nanoplatelets (GNPs) are cost-efficient graphene-based nanomaterials that can exhibit graphene-like features. Although GNPs have been found to improve mechanical and durability properties, their effect on the self-healing behavior of cementitious materials, particularly Engineered Cementitious Composites (ECC), has not been examined in the literature studies. Therefore, this study aims to investigate the effects of GNP addition on mechanical, durability and self-healing behavior of ECC. During the study, the mechanical, durability, and self-healing characteristics of ECC with and without GNP were observed by using various mechanical and non-destructive test methods. Compression test, four-point bending test, resonance frequency test, ultrasonic pulse velocity test, sorptivity test, electrical impedance test and microscopic inspection were conducted. According to the test results, 0.05% GNP addition increased the compressive strength of ECC specimens. With the effect of GNP, first cracking strength, ultimate flexural strength and deformation values increased both for virgin and preloaded ECC specimens. The preloaded specimens with GNP performed similarly to virgin specimens under bending. The cracks of preloaded GNP specimens were either closed completely or extensively compared to control specimens. The crack numbers of GNP specimens after failure were also greater than that of control specimens. Accordingly, the flexural and self-healing behavior of the specimens improved with GNP addition. The effect of improvement by GNP addition was also evident in nondestructive tests. A considerable increment occurred in electrical resistance with GNP addition.

Effects of exfoliated graphite addition in ultra-trace concentration on industrial-scale lead-acid battery performance

The present investigation has the main objective to elucidate the hypothesis whether the addition of graphite nanoplatelets in ultra-trace concentrations (mg.kg-1) in negative plates are able to affect the electrochemical behavior of lead-acid batteries. The 60 Ah full scale batteries were produced in an industrial unit and assembled with three types of graphite nanoplatelets of different exfoliation intensities and in five different concentrations. Through electrical tests, it was possible to establish that certain concentrations of types of these additives are capable of increasing CCA performance, charge acceptance and PSOC cycling. The analysis of the structure (new, charged and discharged and post mortem) through SEM and evaluation of the macroporosity variation identified that the increase in electrochemical performance is associated with the structural change caused by the addition of these additives. Due to the small amounts of additives involved, the polarization is only slightly altered, signaling that the water loss is not appreciably affected. Discharge tests with constant current and interruptions reinforce the idea that the structure can be positively modified to increase electrochemical performance.

The Influence of Graphene Nanoplatelets Addition on the Electrical and Mechanical Properties of Pure Aluminum Used in High-Capacity Conductors

The main objective of this research is to assess a graphene/Al nanocomposite with a higher strength and conductivity for use in high-capacity conductors in power transmission lines. In this study, the graphene/Al nanocomposite and pure aluminum specimens were prepared using ball milling of aluminum and graphene powders, the mechanical-electromagnetic stirrer casting process, hot extrusion and finally, annealing. The microstructural, mechanical and electrical behavior of the Al 1350 nanocomposite cast reinforced with 0.5 wt% graphene and unreinforced aluminum were studied at 20 °C and 180 °C temperatures. The results revealed that, by adding graphene to pure aluminum, the tensile strength, toughness and electrical conductivity increased, but the elongation of the Al–0.5 wt% GNP composite decreased at both temperatures.

Design of Experiment to Predict the Effects of Graphene Nanoplatelets Addition to Diesel Engine Performance

To minimise diesel exhaust emissions, a few methods are commonly used. Engine modifications, combustion optimisation, and exhaust system treatment components are among them. Fuel additives, such as zinc oxide, titanium oxide, aluminium oxide, and cerium oxide, are amongst the most effective methods to increase performance and reduce emissions. Even while positive performance and emission reduction outcomes have been demonstrated, there are worries concerning health toxicity effects. Carbon nanoparticles have been accepted as a fuel additive since they pose little risk to human health. A few studies have been undertaken to investigate the consequences of employing graphene nanoplatelets as fuel additives, thanks to advancements in graphene research. The findings of the study seemed encouraging. However, despite detecting the additive effects of graphene on performance, no more study has been undertaken to forecast the effects on engine performance. The objective of this study was to predict the effects of graphene nanoplatelets as an additive for diesel engines. The performance parameters of the trial were torque, power, BSFC, and BTE. Speed, load, and blend concentration are all considered in this model. Response surface methods and contour plotting with Minitab software were used to generate the prediction model. The results show that the prediction model is within 10% of the experimental data.

Reducing Compaction Temperature of Asphalt Mixtures by GNP Modification and Aggregate Packing Optimization.

Compaction of hot mix asphalt (HMA) requires high temperatures in the range of 125 to 145 C to ensure the fluidity of asphalt binder and, therefore, the workability of asphalt mixtures. The high temperatures are associated with high energy consumption, and higher NOx emissions, and can also accelerate the aging of asphalt binders. In previous research, the authors have developed two approaches for improving the compactability of asphalt mixtures: (1) addition of Graphite Nanoplatelets (GNPs), and (2) optimizing aggregate packing. This research explores the effects of these two approaches, and the combination of them, on reducing compaction temperatures while the production temperature is kept at the traditional levels. A reduction in compaction temperatures is desired for prolonging the paving window, extending the hauling distance, reducing the energy consumption for reheating, and for reducing the number of repairs and their negative environmental and safety effects, by improving the durability of the mixtures. A Superpave asphalt mixture was chosen as the control mixture. Three modified mixtures were designed, respectively, by (1) adding 6% GNP by the weight of binder, (2) optimizing aggregate packing, and (3) combining the two previous approaches. Gyratory compaction tests were performed on the four mixtures at two compaction temperatures: 135 C (the compaction temperature of the control mixture) and 95 C. A method was proposed based on the gyratory compaction to estimate the compaction temperature of the mixtures. The results show that all the three methods increase the compactability of mixtures and thus significantly reduce the compaction temperatures. Method 3 (combining GNP modification and aggregate packing optimization) has the most significant effect, followed by method 1 (GNP modification), and method 2 (aggregate packing optimization).

Preparation and properties of the PLA-based conductive biocomposites with the addition of rGO nanoplatelets

This study was aimed at fabricating PLA-based conductive biocomposites with addition of redox graphene (rGO) nanoplatelets by different processing techniques, such as the masterbatch melting method and the solution mixing method. The effect of two different rGO nanoplatelets on the conductivity of the biocomposites was also discussed. Results of the molecular dynamics simulation showed that, compared with the polycaprolactone (PCL) and poly (ethylene-co-octene) (POE), the thermoplastic polyurethane (TPU) can be a better toughening agent for PLA-based biocomposites, while the addition of rGO may have an adverse effect on the mechanical properties of the PLA-based biocomposites. The volume resistivity of the sodium dodecyl benzene sulfonate functionalized rGO (rGO-SDBS)/PLA composite was lower than that of the rGO/PLA composite no matter what processing technique was used. The solution mixing method was beneficial to improve the conductivity of the composites, and the volume resistivity of the rGO-SDBS/PLA composite fabricated by this technique can be reduced to 10−1 Ω∙m, which can make LED emitting light under normal voltage. Using N-rGO with better conductivity and fewer layers instead of rGO to prepare the composites, the volume resistivity of the N-rGO/PLA composite was reduced to 10−3 Ω∙m. When microcrystalline cellulose (MCC) was continuously introduced into the N-rGO/PLA composite, the volume resistivity increased to 10−2 Ω∙m, and both of which can make LED emitting light under normal voltage.

Response surface methodology to predict the effects of graphene nanoplatelets addition to diesel engine performance

Engine emissions have become one of the major problems of the world today. Therefore, researchers need to find ways to reduce engine emissions. There are many available methods to reduce emissions or improve engine performance such as using an alternative engine or using alternative fuels. The simplest method is by introducing additives to the currently used fuel and engines. Nanoparticles of zinc oxide, titanium oxide, aluminium oxide, and cerium oxide are among the popular additives used by researchers. The results from the research have been very positive, as it successfully reduced engine emissions. However, there are concerns about the toxicity of the emissions that exposed hazards to human health. A few researchers introduced carbon-based nanomaterials as an additive to improve engine performance and reduce engine emissions. The use of carbon-based nanomaterials is very promising since it poses little to no effect on human health. Graphene is a carbon-based nanomaterial used as an additive in this study. This study aimed to forecast the effects of graphene nanoplatelets’ addition to engine performance. The study used torque, power, brake-specific fuel consumption, and brake thermal efficiency as performance parameters. The prediction models consider speed, load, and blend concentration in the calculation. A full-quadratic model with help of Minitab software is used to develop the prediction model. The model is then presented in surface plot and contour plot. The results show that the prediction model agrees with the experimental data with ±10% accuracy. In conclusion, the RSM model of graphene nanoplatelets’ effects on diesel engine performance is producible using full quadratic calculation.

Effect of functionalised and non-functionalised GNPs addition on strength properties of high viscous epoxy adhesive and lap shear joints

This research explores the combinative effects of graphene nanoplatelets (GNPs) addition, functionalisation, and filler concentration on the mechanical behaviour of high viscous structural adhesive (Araldite 2011) and lap shear joints strength. Non-functionalised, carboxylate (COOH) and amine (NH2) functionalised GNPs were mixed in the amounts of 0.25, 0.5, 0.75 and 1 wt% in the host resin by a modified solution mixing technique. Two configurations of lap joints i.e. single lap joint (SLJ) and double lap strap joint (DLSJ) were manufactured using aluminium alloy 5083 adherends. The strength properties of GNPs/epoxy adhesive and lap shear joints were determined by tensile testing. In the case of adhesive, an increase in the value of elastic modulus and tensile strength were observed, accompanied by a decrease in fracture strain. A maximum increase of 13% in the tensile strength and 39% in elastic modulus was observed with the addition of 1 wt% non-functionalised GNP. The lap joints also showed improvement in terms of joint strength with the addition of GNPs. A maximum improvement in failure load of 36% for SLJ and 25% for DLSJ was observed by the inclusion of 0.75 wt% non-functionalised GNP. Optical and Scanning Electron Microscopy (SEM) was utilized for the analysis of fracture surfaces, and the correlation between nano-reinforcement and strengthening mechanisms was critically discussed.

Effect of addition of graphene nanoplatelets on the mechanical properties of triaxially braided composites

Braided composites possess an advantage of good out-of-plane mechanical properties, near net-shape manufacturing, impact and damage resistance. This work aims to investigate the effect of graphene nanoplatelet (GNP) addition on glass fibre triaxial braided composites (TBC). Tensile, flexural, and short beam shear tests were conducted to investigate the mechanical performance of the pristine and hybrid TBC. A numerical model was framed to estimate the material properties of hybrid TBC which were further used as input for the finite element simulation. Results indicate a 15% increase in tensile strength, a 20% increase in flexural strength and a 10% increase in interlaminar shear strength (ILSS). The experimental results were in good agreement with the analytical results. The braided architecture along with proposed GNP combination further enhances mechanical properties and enables gradual failure of the composite which is a desirable property for load bearing structures.

Flexural strength, thermal and dielectric properties of AlN ceramics with BN nanoplatelets addition

The effects of the low-content addition of boron nitride nanoplatelets (BNp) on the microstructure, flexural strength, thermal and dielectric properties of AlN ceramics were studied. X-ray diffraction and microtopography indicated that the platelike BNp phases were detected in the grain boundary, decreasing the grain size of the AlN samples. Flexural strength increased with 0.5 wt% and 1 wt% BNp addition, and such increase was attributed to the smaller grain sizes and the two-dimensional structure bridging mechanism. Comparing the experimental thermal conductivity with the theoretical calculated values, no strong atomic interaction occurred between AlN and BNp, and thermal conductivity slightly decreased with the addition of a suitable amount of BNp. Moreover, the temperature dependence of dielectric spectrum of the samples exhibited a remarkable difference due to the additional polarisation mechanisms caused by the addition of BNp. Overall, suitable addition of BNp can improve flexural strength whilst maintaining the high thermal conductivity and excellent dielectric properties of AlN ceramics.

Effect of graphene nanoplatelets addition in benzoxazine carbon fiber laminates properties

In this work, the effect of graphene nanoplatelets (GNPs) addition in the mechanical, thermal and electrical properties of carbon fiber composites was studied. GNPs were incorporated into benzoxazine matrix and nanocomposites with a 0.5 and 2 wt.% of graphene nanoplatelets were manufactured. The effect of this nanoreinforcement in benzoxazine mechanical properties as well as in its thermal and electrical conductivity was evaluated. Carbon fiber composites has been manufactured by means of liquid resin infusion (LRI) technique using the nanocomposites prepared. The manufacturing process with the nanocomposite containing a 2 wt.% of GNPs presented some filtration problems which hindered its characterization. The laminate with a 0.5wt.% of nanoreinforcement showed an increase in both thermal and electrical conductiviy regading to the panel with unmodified benzoxazine.

Investigation of Effects of Graphene Nanoplatelets Addition on Mechanical Properties of 7075-T6 Aluminium Matrix Hybrid Fibre Metal Laminates

Investigation of Effects of Graphene Nanoplatelets Addition on Mechanical Properties of 7075-T6 Aluminium Matrix Hybrid Fibre Metal Laminates

Improving Fracture Toughness of Tetrafunctional Epoxy with Functionalized 2D Molybdenum Disulfide Nanosheets.

In this work, improved fracture toughness of tetra-functional epoxy polymer was obtained using two-dimensional (2H polytype) molybdenum disulfide (MoS2) nano-platelets as a filler. Simultaneous in-situ exfoliation and functionalization of MoS2 were achieved in the presence of cetyltrimethylammonium bromide (CTAB) via sonication. The aim was to improve the dispersion of MoS2 nanoplatelets in epoxy and enhance the interfacial interaction between nanoplatelets and epoxy matrix. Epoxy nanocomposites with CTAB functionalized MoS2 (f-MoS2) nanoplatelets, ranging in content from 0.1 wt% up to 1 wt%, were fabricated. Modified MoS2 improved the fracture properties (81%) of tetrafunctional epoxy nanocomposites. The flexural strength and compressive strength improved by 64% and 47%, respectively, with 0.25 wt% loading of f-MoS2 nanoplatelets compared to neat epoxy. The addition of f-MoS2 nanoplatelets enhanced the thermomechanical properties of epoxy. This work demonstrated the potential of organically modified MoS2 nanoplatelets for improving the fracture and thermal behavior of tetrafunctional epoxy nanocomposites.

Functionalized graphene nanoplatelets/poly (lactic acid)/chitosan nanocomposites: Mechanical, biodegradability, and electrical conductivity properties

AbstractDifferent contents of functionalized graphene nanoplatelet (FGNP) were incorporated into the blend of poly (lactic acid)/chitosan (PLA/CS) (75/25 wt/wt), and the effect of nanoplatelet addition on mechanical properties, biodegradability behavior, and electrical conductivity of the blend was investigated. The results revealed the proper dispersion of FGNP in the blend, and the nanocomposite containing 3 phr FGNP (PLA75/CS25/FGNP3) demonstrated the finest morphology and the narrowest size distribution. The nanocomposite filled with 3 phr FGNP indicated an improvement of approximately 142% and 261% in tensile strength and Young's modulus, respectively, compared to the neat blend. Moreover, with the addition of 3 phr FGNP to the PLA/CS blend, thermal stability significantly improved. In addition, the study of biodegradability behavior demonstrated that the weight loss rate enhanced over time. From the fifth week onwards, the weight loss rate diminished because of the decrease in the number of degradable functional groups in the nanocomposite. On the other hand, the thermal conductivity of PLA75/CS25/FGNP3 showed an improvement of higher than 12 orders of magnitude compared to the neat blend. In addition, experimental data on electrical conductivity and power‐law model predictions were consistent.

Effect of graphene nanoplatelet addition on the electrical conductivity of poly(hydroxybutyrate-co-hydroxyvalerate) biocomposites

Poly(hydroxybutyrate-co-hydroxyvalerate) (PHBV) is one of the most promising biodegradable polymers used in many applications due to its biodegradability and non-toxicity. However, the usage of PHBV in electronic, biomedical, and biosensor applications has been limited due to its poor electrical properties. This study shows a simple method of producing and enhancing the electrical conductivity of PHBV-based biocomposites by adding graphene nanoplatelet (GNP) as a conductive filler. The biocomposite films were prepared using the solvent casting method, consist of five GNP loading (0-5 wt. %). The prepared PHBV/GNP biocomposites show enhanced electrical conductivity compared to neat PHBV. PHBV/GNP biocomposite with 5 wt. % filler loading exhibits the highest electrical conductivity at 3.83 × 10−3 S/cm. Higher crystalline regions in the PHBV/GNP biocomposites have facilitated the transfer of electrons between PHBV, resulting in the formation of conductive biocomposites, as evident from X-ray diffraction (XRD) characterization.