Weight Percentage Of Nanoparticles Research Articles

Optimising Nanoparticle Dispersion Time for Enhanced Thermomechanical Properties in DGEBA-Based Shape Memory Polymer Composites

Shape-memory polymers (SMPs) are smart materials that can change shape upon an external stimulus. This phenomenon is called the shape memory effect (SME), which is caused by entropy change due to rapid molecular motion in the polymer segments. Due to the inherently weak thermomechanical properties, use of SMPs is limited in many engineering applications. Therefore, SMPs are often reinforced with fibres and nanoparticles (NPs). NPs offered greater flexibility due to their superior physical, chemical, electrical, mechanical, and thermal properties. However, the homogeneous distribution of NPs is crucial for composition’s stability and enhancement of the base material’s properties. Among the different techniques used for dispersing NPs, ultrasonic irradiation has shown excellent emulsifying and crushing performance. The sonication process is essential for mitigating agglomerates; however, prolonged sonication time probably increases epoxy temperature, micro-bubbles, cavitation, breaking apart molecules and finally degrading the epoxy resin performances. This paper provides critical insight of nanoparticle dispersion into diglycidyl ether of bisphenol A epoxies (DGEBA). DGEBA epoxy resin was added to TiO2 NPs and sonicated for 60 min with 5 min intervals while the temperature of epoxy was maintained below 60oC by using a water cooling throughout the sonication process. The process parameters such as amplitude, mode, epoxy volume and the weight percentage of NPs were kept constant. After each sonication step, Fourier-transform infrared spectroscopy (FTIR) was performed using Thermo Scientific™ and analysed through OMNIC™ Professional quantitation software. In accordance with FTIR results, until 30 min of the sonication, DGEBA resin was not degraded. In order to confirm the performances and the reinforcing effect of NPs, thermo-mechanical and shape memory properties were compared with the neat specimen. The outcomes of this research have suggested quick guidance to find optimum NP dispersion time for DGEBA resins, which has been hardly studied before.

Development and analysis of Fe-doped ZnO nanoparticle-infused sisal fiber reinforced hybrid polymer composites for high-performance sound absorption and thermal insulation applications

In the current study, sisal fiber-reinforced hybrid composites have been developed by integrating a bidirectional mat with a blend of epoxy using Fe-doped ZnO (IDZO) nanoparticles at concentrations of 0.2, 0.4, 0.6, and 0.8 wt%. Hand-lay-up approach was used to create the composites. The composites were characterized through a comprehensive analysis of their density, water absorption, elasticity, thermogravimetric analysis, mechanical resistance, thermal conductivity, microhardness, and propagation of sound properties, including sound absorption coefficients and sound transmission class ratings. As filler loading increased, the bio-composite sample’s hardness increased under the density and void volume fraction values, with 0.8 wt% composite sample showing the superior micro-hardness. A positive correlation was observed between the ZnO nanoparticle weight percentage and thermal conductivity, with improve nanoparticle content leading to improved thermal performance. Composites containing 0.4 wt percent nanoparticles showed superior tensile strength (66.8–84.16 MPa), flexural strength (97.69–120.02 MPa) and flexural modulus (3.56–7.68 GPa). It has been observed that the weight percentage of IDZO filler greatly influences the sound absorption efficiency of the current composites. These findings highlight the promising potential of these novel biocomposites in advanced engineering applications, emphasizing their usefulness in demanding environments with biodegradability and high-performance thermal, mechanical, and acoustic properties. Based on the sound transmission class ratings, the sisal fiber biocomposites have been regarded as great adoptions for use as sound-absorbing materials such as wall partitions, doors, enclosures, and structural components, thermal insulation systems, and electrical insulation.

Fabrication of PMMA nanocomposite biomaterials reinforced by cellulose nanocrystals extracted from rice husk for dental applications

The primary objective of global studies is to develop the properties and durability of polymers for various applications. When it comes to dental disability, denture base materials must have sufficient mechanical and tribological performance in order to withstand the forces experienced in the mouth. This work aims to investigate the effects of the addition of low content of cellulose nanocrystals (CNC) on the mechanical and tribological performance of the polymethyl methacrylate (PMMA) nanocomposites. Different weight percent of CNC (0, 0.2, 0.4, 0.6, and 0.8 wt%) were added to the PMMA matrix followed by ball milling to evenly distribute the nanoparticles reinforced phase in the matrix phase. The findings emphasize the significant impact of CNC integration on the performance of PMMA nanocomposites. By increasing the content of the CNC nanoparticles, the mechanical properties of PMMA were improved. In addition, the tribological outcomes demonstrated a significant reduction in the friction coefficient besides an enhancement in the wear resistance as the weight percentage of nanoparticles increased. The surface of the worn samples was investigated by utilizing SEM to identify the wear mechanisms corresponding to the different compositions. In addition, a finite elment model (FEM) was developed to ascertain the thickness of the worn layer and the generated stressed on the surfaces of the nanocomposite throughout the friction process.

Physical, mechanical characterization, and artificial neural network modeling of biodegradable composite scaffold for biomedical applications

The performance of substitute osteoconductive scaffolds in guiding new bone formation and creating vital biological conditions in living organisms is of crucial importance. In this study, bioresorbable scaffolds were synthesized by incorporating polyvinyl alcohol (PVA) with hydroxyapatite nanoparticles (n-HAP) and Iron oxide (Fe3O4) nanoparticles (NPs) (MNPs) using a freeze-drying technique. Subsequently, the magnetic nanocomposite scaffolds were immersed in a phosphate-buffered saline (PBS) solution for 24 days to assess their degradability percentage. The physicochemical and morphological properties of the magnetic nanocomposite scaffolds were evaluated using Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), and scanning electron microscopy (SEM). Furthermore, the mechanical behavior was examined, while the pore dimensions and porosity were determined using immersion-based techniques. Noteworthy attributes of the magnetic nanocomposite scaffolds were observed, including a maximum swelling capacity of 176 %, a substantial porosity of 72.7%, and impressive mechanical characteristics, such as a compressive strength of 4.61 MPa and an elastic modulus of 2.13 GPa. The degradation study conducted in a PBS solution revealed that the scaffold with the highest n-HAP content (20 wt%) exhibited a degradation rate of approximately 21% after a 24-day period. The influence of environmental conditions, including time, temperature, and salt-containing environments, on the swelling behavior and bio-resorption of the scaffolds was examined. Additionally, an artificial neural network (ANN) was developed to forecast the impact of weight percentages of n-HAP and MNPs on various scaffold properties. According to the ANN predictions, increasing the weight percentages of n-HAP and MNPs resulted in a reduction in pore size, an increase in porosity, and an improvement in the mechanical properties of the scaffolds. Moreover, the incorporation of a higher number of nanoparticles led to increased absorption and swelling, facilitating bone tissue formation. Satisfactory accuracy in predicting scaffold properties was demonstrated through error analysis and linear regression plots, aiding designers in selecting appropriate weight percentages of nanoparticles for future designs. The findings indicate that the synthesized magnetic nanocomposite scaffold closely resembles the physical and mechanical characteristics of natural bone tissue. The utilization of an ANN for performance assessment demonstrated favorable efficiency and effectiveness. Therefore, the significance of the current study lies in the comprehensive investigation of the synthesis and characterization of a biodegradable magnetic nanocomposite scaffold, as well as the utilization of an ANN-based approach to predict and optimize its properties for potential bone tissue engineering applications.

Dielectric and structural properties of polyaniline-tungsten trioxide nanocomposites: For the packing of nano-electronic devices and EMI shielding

Polymer nanocomposites (PNCs) have showed the significant applications in the fields of packing, energy, safety, defense, sensors, EMI shielding, optoelectronics etc. Tungsten trioxide nanoparticles (NPs) were prepared by propellant chemistry technique using Azadirachta indica extracts as a fuel/surfactant. Conducting polyaniline (PANI) was prepared using aniline monomer and suitable polymerizing agents. Ex-situ nanocomposites were prepared by mixing the different weight percentage of NPs into PANI matrix. For the better dispersion of NPs in to the matrix, solvents like Dodesyl benzene sulphonic acid (DBSA) and Camphor sulphonic acid (CSA) were used. Crystal structure, morphological features and their dielectric response at room temperature were reported. Electromagnetic Shielding (EMI) studies were compared between the PANI-WO3 composites prepared by CSA and DBSA solvents. Composites showed worthy shielding response of 80 dB with CSA and 38 dB with DBSA. Here, the protonation of the solvent and the dispersion of NPs with the polymer matrix matters for the shielding efficiency. Hence, prepared materials are suitable for packing of electronic devices which provides the better EMI shielding and also suppress the heat through effective absorption of EM waves of X-Band.

Thermal stability and decomposition kinetics of polybenzoxazine and oligomeric polyhedral octaphenyl silsesquioxane nanocomposites

AbstractIn this study, the impact of octaphenyl polyhedral oligomeric silsesquioxane (POSS) on the thermal stability of polybenzoxazine resin at 1, 3, and 5 wt% POSS loading through dynamic thermogravimetric analysis (TGA) at heating rates of 10, 20, 30 and 40°C min−1 was investigated. Besides, the decomposition kinetics of polybenzoxazine resin (PBZ) and various nanocomposites were studied using Kissinger, Friedman, Flynn‐Wall‐Ozawa (FWO) and Coats‐Redfern (CR) models and also, the activation energies of samples were calculated. At first, benzoxazine monomer was synthesized and then nanocomposites were prepared via solution mixing method. The qualitative dispersion of nanoparticles in benzoxazine resin was examined through the utilization of scanning electron microscopy and x‐ray diffraction experiments. The results showed that the addition of nanoparticles improved the thermal stability of PBZ resin specially at 1 wt% POSS loading and at higher POSS content the thermal stability of the resin decreased. As determined by TGA, the char yield of resin was enhanced by 2.6% upon the addition of 1 wt% nanoparticles. In addition, in 1 weight percent of nanoparticles, as the heating rate rose from 10 to 40°C min−1, the Integral Program Decomposition Temperature (IPDT) has increased by about 260°C, and this increase is about 183°C compared to the resin, and also elevating the heating rate, Td (5%) and Td (10%) weight loss of samples shifted to higher temperatures. The degradation mechanism of the resin and nanocomposites was evaluated through Kissinger, Friedman, FWO and CR models. The results displayed that the addition of 1 wt% nanoparticles increased the activation energy (Ea) values of the nanocomposites compared to that of neat resin and above this filler content, the Ea values decreased. The findings derived from the FWO model indicated that the inclusion of a 1 wt% filler raised the Ea values of the first and second stages of PBZ resin decomposition from 136–200 and 151–214 kJ mol−1 to 148–210 and 180–228 kJ mol−1, respectively.

Experimental exploration of nano-phase change material composites for thermal management in Lithium-ion batteries

The present study reports an experimental investigation carried out for the thermal management of cylindrical lithium-ion battery simulators using aluminum oxide (nano particle)-eicosane (phase change material) composites. The experiment involves varying the power input from 4 to 10 W in 2 W increments and adjusting the weight percentage of nanoparticles (wt%) from 0.5 to 0.9 in 0.2 wt% intervals. The examination of battery temperature evolutions in response to heating power, a comprehensive heat transfer analysis incorporating the Nusselt number, the determination of the maximum temperature difference, thermal resistance analysis, and the exploration of temperature variations in the absence of Phase Change Material (PCM) are considered. The results show that an increase in the weight percentage of alumina nanoparticles in phase-change material cannot always improve the thermal performance. The results of the present study give guidelines for designing battery thermal management systems. The power levels used in the experiment vary from 4 W to 10 W in steps of 2 W. For a power level of 4 W, the heat flux is 1.088 kW/m2, and for a power level of 10 W, the heat flux is 2.72 kW/m2.

3D and 4D Printing of PETG-ABS-Fe3O4 Nanocomposites with Supreme Remotely Driven Magneto-Thermal Shape-Memory Performance.

This study introduces novel PETG-ABS-Fe3O4 nanocomposites that offer impressive 3D- and 4D-printing capabilities. These nanocomposites can be remotely stimulated through the application of a temperature-induced magnetic field. A direct granule-based FDM printer equipped with a pneumatic system to control the output melt flow is utilized to print the composites. This addresses challenges associated with using a high weight percentage of nanoparticles and the lack of control over geometry when producing precise and continuous filaments. SEM results showed that the interface of the matrix was smooth and uniform, and the increase in nanoparticles weakened the interface of the printed layers. The ultimate tensile strength (UTS) increased from 25.98 MPa for the pure PETG-ABS sample to 26.3 MPa and 27.05 MPa for the 10% and 15% Fe3O4 nanocomposites, respectively. This increase in tensile strength was accompanied by a decrease in elongation from 15.15% to 13.94% and 12.78%. The results of the shape-memory performance reveal that adding iron oxide not only enables indirect and remote recovery but also improves the shape-memory effect. Improving heat transfer and strengthening the elastic component can increase the rate and amount of shape recovery. Nanocomposites containing 20% iron oxide demonstrate superior shape-memory performance when subjected to direct heat stimulation and a magnetic field, despite exhibiting low print quality and poor tensile strength. Smart nanocomposites with magnetic remote-control capabilities provide opportunities for 4D printing in diverse industries, particularly in medicine, where rapid speed and remote control are essential for minimally invasive procedures.

Studies on the Mechanical, Strengthening Mechanisms and Tribological Characteristics of AA7150-Al2O3 Nano-Metal Matrix Composites

Stir-casting with ultrasonic cavitation produced nano-Al2O3-filled AA7150 matrix composites in this study. The SEM microstructure study shows that all composites include nano-Al2O3 particles with consistent particle sizes and homogenous distribution. EDS and XRD showed no secondary phases or impurities in the composite. Optical microscopy showed intense ultrasonic cavitation effects, and nano-Al2O3 particles caused grain refinement in the AA7150 matrix. The composite’s mechanical characteristics improved when the Al2O3 nanoparticle weight percentage (wt.%) increased. With only 2.0 wt.% nano-Al2O3 particles, the composites yielded 232 MPa, 97.52% higher than the sonicated AA7150 matrix alloy. Multiple models were used to characterize the strength of the AA7150 nano-Al2O3 composite. The findings showed that thermal incongruity, Orowan strengthening, the Hall–Petch mechanism, and load transfer effects contributed the most towards the increased strength of the composite. Increasing the nano-Al2O3 wt.% in the AA7150 matrix improved hardness by 95.08%, yield strength by 90.34%, and sliding wear resistance by 46.52%. This enhancement may be attributed to the combined effects of better grain refinement, enhanced dispersion with dislocation strengthening, and better load transfer between the matrix and reinforcement, which are assisted by the inclusion of reinforcements. This result was confirmed by optical studies.

Tribological and morphological properties of bentonite nano‐clay/CaCO3 reinforced high‐density polyethylene nanocomposites

AbstractElastomeric polymers such as high‐density polyethylene, have a variety of desirable features, that have supplanted traditional materials. However, high‐density polyethylene (HDPE) shows inadequate wear resistance, which limits its use for industrial applications, particularly in low‐load‐bearing applications such as flexible energy harvesting devices and sensors. The current work is engrossed in investigating the influence of hybrid reinforcements CaCO3 particles and bentonite nano clay as secondary reinforcements in high‐density polyethylene (HDPE)‐based composites on the wear and friction properties. The reinforcements were melt compounded with HDPE using a Brabender mixer and sampled using an injection molding machine. The wear test (ASTM G‐99‐04) was performed by a pin‐on‐disk tribo‐tester. In comparison to a base matrix, the synthesized hybrid composite achieved the maximum improvement in wear rate of 93%. The results revealed that there is a significant improvement in wear resistance. Morphological analysis revealed that due to the encapsulation and compatibilization effect of bentonite nano clay the hybrid composite exhibited improved wear performance. The results signify the synergistic effect of filler particles resulted in sufficient bonding for stress transfer due to the encapsulation of CaCO3 by nano clay. The wear mechanism observed optically was abrasion, fatigue, and adhesion wear that changed with the change in the weight percent of nanoparticles. Finally, the prepared composite with enhanced tribological properties such as low wear rate, low friction coefficient, and enhanced morphology can be used in low load‐bearing wear applications such as turbo nanogenerators and piezo nanogenerators.Highlights Bentonite nano clay and CaCO3 dispersed homogeneously in HDPE matrix. Wear resistance of HDPE increases by reinforcing particles (nano‐clay and CaCO3). Micro‐cutting, deformations, and particle husks were the possible wear mechanism. Encapsulation effects the hybrid composite to exhibit improved wear performance.

Evaluation of Physical Properties of Denture Base Resins Containing Silver Nanoparticles of Aloe barbadensis Miller, Morinda citrifolia, and Boesenbergia rotunda and Its Anti-microbial Effect: An In Vitro Study.

Introduction The denture bases fabricated from polymethylmethacrylate (PMMA) have some disadvantages, such as surface prone to microbial growth and biofilm accumulation, which contributes to the onset and dissemination of infections among denture wearers. Therefore, the purpose of this in vitro study was to evaluate the flexural strength, hardness, and antimicrobial effect of denture base resin incorporated with 0.05% and 0.1% silver nanoparticles (AgNPs) of Aloe barbadensis miller (aloe vera), Morinda citrifolia (noni), and Boesenbergia rotunda (finger root). Materials and methods A total of 84 PMMAsamples were used and were divided into three groups. Flexural strength tests were performed on Group 1 PMMAblocks. Group 2 involved hardness testing of PMMAblocks, whereas Group 3 involved antimicrobial activity. Each group was subsequently split into seven subgroups with differing concentrations of AgNPs: Sub Group 1: control (no AgNPs),Sub Group 2: 0.05% aloe vera AgNPs, Sub Group 3: 0.1% aloe vera AgNPs, Sub Group 4: 0.05% noni AgNPs, Sub Group 5: 0.1% of noni AgNPs,Sub Group 6: 0.05%finger root AgNPs, and Sub Group 7: 0.1% finger root AgNPs.The flexural strength was evaluated usinga universal testing machine (Instron 8801). Surface hardness was measured using a Vickers tester (Tukon 1102). For the antimicrobial activity analysis, the samples were incubated in a suitable culture broth containing Candida albicans for 24 hours. Microbial colony count (colony-forming unit (CFU)/mL) was estimated to evaluate the microbial adhesion to the surface of the denture base materials. Statistical analysis The flexural strength, hardness, and CFU between the groups were analyzed using one-way analysis of variance (ANOVA) followed by multiple comparisons with Tukey's honest significant difference (HSD) test (α=0.05). The level of statistical significance was determined at p<0.05. Results It was observed that the mean flexural strength was maximum in PMMA incorporated with 0.05% of aloe vera AgNPs and least in PMMA incorporated with 0.1% noni AgNPs. It was seen that a steady loss in flexural strength is observed from 0.05% to 0.1%. The mean hardness was maximum in PMMA incorporated with 0.1% of noni AgNPs and least in PMMA incorporated with 0.05% aloe vera AgNPs. It was also found that the hardness was directly proportional to the number of nanoparticles. With an increase in the weight percentage of nanoparticles, a steady increase in hardness was seen in all the test groups. In our study, the results showed that finger root 0.1% showed the least CFU with a significant reduction of C. albicans adherence; therefore, it indicates higher anti-fungal activity. Aloe vera 0.05% showed the lowest inhibition of C. albicans,suggesting the least anti-fungal activity. Conclusion Within the limitations of this study, It can thus be concluded that the addition of AgNPs incorporated with plant extracts of Aloe barbadensis miller (aloe vera), Morinda citrifolia (noni), and Boesenbergia rotunda (finger root) can alter the flexural strength, hardness, and microbial adhesion of PMMA. In our study, it can be concluded that flexural strength increases with the addition of AgNPs of 0.5% concentration after which a steady loss is seen. However, the hardness and antimicrobial activity increased with an increase in the concentration of AgNPs in all three plant extracts.

Evaluating the effect of poly (amidoamine) treated bioactive glass nanoparticle incorporated in universal adhesive on bonding to artificially induced caries affected dentin

BackgroundThe purpose of this study was to evaluate remineralisation and its effect on microtensile bond-strength of artificially induced caries affected dentin (CAD) when treated with a commercial universal adhesive modified with poly(amidoamine) dendrimer (PAMAM) loaded mesoporous bioactive glass nanoparticles (A-PMBG).Material and methodsMesoporous bioactive glass nanoparticles (MBG) were synthesised using sol–gel process, where PAMAM was loaded (P-MBG) and added to commercial adhesive at different weight percentages (0.2, 0.5, 1 and 2 wt%). First, rheological properties of commercial and modified adhesives were evaluated. The effect of remineralization/hardness and microtensile bond-strength (MTBs) of those samples that mimicked the rheological properties of commercial adhesives were evaluated using Vickers hardness tester and universal testing machine respectively. Scanning-Electron microscope was used to visualize failed samples of MTBs and remineralization samples. Both evaluations were carried out at 1-,3 and 6-month intervals, samples being stored in stimulated salivary fluid during each time interval.ResultsAddition of nanoparticles altered the rheological properties. With increase in the weight percentage of nanoparticles in commercial adhesive, there was significant increase in degree of conversion, viscosity and sedimentation rate (p < 0.05). The 0.2 and 0.5 wgt% groups closely mimicked the properties of commercial adhesive and were evaluated for remineralization and MTBs. After 6 months, 0.2wgt% group showed increased MTBs (p < 0.05) and 0.5wgt% group increased remineralization/hardness (p < 0.05).ConclusionThe complex of PAMAM-MBG-Universal adhesive can remineralize the demineralised CAD thereby improving its bond-strength when evaluated for up to 6-months.

Influence of TiO2 and Y2O3 nanoparticles on mechanical properties of aluminium matrix hybrid nanocomposites fabricated by vacuum die casting

Purpose The purpose of this paper is to evaluate the effect of titanium oxide (TiO2) and yttrium oxide (Y2O3) nanoparticles-reinforced pure aluminium (Al) on the mechanical properties of hybrid aluminium matrix nanocomposites (HAMNCs). Design/methodology/approach The HAMNCs were fabricated via a vacuum die-assisted stir casting route by a two-step feeding method. The varying weight percentages of TiO2 and Y2O3 nanoparticles were added as 2.5, 5, 7.5 and 10 Wt.%. Findings Scanning electron microscope images showed the homogenous dispersion of nanoparticles in Al matrix. The tensile strength by 28.97%, yield strength by 50.60%, compression strength by 104.6% and micro-hardness by 50.90% were improved in HAMNC1 when compared to the base matrix. The highest values impact strength of 36.3 J was observed for HAMNC1. The elongation % was decreased by increasing the weight percentage of the nanoparticles. HAMNC1 improved the wear resistance by 23.68%, while increasing the coefficient of friction by 14.18%. Field emission scanning electron microscope analysis of the fractured surfaces of tensile samples revealed microcracks and the debonding of nanoparticles. Originality/value The combined effect of TiO2 and Y2O3 nanoparticles with pure Al on mechanical properties has been studied. The composites were fabricated with two-step feeding vacuum-assisted stir casting.

Eco-friendly production of cellulosic fibers from Scots pine wood and sustainable nanosilver modification: A path toward sustainability

This study presents a novel approach for the production of cellulosic fibers from scots pine wood and their subsequent surface modification with greenly synthesized silver nanoparticles (AgNPs), leading to remarkable color effects and improved functionalities, particularly enhanced thermal stability. The size distribution of the scots pine fiber (SPF)materials was determined through sieve analysis, revealing a conversion of scots pine particles from 1.25 mm to 0.8 mm in size. The AgNPs were biosynthesized in situ on the wood fibers using the same fiber as a sustainable stabilizing and reducing agent. Scanning electron microscopy (SEM) was employed to investigate the morphologies of the control and AgNP-deposited samples, indicating a uniform distribution of nanosilver on the coated surfaces of the SPF material. The concentration of synthesized AgNPs on SPF was quantitatively measured using X-ray fluorescence (XRF) tests, ranging from 4149 ± 43 to 6329 ± 55 parts per million (PPM) depending on the AgNP concentration. The weight percentage of nanoparticles was determined by SEM-mediated energy-disruptive X-ray (EDX) analysis. Additional analyses, Fourier transform infrared spectroscopy (FTIR) test was also conducted. Thermal stability tests demonstrated an improving trend correlated with increasing nanosilver loading in the modified SPF materials. The coefficients of variation (R2) exhibited a significant relationship between nanosilver loading and most color parameters. Overall, this research presents a pioneering approach for the eco-friendly production of cellulosic fibers from scots pine wood and sustainable synthesis of AgNPs onto defibrated fibers, thus establishing a new benchmark for sustainable manufacturing processes.

A study to determine electromagnetic interference‐shielding effectiveness on bio‐based polyurethane foam reinforced with PVDF/MgO/Ni for emerging applications

AbstractThe main objective of this study is to prepare nanoparticles‐induced bio‐based polyurethane foam to shield electromagnetic interference (EMI) radiation in the 8–12 GHz frequency range and compare the experimental result with optimization and simulation. Polyvinylidene fluoride (PVDF), magnesium oxide (MgO), and Nickel (Ni) nanoparticles were induced into bio‐based PU (polyurethane) foam through absorption and hydrothermal reduction technique, which includes mechanical stirring, compressing, heating and evaporating. The design of experiment (DOE) methodology was used to find nanoparticle weight percentage (wt%). EMI shielding effectiveness of the bio‐based PU foam composite was measured using Vector Network Analyzer (N5230A PNA‐L). The weight percentages of the optimized sample were predicted using the response surface methodology (RSM), in which the central composite design (CCD) employed the weight percentages of the three nanoparticles as input and the results of the electromagnetic interference shielding effectiveness (EMI SE) experiment as the response output. The result from CCD showed that 3 wt% of PVDF, 10 wt% of MgO, and 1 wt% of Ni gave a maximum EMI SE of 27.78 dB. Then a confirmation sample was created for the same, and EMI SE was estimated empirically. The results obtained for the confirmation sample are 27.56 dB. Then, a scanning electron microscope image was taken for the confirmation sample to analyze nanoparticle‐induced bio‐based PU foam's structural properties. The SEM image with dxf format is imported into the radio frequency (RF) module to calculate the EMI SE through COMSOL Multiphysics. The simulated EMI SE for the confirmation sample was 25.1 dB.

Optical Microstructure, FESEM, Microtensile, and Microhardness Properties of LM 25-B4Cnp-Grnp Hybrid Composites Manufactured by Selective Laser Melting

The current investigation, nano-multi-powder particles, 5 and 10 wt.% boron carbide (B4C) and graphite (Gr) are utilized as a reinforcement, and aluminium LM 25 alloy is used as a matrix. These hybrid nanocomposites were fabricated by a novel additive manufacturing method—selective laser melting. The specimen was carried out in a cylindrical size having 2 circular slots of dimension 14 and length 50 mm. The diverse SLM specimens focused on tribological properties of impact, creep, tensile, and hardness were carried out for the three specimens with same weight percentage of nanoparticles. The consequence of the reinforcement has been performed through microtensile and microhardness tests. The microtensile and microhardness properties are evaluated by microtensile test machine and Vickers hardness tester, and the specimen has been prepared as per ASTM E8 and ASTM E18 standards. Microtensile strength and hardness were augmented by the addition of B4C and graphite nanoparticles. The tensile strength and hardness values are 668.93 MPa and 739.16 MPa, and 193VHN and 206.79VHN, respectively. The result of the microstructure study shows homogeneous dispersion of B4Cnp-Grnp in the matrix material of the LM25 alloy. The FESEM image results of the ruined surface illustrate the addition performance of ductile fracture, brittle fracture, and ploughing of reinforced material. The consequences of the research enhanced tensile and hardness properties of composite with reinforcement added.

Green Flame-Retardant Composites Based on PP/TiO2/Lignin Obtained by Melt-Mixing Extrusion.

Nowadays, highly flammable and harmful plastic materials are used in many daily applications. To prevent burning of materials, other harmful molecules or materials that are not environmentally friendly are added to plastics. To overcome this environmental issue, new materials have been investigated. Lignin, an industrial by-product, is an abundant biopolymer that can be used in fire safety plastics; it is considered a renewable and readily available resource. In this work, PP–TiO2/lignin composites were obtained with TiO2/lignin mixtures through the melt extrusion process, with different weight percentages of nanoparticles (10, 20, 25, and 30 wt.%). The PP–TiO2/lignin composites were characterized by XRD, FTIR, TGA, and SEM. Furthermore, cone calorimetry tests and the mechanical properties were evaluated. Cone calorimetry tests revealed that the introduction of 25 wt.% TiO2–lignin to the PP matrix reduced the peak of heat release rate (PHRR) and total heat release (THR) by 34.37% and 35.45%, respectively. The flame retardancy index (FRI) values of the composites were greater than 1.0 and were classified as good; the highest value of 1.93 was obtained in the PP-30 sample. The tensile tests demonstrated that the flexural modulus of the composites increased gradually with increasing lignin and TiO2 content, and the flexural strength decreased slightly. The use of lignin in PP composites can be an excellent alternative to synthesize new materials with improved flame-retardant properties and which is friendly to the environment.

Performance analysis of lauric acid embedded with nanoparticles as phase change materials in heat transfer applications

Phase change materials can be the most suitable way to enhance the thermal performance of a heat exchanger, and it is one of the important parameters for various developments in renewable energy and engineering applications for a sustainable future. At the time of phase change, the phase change material can store energy and release that stored energy in the form of heat. It is an eminent candidate for different engineering sectors, including thermal, electronics, civil, and textile. In this research, we used lauric acid as a phase change material and copper oxide, aluminium oxide as nanoparticles experimentally. The characterisation tests such as Thermogravimetric analysis, Fourier Transform Infrared Spectroscopy, Ultraviolet-visible, Thermal Conductivity, X-Ray Diffraction, Field Emission Scanning Election Microscope were carried out on the phase change materials and nano phase change materials. The phase change materials are tested individually to analyse the heat transfer rate of the heat exchanger for a specific period of time at three different inlet temperatures. The thermal conductivity of the phase change material is improved by the addition of copper oxide and aluminium oxide nanoparticles to it. By adding Aluminium oxide and copper oxide nanoparticles to the lauric acid, the heat storage capacity is increased by 16.52%, 38.89% at 60°C, 17.75%, 41.33% at 70°C, and 22.67%, 46.17% at 80°C respectively. Copper oxide is the most suitable nanomaterial to improve the thermal conductivity of low thermal conductive phase change materials, since it has properties like high thermal conductivity, low thermal interface resistance, and high aspect ratio. The heat energy stored in phase change materials is increased due to the addition of nanoparticles. In future, a suitable optimization technique can be employed to predict the optimum nanoparticle weight percentage to get improved thermal performance.

Thermal conductivity of water base Ni-np@MWCNT magnetic nanofluid

Thermal conductivity behavior of a nanofluid constructed from encapsulated nickel nanoparticles inside multiwall carbon nanotubes (Ni-np@MWCNT) under various conditions of weight percentage, base fluid temperature as well as external magnetic field was studied experimentally. Ni-np@MWCNT nanoparticles were made by chemical process and various analyses such as XRD, VSM and TEM were implemented for characterizing their properties. The thermal conductivity of Ni-np@MWCNT nanofluid at different conditions of the nanoparticles weight percentage was surveyed as we found that there is an almost regular relevance between the increase in thermal conductivity and the concentration of nanoparticles of the nanofluid. We also investigated the role of nanofluid temperature as an effective parameter in thermal conductivity as we found a relative growth of thermal conductivity in all considered samples with increasing temperature. The results also show that the magnetic field can dramatically control the thermal conductivity of Ni-np@MWCNT nanofluids. The outcomes obtained in this work can be used to produce smart devices based on magnetic nanofluids.

Investigating optimal region for thermal and electrical properties of epoxy nanocomposites under high frequencies and temperatures

This research investigates the optimal region to achieve balanced thermal and electrical insulation properties of epoxy (EP) under high frequency (HF) and high temperature (HT) via integration of surface-modified hexagonal boron nitride (h-BN) nanoparticles. The effects of nanoparticle content and high temperature on various electrical (DC, AC, and high frequency) and thermal properties of EP are investigated. It is found that the nano h-BN addition enhances thermal performance and weakens electrical insulation properties. On the other side, under HF and HT stress, the presence of h-BN nanoparticles significantly improves the electrical performance of BN/EP nanocomposites. The EP has superior insulation properties at low temperature and low frequency, whereas the BN/EP nanocomposites exhibit better insulation performance than EP under HF and HT. The factors such as homogeneous nanoparticle dispersion in EP, enhanced thermal conductivity, nanoparticle surface modification, weight percent of nanoparticles, the mismatch between the relative permittivity of EP and nano h-BN, and the presence of voids in nanocomposites play the crucial role. The optimal nanoparticle content and homogenous dispersion can produce suitable EP composites for the high frequency and high temperature environment, particularly solid-state transformer applications.