Clay Nanoparticles Research Articles

An experimental investigation on the flexural and wear properties of multiscale nanoclay/basalt fiber/epoxy composites

AbstractIn this work, multiscale basalt fiber/epoxy composites were fabricated using silane‐modified Na+‐montmorillonite nanoclay, at various contents (0.5, 1, 3, and 5 wt% with respect to the matrix). Flexural and tribological characteristics of the composites were studied. First of all, a silane coupling agent, namely 3‐aminopropyltriethoxysilane (3‐APTS), was applied onto the surface of the nanoclay particles, and then the effects of modified nanoclay on the three‐point bending and wear properties of the basalt fiber/epoxy composites were assessed. Fourier transform infrared spectra indicated that the 3‐APTS coupling agent was successfully grafted onto the surface of the nanoclay particles after modification. The three‐point bending test results demonstrated that the basalt fiber/epoxy composite having 3 wt% modified nanoclay had the highest flexural strength and modulus. On the other hand, the pin‐on‐disk wear test results showed that the multiscale composite containing 5 wt% modified nanoclay had the highest wear resistance. Finally, the fracture and worn surfaces of the specimens were assessed to identify the dominant mechanisms.

Electron Beam Modification on Dielectric, Thermal, and Thermo-mechanical Properties of Styrene Butadiene Rubber/ Clay Nanocomposites

The effect of the surface treatment of clay nanoparticles on the Styrene -butadiene Rubber (SBR) /clay nanocomposite was studied. The treatment process was done by coating the clay by trimethylolpropane tiracrylate (TMPTA) then irradiated by 100 kGy of an electron beam accelerator. Two distinct groups from SBR/ Nano treated and non-treated clay composites were prepared to be compared with each other. The effect of clay nanoparticles loading and treatment process on the rubber was investigated by Dielectric properties, Thermal gravimetric analysis (TGA), thermomechanical analysis (TMA), and volume fraction dependence. It is found that by the addition of clay, there is a decrease in the amorphous contents of the samples owing to the detectable increase in the relaxation time as observed from the dielectric relaxation spectroscopy measurements. The depolarizing factor, calculated by Tasangaris equation indicates the change of the shape of clay particles from oblate ellipsoids to the shape of a sphere with the applied frequency. The activation energy was calculated for all samples and show that it decreases with the treatment process while increased with the increase of the clay. Furthermore, the weight loss has an undulatory behavior with the clay increasing and treatment process.

Preparation of PP/PP-g-MAH/C15A Nanocomposite by Melt Extrusion Process and Comparative Study of its Mechanical and Non-Isothermal Crystallization Behaviour

Nanocomposite films have been prepared by melt blending method with the help of twin screw extruder using polymer polypropylene(PP)nucleating agent like organically modified nanoclay at optimum loading condition. Compatibilizers such as polypropylene grafted maleic anhydride (PP-g-MAH) were used for better compatibility between polymer matrix and filler. The effect of organoclay on nucleation effect and subsequent incremental values in mechanical and thermal behavior of different nanocomposite films has been investigated and explained with justifications. The tensile properties have shown to be improved in presence of clay nanoparticles due to resistance exerted by clay layers against plastic deformation of the polymer. Thermal properties measured by differential scanning calorimeter shows increased crystallization temperature of the nanocomposites in presence of clay particles and compatibilizer of optimum concentration.

Cover Image, Volume 138, Issue 40

The cover image by Muhammad Bilal and colleagues shows an SEM micrograph representing the fractured surface of clay reinforce sulfonated polyimide nanocomposite. The SPI membrane characterizes a homogenous morphology throughout the matrix due to the uniform distribution of clay nanoparticles with no pore or cracks. The uniform distribution and proper dispersion of nanofillers are due to the functionalization of vermiculite clay, as the NH2 group of 3-APTES makes contact through covalent linkage with the SO3H group of SPIs matrix. However, these linkages between organicinorganic moieties might affect the properties of composites film. DOI: 10.1002/app.51310

Sheet-like clay nanoparticles deliver RNA into developing pollen to efficiently silence a target gene.

Topical application of double-stranded RNA (dsRNA) can induce RNA interference (RNAi) and modify traits in plants without genetic modification. However, delivering dsRNA into plant cells remains challenging. Using developing tomato (Solanum lycopersicum) pollen as a model plant cell system, we demonstrate that layered double hydroxide (LDH) nanoparticles up to 50 nm in diameter are readily internalized, particularly by early bicellular pollen, in both energy-dependent and energy-independent manners and without physical or chemical aids. More importantly, these LDH nanoparticles efficiently deliver dsRNA into tomato pollen within 2-4 h of incubation, resulting in an 89% decrease in transgene reporter mRNA levels in early bicellular pollen 3-d post-treatment, compared with a 37% decrease induced by the same dose of naked dsRNA. The target gene silencing is dependent on the LDH particle size, the dsRNA dose, the LDH-dsRNA complexing ratio, and the treatment time. Our findings indicate that LDH nanoparticles are an effective nonviral vector for the effective delivery of dsRNA and other biomolecules into plant cells.

Thermal activity of conventional Casson nanoparticles with ramped temperature due to an infinite vertical plate via fractional derivative approach

With inspired thermal characteristics and dynamic applications of nanoparticles, the researchers are motivated to suggest multidisciplinary significances of nano-materials in various thermal engineering and industrial processes. In this analysis, a mixed free convection nanofluid flowing on a vertical plate is discussed with heat transfer in the drilling of nanofluid. The Casson liquid is assumed as a base fluid with uniform suspension of clay nanoparticles. The leading partial differential governing equations with physical properties of nanoparticles are demonstrated with corporal flow phenomenon and imposed thermal conditions. In the governing partial differential equations, the partial derivative with respect to time is replaced by the most recent definition of fractional derivatives i.e. Atangana-Baleanu time-fractional derivative, and then the solution of temperature and velocity field is found by utilizing the Laplace transformation. The effects of different parameters with different values are deliberated and plotted graphically and numerically for temperature and momentum equations. The main results and conclusions are accomplished at the end of this exertion and compared with existing literature. It is concluded that the velocity profile boost up with Grashof number. The results of temperature and momentum equations show a more decaying tendency as compared to Caputo-Fabrizio fractional derivative.

Synthesis of clay‐armored coatable sulfonated polyimide nanocomposites as robust polyelectrolyte membranes

AbstractHerein, coatable sulfonated polyimide (SPI) and clay‐reinforced SPI membranes SPI‐clay 3%, SPI‐clay 5%, and SPI‐clay 7% were successfully fabricated by one‐step high temperature via direct imidization method. The membranes were cast as a coatable thin film using a solution casting method and grafted vermiculite clay nanoparticle were incorporated into the neat SPI as reinforcement by the sonication method. Three different formulated nanocomposite membranes were investigated using different characterization techniques such as Fourier transform infrared spectroscopy as peaks at 1166 and 1227 cm−1 confirmed successful sulfonation. In Proton (1H) NMR synthesis of SPI confirmed as aromatic proton at 7.3–8.8 ppm depicts successful sulfonation and X‐ray diffraction results confirmed the crystalline structure of clay, as its content increased (7%) clear diffraction peak arises at 6 and 25°. Scanning electron microscopy (SEM) provides information about surface morphology of clay reinforced SPI membranes, and SEM micrographs shown uniform dispersion of clay nanofillers and developed easy transfer of electron. Thermogravimetric analysis was performed to investigate the thermal stability of synthesized films, results of thermographs shown degradation in the range of 510–600°C. Different physicochemical parameters employed and their results show the effectiveness of synthesized clay reinforced SPI membranes. Water uptake (WU%) about 0.96%, hydrolytic about 98 h and oxidative stability up to 80°C, ions exchange capacity about 3.16 mmol/g for synthesized clay reinforced SPI membranes. Measurement regarding Dimensional changes was also investigated and dimensional changes (1.557 ∆t/∆l). All these results reveal that the clay‐reinforced coatable SPI membranes are a promising material for polymer electrolyte membranes to be used in fuel cell energy applications.

Effect of nano-clay addition and heat-treatment on tensile and stress-controlled low-cycle fatigue behaviors of aluminum-silicon alloy: Effect of nano-clay addition and heat-treatment

The objective of the present paper is to investigate the stress-controlled low-cycle fatigue behavior of piston aluminum-silicon (AlSi) alloy reinforced with nano-clay particles and T6 heat-treatment. The piston aluminum-silicon alloy strengthened by 1 wt.% nano-clay particles were prepared by the stir casting method and then subjected to the heat-treatment. The optical microscopy analysis demonstrates that heat-treatment changed the size, morphology, and distribution of silicon phases through the microstructure of the aluminum matrix. In addition to tensile tests, stress-controlled low-cycle fatigue experiments at different loading conditions including the variation of the mean stress, the stress rate, and the stress amplitude were conducted at room temperature. The obtained experimental results showed no clear improvement in either mechanical or fatigue properties of the material. Moreover, the density measurements using the Archimedes method reveal a higher content of the porosity in nano-composite. It was observed that the reinforcement (nano-particles and heat-treatment) can change the cyclic behavior of the AlSi alloy, significantly. The cyclic hardening feature of the AlSi alloy changed to cyclic softening and also the fatigue lifetime and the ratcheting resistance decreased after the nano-particles addition and heat-treatment. Through the microstructural analysis, it was indicated that the neglecting of higher kinematics of age hardening in nano-composite was the major source of mechanical properties reduction. In the end, it was shown that the fatigue lifetime of samples can be described adequately utilizing a modified plastic strain energy technique considering the mean stress effect.

Natural and Synthetic Nanomaterials in Microbial Biotechnologies for Crop Production

Nanoparticles of various materials (up to 100 nm in size) are characterized by a large surface area, which significantly increases their reactive properties. This makes promissing the studies of their possible application in different technologies, including those in the agricultural production sector. This review summarizes the literature on the distribution and properties of natural nanoparticles in the environment. The features of the interaction between various types of microorganisms, nanoparticles of natural minerals, oxides of metals and carbon nanoparticles are analyzed. The review also summarizes the data on the effect of nanoparticles of different origin on microorganisms, plant growth and development. It also presents the information on the effectiveness of the use of clay mineral nanoparticles in the production of complex bacterial preparations for plant growing and the prospects of using nanoparticles of metal oxides in this industry.

Polymeric Coatings for AR-Glass Fibers in Cement-Based Matrices: Effect of Nanoclay on the Fiber-Matrix Interaction

Polymeric coatings are widely used to enhance the load bearing capacity and chemical durability of alkali-resistant glass (AR-glass) textile in cement-based composites. The contact zone between coated yarns and concrete matrix plays a major role to enable the stress transfer and has still to be improved for the full exploitation of the mechanical behavior of the composite. As a new approach, this paper studies how the addition of nanoclay particles in the polymer coating formulation can increase the chemical bond between organic coating and inorganic matrix. This includes the description of the water-based coating preparation by dispersing sodium montmorillonites, whereby the resulting coating nanostructure is characterized by X-ray diffraction and energy dispersive X-ray spectroscopy. Single glass fibers were treated by dip-coating. Atomic force microscopy was used to determine the surface roughness, and the effect on the fiber tensile properties was studied. Moreover, the morphological and chemical characteristics of the coatings were compared with the results obtained from single fiber pull-out (SFPO) tests. It was shown that the incorporation of nanoclays leads to increased interfacial shear strength arising from the ability of nanoclay particles to nucleate hydration products in the fiber-matrix contact zone.

An experimental investigation on the low-velocity impact performance of the CFRP filled with nanoclay

In this study, the effect of the commercial nanoclay Cloisite® 20A on the impact response of the carbon fiber reinforced polymers was investigated using a low-velocity drop-weight impact machine under three impact energy levels of 10 J, 15 J, and 20 J. Contrary to other studies and for more improvement of the properties, clay nanoparticles were dispersed in the resin through solution blending methodology, and laminate samples were fabricated by vacuum infusion process. The optimal percentage of nanoclay was determined by tensile and flexural tests on the epoxy samples containing various nanoclay contents (0.2-0.8 wt.%). For a deeper understanding of the damaged nanocomposites, force-time, force-displacement, and energy-time responses were analyzed. Finally, the influence of nanoclay incorporation by solution blending method and the impact-induced damages were explored by measuring the permanent indentation, radiographic analysis, optical and field emission scanning electron microscopy. Addition of 0.2 wt.% Cloisite® 20A led to a significant increase in the maximum impact force (up to 25.7%), a reduction of the absorbed energy (up to −50.25%), and a decrease in the maximum displacement (up to −29.08%). Moreover, the permanent indentation and the delamination area were significantly decremented compared to the other studies using direct dispersion to disperse nanoclay in the resin matrix. Furthermore, it was revealed that the addition of nanoclay resulted in the transition of the failure mode of carbon fiber reinforced polymer during low-velocity impact from delamination to matrix cracking.

Numerical Investigation of Controllable Parameters Effect on Nanofluid Flooding in a Random Pore Generated Porous Medium

This study simulates the enhanced oil recovery process using nanofluids into a microporous medium. To obtain the optimum values that affect this process, design experiments with the general factorial method was performed. Four parameters included type of nanoparticles and the base fluids, diameter, and volume fraction of nanoparticle were considered. The porous medium was created with the commercial grid generation tool and Fluent software was used to solve the governing equations. Comparison of numerical results with the experimental data illustrates that they are in good agreement. In addition, results show that clay nanoparticles with formation water have the greatest impact on the oil recovery factor compared to other nanofluids. Also the nanofluid with higher amounts of nanoparticles in the base fluid and smaller diameter have better performance in improving the oil recovery factor. Therefore, for having the maximum oil recovery factor, the best combination of parameters is clay nanoparticles with 2 nm diameter and 5 vol. % in formation water.

Evaluation the effect of electricity flow on mechanical and permeability properties of chitosan film containing clay and silver nanoparticles

Evaluation the effect of electricity flow on mechanical and permeability properties of chitosan film containing clay and silver nanoparticles

Optimization of Nanoclay/Polyacrylonitrile Scaffold Using Response Surface Method for Bone Differentiation of Human Mesenchymal Stem Cells.

Response surface methodology (RSM) based on the D-optimal algorithm was employed here for the electrospinning of nanoclay/polyacrylonitrile (PAN) composite scaffold by the aim of obtaining the lower fiber diameter and better mechanical properties for bone regeneration. The input parameters included the electrospinning voltage, flow rate and the ratio of nanoclay/PAN and the obtained values for the optimum point were 17 kV for the applied voltage, 0.41 ml/hr for flow rate, and 19.06% for the nanoclay/PAN ratio. The composite scaffold was fabricated in accordance with these optimum values and then studied by scanning electron microscopy and tensile apparatus. The fiber diameter and Young's modulus of the prepared scaffold were respectively 145 ± 12 nm and 267 ± 8.7 MPa that the values were between predicted by RSM. Moreover, the biocompatibility and osteogenic differentiation of the composite scaffold were evaluated by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide and alkaline phosphatase assays. The bare scaffold and tissue culture polystyrene were used as control groups. The results approved stronger bioactivity and bone regeneration with the composite scaffold as a presence of clay nanoparticles.

Experimental and Numerical Investigation of Tensile and Flexural Behavior of Nanoclay Wood-Plastic Composite.

In this study, the effect of wood powder and nanoclay particle content on composites’ mechanical behavior made with polyethylene matrix has been investigated. The wood flour as a reinforcer made of wood powder was at levels of 30, 40, and 50 wt.%, and additional reinforcement with nanoclay at 0, 1, 3, and 5 wt.%. Furthermore, to make a composite matrix, high-density polyethylene was used at levels of 70, 60, and 50% by weight. Wood-plastic composite (WPC) specimens were manufactured in injection molding. After preparing the specimens, tensile and bending tests were performed on samples. The mechanical properties such as tensile and flexural strength and flexural modulus were measured. Results showed that nanoclay particle content increases flexural modulus, flexural strength, modulus of elasticity, and tensile strength. The experimental test results show that Young’s moduli increased with the volume of wood flour. The biggest modulus of elasticity was achieved in the samples having 50 wt.% of wood powder. Furthermore, the highest value of tensile strength was achieved at the level of 30 wt.%. The highest flexural strength was for the sample containing 50% wood powder by weight. Additionally, a numerical model was made utilizing the Abaqus software using the finite element method (FEM). Comparing the numerical and experimental results, it was found that they are compatible in the linear-elastic and plastic state of the material. There are no crucial differences between experiment and FEM.

Dispersed solar still for effective desalination using montmorillonite nanoparticles for sturdy clean water yield

Abstract Direct Solar Steam Generation (DSSG) system is an emerging technique in the field of desalination for yielding sustainable clean water. This investigation propagates through the use of nanoscale absorbers (montmorillonite) for sturdy desalination because of their excellent photo thermal conversion of nanoparticles. The solar absorber was dispersed in sea water in liquid type rather than fixed or floating type. Nanoparticles of chemical composition were employed by the researchers from starting to the present day, which includes carbon nanotubes, graphene oxide, etc., Inspired by nature and keeping in mind an eco-friendly technique, here we considered montmorillonite clay nanoparticles of natural origin. The experiment was conducted for an operational period of 14 days with a yield of 5.33–6.45 kg/m2/day with an evaporation rate of 0.70, 1.42 and 4.47 kg/m2.hr under 1-, 2- and 4-sun irradiance. The clean water output parameters was validated with WHO standards to satisfy potable water characteristics. The water characteristics before desalination for turbidity, pH, and Cl–, Na+ and TDS were found to be 48.50, 8.7, and 18,400, 12,120, 20,400 mg/L respectively; after desalination they were found to be 0.30, 6.65, 12, 4.5 and 52 mg/L respectively. This work focuses on current water scarcity problem and suggest a way to survival by using naturally available, low cost material.

Corrosion Effects on High‐cycle Fatigue Lifetime and Fracture Behavior for Heat‐treated Aluminum‐matrix Nano‐clay‐composite Compared to Piston Aluminum Alloy

In this research, the corrosion effect has been investigated on the high-cycle fatigue lifetime and the fracture behavior for the heat-treated aluminum-matrix nano-clay-composite and piston aluminum alloys. For this objective, after fabricating stir-casted nano-clay-composite, standard samples were machined and rotary bending fatigue tests were performed. To study the corrosion effect, some specimens were corroded in the 0.00235 % H2SO4 solution after 200 h and then, they were tested under cyclic bending loading. Due to increase in the hardness by adding nano-clay particles and the heat treatment, higher fatigue strength occurred, compared to the base material. Moreover, nano-clay particles shortened the fatigue lifetime; however, this effect was less in the corrosion-fatigue lifetime. In addition, the failure mechanism was the brittle fracture behavior due to the observation of quasi-cleavage and cleavage marks. Experimental data illustrated that the H2SO4 environment effect was effectively significant on the bending fatigue lifetime of the piston aluminum alloy, due to corrosion pits and surface defects. This degradation in material properties was demonstrated as a decreasing shift in both low-cycle and high-cycle fatigue regimes.

Cohesive Zone Modeling of the Elastoplastic and Failure Behavior of Polymer Nanoclay Composites

Cohesive zone model (CZM) is commonly used to deal with the nonlinear zone ahead of crack tips in materials with elastoplastic deformation behavior. This model is capable of predicting the behavior of crack initiation and growth. In this paper, CZM-based finite element analysis (FEA) is performed to examine the effects of processing parameters (i.e., the clay nanoparticle volume fraction and aspect ratio) in the mechanical behaviors of a polymeric matrix reinforced with aligned clay nanoparticles. The polymeric matrix is treated as an ideal elastoplastic solid with isotropic hardening behavior, whereas the clay nanoparticles are simplified as stiff, linearly elastic platelets. Representative volume elements (RVEs) of the resulting polymer nanoclay composites (PNCs) are adopted for FEA with the clay nanoparticle distributions to follow both stack and stagger configurations, respectively. In the study, four volume fractions (Vf = 2.5%, 5%, 7.5% and 10%) and four aspect ratios (ρ = 5, 7.5, 10, and 20) of the clay nanoparticles in the PNCs are considered. Detailed computational results show that either increasing volume fraction or aspect ratio of the clay nanoparticles enhances the effective tensile strength and stiffness of the PNCs. The progressive debonding process of the clay nanoparticles in the polymeric resin was predicted, and the debonding was initiated in the linearly elastic loading range. The numerical results also show that PNCs with stagger nanoparticle configuration demonstrate slightly higher values of the engineering stress than those based on the stack nanoparticle configuration at both varying volume fractions and aspect ratios of the clay nanoparticles. In addition, CZM-based FEA predicts a slightly lower stress field around the clay particles in PNCs than that without integration of CZM. The present computational studies are applicable for processing PNCs with controllable mechanical properties, especially the control of the key processing parameters of PNCs, i.e., the volume fraction and aspect ratio of the clay nanoparticles.

Composite short-side-chain PFSA electrolyte membranes containing selectively modified halloysite nanotubes (HNTs)

Aquivion membrane displays improved properties as compared to Nafion membrane, partly due to shorter side chains. However, some improvements are still necessary for proton exchange membrane fuel cell to operate at low relative humidity. To overcome this drawback, the addition of clay nanoparticle into the Aquivion matrix can be considered. In this study, different composite membranes have been prepared mixing short-side-chain PFSA (perfluorosulfonic acid) Aquivion and selectively modified halloysite nanotubes for PEMFC low relative humidity operation. Halloysites were grafted with fluorinated groups, sulfonated groups, or perfluoro-sulfonated groups on inner or outer surface of the tubes. The obtained composite membranes showed improved properties, especially higher water uptake associated with reduced swelling and better mechanical strength compared to pristine Aquivion membrane and commercially available Nafion HP used as reference. The best performance in this study was obtained with Aquivion loaded with 5 wt% of pretreated perfluoro-sulfonated halloysite. The composite membrane, referred to as Aq/pHNT-SF5, displayed the largest water uptake and proton conductivity among the panel of membranes tested. The chemical stability was not affected by the presence of halloysite in the Aquivion matrix.Graphical abstract

Mixed convection flow and heat transfer of chemically reactive drilling liquids with clay nanoparticles subject to radiation absorption

Impact of radiation absorption on chemically reactive and heat generating drilling liquids comprising of water-clay, kerosene-clay or engineoil-clay nanofluids flowing through a vertical channel is considered. Applications are found in rig drilling process for the convective transport of constituent materials up to the surface by the fluid. It is presumed that the cold and hot parallel walls are maintained at different uniform temperatures, but with unequal slip factors. One of the slippery heated walls is stationary while the other stretches linearly. The partial differential equations are scaled to ordinary equations in tandem with the physical boundary conditions, and evaluated through homotopy perturbation method. Certification is accredited via data comparison with numerical results using shooting method. Among others, the results of this investigation suggest that the concentration and temperature distributions dip due to larger radiation absorption and viscosity parameters with or without the suction, velocity slips, and the chemical reaction parameters.