Clay Nanoparticles Research Articles

Formation of clast-cortex aggregates in experimental fault gouges

Clast–cortex aggregates (CCAs) have been commonly reported in experimental and natural fault gouges. Here we discuss the formation process of CCAs and its mechanical implications, based on experimentally simulated fault gouges. We conducted low- to high-velocity rotary shear experiments on Ca-bentonite gouges at a normal stress of 1 MPa, slip rates of 0.01–1.31 m s−1, and ambient temperature and humidity conditions. The CCAs consist of a central clast (mostly quartz fragments with subordinate clay aggregates) and a concentric rim of nano-clay particles (i.e., cortex). The CCAs range in size from 1 to 100 μm and developed adjacent to a foliated high-strain layer at all slip rates. The microstructures suggest that the CCA-rich layer was mainly deformed by granular flow, whereas the foliated high-strain layer was deformed by cataclastic flow. The increase in average size of the CCAs with displacement and the formation of their concentric rims suggest that the CCAs grew like a rolling snowball. The estimated strain rates obtained from the concentric layers of the CCAs and strain markers indicate the existence of a range of shear strain rates that favors granular flow and the formation and growth of CCAs.

A molecular insight into cracking of the asphaltene hydrocarbons by using microwave radiation in the presence of the nanoparticles acting as catalyst

This research aims to the microwave-assisted catalytic cracking of the asphaltene by using nanoparticles of SiO2, Al2O3, clay, and ZnO acting as a nanocatalyst. The nanoparticle-added oil samples were treated by microwave radiation at the radiation power of 1200 W for 10 min. After extracting the asphaltene, Nuclear Magnetic Resonance (NMR), Fourier Transformed Infrared (FTIR), elemental analysis, Energy-dispersive X-ray (EDX) spectroscopies, and Inductively Coupled Plasma Atomic Emission (ICP-OES) were implemented to characterize the treated asphaltene. Based on the characteristic results, aromatic fused rings have been slightly cracked due to the microwave radiation in the presence of the ZnO and Al2O3 nanoparticles. Besides, the average carbon number of the associated aliphatic chains was reduced to the range of 3.3–3.9 from 5.4 after the microwave radiation. In addition, the microwave radiation in the presence of the nanoparticles reduces the Vanadium and Nickel concentrations of the asphaltenes to 71–90% and 75–93% of the ones in the crude asphaltene, respectively. Based on the indexes, calculated from FTIR spectrums, the asphaltenes are adsorbed on the nanoparticles, leading to absorbing higher microwave energy. By adsorbing the polar functional groups of asphaltene on the nanoparticle, they are heated until the bond cracking, leading to asphaltene release. An analogical insight to the viscometric tests and asphaltene molecular structure showed that the reduction of the electrostatic forces and the Hydrogen interactions are the main reason for the lower tendency of treated asphaltene to aggregate. Based on this study, fine particles, co-producing with crude oil, could catalyze the asphaltene cracking during microwave radiation.

Transparent Composite Films Showing Durable Antifogging and Repeatable Self-Healing Properties Based on an Integral Blend Method.

Antifogging coatings for infrastructures and transparent objects have attracted much attention lately from the perspective of safety and visibility. We have developed a one-pot process to fabricate transparent composite films showing long-lasting antifogging and fast repeatable self-healing properties based on an integral blend (IB) method. This method does not require any specific pretreatments of inorganic fillers/particles. Thus, the precursor solutions could be prepared in a single step by simply mixing raw materials, e.g., poly(vinylpyrrolidone) (PVP) having different molecular weights (MWs: 55, 360, and 1300 k), nano-clay particles (NCPs), and amino-terminated organosilane (AOS). In this study, to control the degree of cross-linking between the PVP matrices and NCPs, addition of AOS as a cross-linker to the PVP matrices (weight percentage of AOS to the PVP matrices, α = 0.01-300%) was carefully controlled. Transparency and self-healing abilities/kinetics of the resulting samples were found to be strongly influenced by both the MWs of PVP and α values. Samples spin-coated with the lowest MW of PVP (55 k) and α values of 0.01-1% gave highly transparent and durable antifogging performance. For example, no fogging was observed for 7 days under >80% relative humidity, and scratches about 30 μm in width could be completely self-healed within a few hours. However, samples with α > 10% gave opaque/grayish films that did not show any self-healing abilities because of an increase in cross-linking of the matrices. The optimized precursor solution was also deposited directly onto the glass slides covered with a transparent porous silica nano-framework (SNF) by a spray-coating method. Due to the formation of the hard and superhydrophilic/hygroscopic SNF with a large surface area, durability of antifogging and self-healing properties of the composite films were moderately improved, compared to those on the flat glass slides.

Morphological investigation of maleic anhydride-grafted nitrile/nanoclay nanocomposites

The dispersion and orientation of three different montmorillonite clay nanoparticles embedded in nitrile-based nanocomposites were examined in the current study. Maleic anhydride was grafted onto a nitrile structure for the purpose of enhancing compatibility, and the resulting nanocomposites were investigated. The grafting of maleic anhydride seemed to have a pronounced effect, leading the structure to a near-exfoliation state. Using energy dispersive x-ray spectrometer, the state of distribution of layered silicate clusters in the nanocomposite was assessed, and it was observed that maleic anhydride provided a reduction in the size of agglomerations and enhanced the homogeneity of the system. The intercalation and delamination of the layered silicates over grafting were validated by transmission electron microscopy. Inter-lamellar spacing measurements were found to correlate perfectly with x-ray data. On the other hand, the alignment of the clay nanoparticles was examined by small angle x-ray scattering. A 3D-orientation approach was developed based on the scattering stereographs.

Piezoelectric activity assessment of size-dependent naturally acquired mud volcano clay nanoparticles assisted highly pressure sensitive nanogenerator for green mechanical energy harvesting and body motion sensing

Over the last few years, there are several methodical and productive ongoing research based on the development of high performing, sustainable, non-hazardous energy harvesting nanogenerators. It is a substantial challenge to construct an energy harvester that has a superior output performance as well as an eco-friendly character. In this work, the utilization of naturally available, biodegradable mud volcano clay from Andaman and Nicobar Islands, India was done to design two simple, portable, cost-effective, biocompatible, eco-friendly piezoelectric nanogenerators (PENGs). In the first place, we developed two types of multifunctional poly-(vinylidene fluoride) (PVDF) thin film incorporated with mortar pestle ground clay nanoparticles (average size of 600–700 nm) for 3 mass% (MP1, MP5, MP10) and ball mill ground nanoparticles (average size of 200–300 nm) for 3 mass% (BM0.5, BM1.0, BM1.5), with large electroactive β crystallinity. The incorporation of clay NPs into the PVDF matrix led to notable nucleation of piezoelectric β crystallite {F(β)} of 80.7% and 84.8% for mortar pestle ground (5% doping) and ball mill ground (1% doping) clay NPs respectively. Using these two multifaceted composite thin films we designed two devices using MP5 (MPENG) and using BM1 (BPENG), which possess good energy harvesting potency, commendable power density values and very fast charging capability. Our MPENG and BPENG generate output voltage of ~ 85 V with a short circuit current of ~ 1.6 μA and output voltage of ~ 125 V with a short circuit current of ~ 1.9 μA, respectively and power densities of 4115 μW/cm3 and 7187 μW/cm3 respectively, on the application of periodic force by hand. The calculated piezoelectric coefficient d33 of MP5 and BM1.0 were 39.75 pC/N and 50.10 pC/N at 50 Hz, respectively. To check the real-life applications, MPENG and BPENG were used to lighten up 25 and 40 no. of blue LEDs when connected a series connection and we charged a 2.2 μF capacitor within few seconds. These nanogenerators could also generate a notable voltage from various body movements like heel pressing, jogging or from vibrations or air flow from various instruments. On further advancement, our proposed devices can be used to power up various self-chargeable portable gadgets in our daily lives and in biomedical fields.

Potential improvements in montmorillonite-nanoclay-modified Cold-Mix Asphalt

Over the years, Cold-Mix Asphalts (CMAs) used principally for pothole patching and partial-depth repairs in Ghana have performed abysmally. Given the convenience, environmental friendliness and low cost associated with CMA production, the use of the material in Ghana is likely to continue for a long time to come. Therefore, to justify it continual use in road maintenance, especially pothole patching, the material must be improved in quality considerably beyond what currently pertains to achieve a more successful product. Fillers used in bituminous mixtures have been identified as having the potential to improve mixture properties positively. In view of this, in the quest to improve CMAs, montmorillonite- nanoclay filler (pulverized clay particles of size 1-100 nm) was incorporated in CMAs formulated from five dense gradation regimes adopted from the Asphalt Institute M-19 Specification. The nanoclay filler was added from 1-3% by weight of aggregate at 1% incremental levels. Using the Marshall Mix Design procedure, mixture properties (Stability, Flow, Optimum Bitumen Content and Voids) were accordingly determined. It was observed that when montmorillonite nanoclay was introduced as a filler in the cold mixes, all the gradation groups recorded improvements in their stability at each nanoclay content. At 2% nanoclay content, all the mixtures yielded optimum values. The increase in stability can be attributed partly to the increase in adhesion between bitumen and aggregate and also partly to the possible increase in inter-particle friction occasioned by the presence of the nanoclay particles which add to the rigidity of the compacted matrix. However, on the contrary, flow values increased significantly. In between the nanoclay contents, from 1-2% and 2-3%, average flow increased by 1.8% and 12%, respectively. The same could be said of the Optimum Bitumen Content which increased for all gradation groups when nanoclay was added. The increase in Optimum Bitumen Content can be said to be accountable for the flow increases realized for mixtures with nanoclay. Even though high stability reflects the bitumen binding strength and the internal friction, a benchmark of the interlocking and friction resistance of aggregates, the high flow values observed are also indicative of the potential susceptibility of the cold mixes to rutting deformation, especially at elevated temperatures.

Application of Bentonite Clay, Date Pit, and Chitosan Nanoparticles as Promising Adsorbents to Sequester Toxic Lead and Cadmium from Milk

Evaluating residual lead (Pb) and cadmium (Cd) levels in food products, especially milk, is critical for product safety and quality. In this purview, the current study aims to determine Pb and Cd concentrations in milk using atomic absorption spectrophotometry and compare their values with international standards. In addition, it aims to remove these metals from milk samples using low-cost, naturally occurring materials, such as bentonite, date pit, and chitosan nanoparticles. The ability of potential adsorbents was also investigated using Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), scanning electron microscopy (SEM), energy-dispersive X-ray (EDX), and transmission electron microscope (TEM). Moreover, their impact on milk’s nutritional properties was considered. The results revealed that most milk samples contained Pb and Cd, with mean values of 0.237 ± 0.179 and 0.041 ± 0.036 mg/kg, respectively. Furthermore, the three possible adsorbents demonstrated high sequestering ability due to their existing functional groups; the adsorption capacity of bentonite to Pb and Cd was 84 and 88%, date pit was 97 and 93%, and chitosan nanoparticles were 82 and 98%, respectively, with no discernible change in milk nutritional contents. In conclusion, the bentonite, date pit, and chitosan nanoparticles were found to be significantly effective and safe in removing hazardous trace elements (Pb and Cd) from contaminated milk.Graphical abstract

First-Principle Colloidal Gate for Controlling Liquid and Molecule Flow Using 2D Claylike Nanoparticles.

Herein, we exploit the natural tendency of two-dimensional (2D) clay nanoparticles to self-assemble and restrict water permeability in soils to fabricate a first of its kind synthetic, pH-activated, reversible, and tunable colloidal flow gate. To realize this, we studied the effect of the pH level of a suspension of claylike layered double hydroxide (LDH) nanoparticles on the LDH coagulation process. We then packed the LDH into a fixed-bed column and examined the effect of pH on mass transport through the column. We found that the 2D platelike LDH particles coagulate in an edge-to-edge configuration, which renders highly nonisotropic aggregates, pivotal for obstructing the transport of liquid and molecules therein. We showed that the coagulation and flow through the column may be regulated by imposing various pH levels as an external stimulus to affect LDH zeta potential. Hence, this work shows that the flow through a column comprising a 2D particle bed can be regulated in a reversible manner by simply alternating the pH of the wash solution, equilibration time, or gate dimensions. Furthermore, we show that, subject to pH treatment, we may open and close the colloidal gate for the transport of large molecules and provide selective transport thereof.

Correlation between Erythrocytes Echinocytic Transformation and Micronucleation in Rodents Exposed to Selected Toxicants: A Preliminary

The genetic constitution and conformational state of living cells are characteristic of building, homeostasis, decay, and apoptosis. Genetic and morphological alterations of red blood cells (RBCs) may influence their survival and function. The purpose of this study was to determine the relation, if any, between the incidence of micronuclei (MN) formation in erythrocytes and their transformations from dissociates to echinocytes or echinocytosis. Two rodents models were exposed in vivo, at various doses and periods, to three environmental agents, physical (Radio Frequency Radiation, RFR), a phytochemical (plant extracts), and geological (Bentonite Nano-clay Particles, BNPs). Microscopic analysis of blood smears stained with Hematoxylin- Giemsa, compared to erythrocytes from unexposed animals, confirmed that the three environmental agents, after long-time exposure, significantly induced MN and increased percentage micronucleated erythrocytes (MNE) as well as the rate of echinocytic transformation. Correlation analysis showed that there were good correlations between erythrocyte micronucleation and echinocytosis. The reason (s) behind this phenomenon is not fully clear at present. We believe that echinocytogenic factors may result in abnormal erythrocytes like echinocytes. The presented data could be an indication that cellular morphological changes may be related to alteration in the genome leading to a common pathway in apoptosis.

Hybrid effect of nanoparticles presence on low‐velocity impact resistance in sandwich panels

AbstractConsidering the massive employment of sandwich panels in multifarious applications, numerous research studies have been conducted on their impact resistance enhancement, one of which, is via simultaneous nanoparticles incorporation including various amounts of silica nanoparticles, clay nanoparticles and carbon nanotubes (CNTs) in to sandwich panels, composed of two glass fiber epoxy composite face sheet and polyvinyl chloride core to render them reinforced. The research objective is to experimentally scrutinize the behavior of nano reinforced sandwich panels under low‐velocity impact test conducted at different energy levels. The damaged areas of the panels were investigated via scanning electron microscopy, the result of which demonstrated that the impact resistance of the sandwich panel can be improved by the integration of nanoparticles. The incorporation of 0.3% of CNT, 1% of nano clay, and 3% of nano silica enhanced maximum contact force by 18.6%, compared to the unreinforced equivalent. Increasing the weight fraction of both CNTs and silica nanoparticles, made contribution to sandwich panels impact resistance increase. The presence of nano clay up to 1 wt% improved the maximum contact force; however, the integration of it into matrix more than 1 wt% led to the reduction of maximum contact force, thus weakened the impact resistance of sandwich panel.

Introducing a new approach to preparing bionanocomposite sponges based on poly(glycerol sebacate urethane) (PGSU) with great interconnectivity and high hydrophilicity properties for application in tissue engineering

In this study, a three-dimensional porous structure of poly(glycerol sebacate urethane) (PGSU) comprising nano-clay and polyacrylic acid (PAAc) was synthesized through a two-step synthesis route. Particulate leaching technique by introducing spun sugar as porogen was also performed as a fabrication method. It was hypothesized that the introduction of spun sugar with its filamentous shape would create interrelated pores required for cell adhesion and proliferation. Polarity, stiffness, and swelling capacity of PGSU would be enhanced by eco-friendly in-situ polymerization of PAAc and the contribution of biocompatible nanoclay. After characterizing the synthesis of PGSU-based scaffolds, viscoelastic behavior, hydrophilicity, and biocompatibility of scaffolds were evaluated. Doubling of swelling capacity in dry state and decrement of water contact angle (WCA) approved the effect of polar carboxyl groups of PAAc in the improvement of polarity and hydrophilicity of PGSU. DMTA results in dry and wet states demonstrated that increasing the concentration of nanoclay and the presence of PAAc chains led to the increase in the storage modulus while the elastic behavior at body temperature was preserved. Eventually, the feasibility of the porous structure of PGSU-based scaffolds in tissue engineering became clear by in vitro biocompatibility test and significant cell adhesion in plasma-treated PGSU/PAAC/nanoclay. Accordingly, introducing clay nanoparticles and in-situ polymerization of acrylic acid, together with porous structure, make PGSU a suitable substrate for cellular interactions.

Long-Range Ionic and Short-Range Hydration Effects Govern Strongly Anisotropic Clay Nanoparticle Interactions.

The aggregation of clay particles in aqueous solution is a ubiquitous everyday process of broad environmental and technological importance. However, it is poorly understood at the all-important atomistic level since it depends on a complex and dynamic interplay of solvent-mediated electrostatic, hydrogen bonding, and dispersion interactions. With this in mind, we have performed an extensive set of classical molecular dynamics simulations (included enhanced sampling simulations) on the interactions between model kaolinite nanoparticles in pure and salty water. Our simulations reveal highly anisotropic behavior, in which the interaction between the nanoparticles varies from attractive to repulsive depending on the relative orientation of the nanoparticles. Detailed analysis reveals that at large separation (>1.5 nm), this interaction is dominated by electrostatic effects, whereas at smaller separations, the nature of the water hydration structure becomes critical. This study highlights an incredible richness in how clay nanoparticles interact, which should be accounted for in, for example, coarse-grained models of clay nanoparticle aggregation.

High‐Efficiency Adsorptive Removal of Phenol from Aqueous Solution Using Natural Red Clay and ZnO Nanoparticles

AbstractPhenol, a highly toxic compound, is a common hazardous chemical. Hence, eco‐friendly and cost‐effective technology for phenol elimination is required. The present study presents a comprehensive study to eliminate phenol compounds via an adsorption technique using ZnO nanoparticles and natural red clay as adsorbents. X‐ray diffraction (XRD), X‐ray fluorescence (XRF), Fourier transform infrared (FTIR), scanning electron microscope (SEM), and Burnauer‐Emmett‐Teller (BET) analyses were conducted for adsorbent surfaces characterization. The impacts of various effects, such as pH and the adsorbent dose on the phenol removal efficiency are described. The results reveal that both ZnO and clay adsorbents removed 99.4 % of phenol at the optimum adsorbent dose of 0.6 g\L and 1 g\L with pH 8 and 2, respectively. The isotherm adsorption data for phenol fitted into Langmuir for the two adsorbents. Yet, the ZnO nanoparticle surface showed a higher capacity (342.72 mg\g) than the natural clay surface (84.01 mg\g). ZnO nanoparticles removed phenol from polluted water at a smaller dose (0.6 g\L) than natural clay (1 g\L). In conclusion, the two adsorbents showed high efficiency in the phenol compound removal.

Adsorption ability evaluation of the poly(methacrylic acid-co-acrylamide)/cloisite 30B nanocomposite hydrogel as a new adsorbent for cationic dye removal

The performance of poly(methacrylic acid-co-acrylamide)/Cloisite 30B nanocomposite (poly(MAA-co-AAm)/Cl30B) hydrogel to adsorb methylene blue (MB) dye from aqueous solutions was investigated and the adsorption efficiency was improved by incorporating Cloisite 30B nanoclays in the adsorbent structure. The hydrogels were analyzed using FTIR, XRD, TGA, and SEM analysis. The effect of adsorbent dose, temperature, initial dye concentration, contact time, and pH on the efficiency of the adsorption process was investigated. Adsorption efficiencies of 98.57 and 97.65% were obtained for poly(MAA-co-AAm)/Cl30B nanocomposite and poly(MAA-co-AAm) hydrogels, respectively. Kinetic study revealed that the adsorption process followed pseudo-first-order kinetic model and α-parameter values of 6.558 and 1.113 mg/g.min were obtained for poly(MAA-co-AAm)/Cl30B nanocomposite and poly(MAA-co-AAm) hydrogels, respectively indicating a higher ability of nanocomposite hydrogel in adsorbing MB-dye. In addition, the results of the intra-particle diffusion model showed that various mechanisms such as intra-particle diffusion and liquid film penetration are important in the adsorption. The Gibbs free energy parameter of adsorption process showed negative values of −256.52 and −84.071 J/mol.K for poly(MAA-co-AAm)/Cl30B nanocomposite and poly(MAA-co-AAm) hydrogels indicating spontaneous nature of the adsorption. The results of enthalpy and entropy showed that the adsorption process was exothermic and random collisions were reduced during the adsorption. The equilibrium data for the adsorption process using poly(MAA-co-AAm)/Cl30B nanocomposite and poly(MAA-co-AAm) hydrogels followed Freundlich and Langmuir isotherm models, respectively. The maximum adsorption capacity values of 32.83 and 21.92 mg/g were obtained for poly(MAA-co-AAm)/Cl30B nanocomposite and poly(MAA-co-AAm) hydrogels, respectively. Higher adsorption capacity of nanocomposite hydrogel was attributed to the presence of Cloisite 30B clay nanoparticles in its structure. In addition, results of RL, n, and E parameters showed that the adsorption process was performed optimally and physically.

Nonlinear static analysis of CNT/nanoclay particles reinforced polymer matrix composite plate using secant function based shear deformation theory

ABSTRACT The mechanically induced nonlinear statical assessment of the bending response of single-walled carbon nanotubes (CNTs) fibers on nanoclay-particle-reinforced polymer hybrid laminated composite plate is explored under static loading conditions. A numerical approach is used to find the mechanical properties of CNT-reinforced hybrid laminated plates prepared by involving nanoclay particles in the existing CNT-reinforced epoxy composites. The transverse nonlinear central deflection of a hybrid nanocomposite subjected to mechanical loading based on the Halpin–Tsai approach is evaluated. For the fundamental formulation, a secant-function-based shear deformation theory (SFSDT) and von Kármán nonlinearity are implemented. The influence of CNT/nanoclay particles over the nonlinear bending responses of the hybrid laminated plate under various loading circumstances is studied in detail. A Newton–Raphson method based on nonlinear finite element technique is used for the hybrid nanocomposite plate. Furthermore, the impact of different design parameters, such as thicknesses of CNT fibers, different interphases along with aspect ratios, stacking sequences under different boundary conditions, and the types of loads on the nonlinear transverse central deflection of CNT/nanoclay-reinforced polymer hybrid composite plate, has been investigated. The effectiveness of the suggested model has been confirmed by comparing it to deflection reactions found in the literature.

Evaluation of thermal degradation behavior and fire resistance performance of wood-plastic composites containing different modified clay nanoparticles

ABSTRACT In this present work, the influence of different clays on the thermal and combustion properties of reed flour (RF) reinforced polyvinyl chloride (PVC) composites were investigated. Firstly, two types of nanoclay, namely layered double hydroxide (LDH) and halloysite nanotube (HNT) were modified with a surfactant before usage. Thereafter, the weight loss, melting temperature, and fire characteristics were evaluated by thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), and cone calorimeter tests. The result revealed the addition of both mLDH and mHNT clays can distinctly enhance the thermal stability of the composites by increasing the decomposition temperature and char residues. The samples including mHNT (32.23%) showed higher residual weight values compared to those of the samples with mLDH (29.82%). DSC data indicated that both the crystallization temperature and melting temperature of the specimens tended to substantially increase in presence of nanoclay. The findings showed that the heat release rate and mass loss rate of the specimens treated with mHNT are respectively reduced by 2.1%, and 7.8% compared to that of mLDH. Both time to ignition and limiting oxygen index values increased approximately 9% as the 5 phc mHNT was incorporated into the specimens as compared with mLDH ones.

Preparation and characterization of a new bio nanocomposites based poly(glycerol sebacic-urethane) containing nano-clay (Cloisite Na+ ) and its potential application for tissue engineering.

Nanocomposites containing clay nanoparticles often present favorable properties such as good mechanical and thermal properties. They frequently have been studied for tissue engineering (TE) and regenerative medicine applications. On the other hand, poly(glycerol sebacate) (PGS), a revolutionary bioelastomer, has exhibited substantial potential as a promising candidate for biomedical application. Here, we present a facile approach to synthesizing stiff, elastomeric nanocomposites from sodium-montmorillonite nano-clay (MMT) in the commercial name of Cloisite Na+ and poly(glycerol sebacate urethane) (PGSU). The strong physical interaction between the intercalated Cloisite Na+ platelets and PGSU chains resulted in desirable property combinations for TE application to follow. The addition of 5% MMT nano-clay resulted in an over two-fold increase in the tensile modulus, increased the onset thermal decomposition temperature of PGSU matrix by 18°C, and noticeably improved storage modulus of the prepared scaffolds, compared with pure PGSU. As well, Cloisite Na+ enhanced the hydrophilicity and water uptake ability of the samples and accelerated the in-vitro biodegradation rate. Finally, in-vitro cell viability assay using L929 mouse fibroblast cells indicated that incorporating Cloisite Na+ nanoparticles into the PGSU network could improve the cell attachment and proliferation, rendering the synthesized bioelastomers potentially suitable for TE and regenerative medicine applications.

Structural, Thermal, Optical, Mechanical, and Antibacterial Properties of PLA/Nanoclay/TiO2 Nanocomposite Films

In this report, Polylactide/Nanoclay/TiO2 nanocomposite films with two different weight percentages (2wt% and 5wt %) of clay and TiO2 nanoparticles were prepared by a cost-effective approach. A solvent casting process with the help of a cost-effective film applicator was used to prepare nanocomposite films. The surface morphology investigations revealed the agglomeration of fillers at higher weight percentages and uniform mixing of fillers at lower weight percentages. The crystallinity of the prepared films did not alter much with the nanofiller addition. Nanofillers with a 2wt% concentration in the PLA matrix enhanced thermal and mechanical properties significantly. The PLA nanocomposite films have exhibited an intense broad emission band in violet color with a wavelength of ≈420 nm. In addition, the antibacterial activity of polylactic acid nanocomposite films was investigated against Gram-positive S. aureus and Gram-negative E. coli bacteria. The enhanced antibacterial activity is observed for a 5wt% concentration of nanofillers. The results showed that the antibacterial activity increases with nanofiller concentration. This study presents a simple and cost-effective approach to preparing nanocomposite films with tuneable properties of mechanical, thermal, and antibacterial activity.

Effect of nanoparticle shape on the mixed convective transport over a vertical cylinder in a non-Darcy porous medium

The current article depicts the mixed convective flow of Graphene oxide and Clay nanoparticles suspended nanofluid in a non-Darcy porous medium considering the effect of the shape of the nanoparticles. The nanofluid utilized in the present study is a drilling fluid, which is mud that circulates in the cylindrical borehole, to enhance the drilling operation efficiency leading to cost effectiveness. The drilling fluid used to lubricate and cool the drill bit, improves the productivity and stability, lifts the cuttings from the bottom of the hole. The current investigation is to improve the efficiency of the drilling fluid. Here the base fluid is considered as water based mud and the nanoparticles are GO and Clay. The spherical and needle shaped nanoparticles are investigated in this study. The basic equations are solved numerically by adopting the shooting technique. It is also noticed that more heat augmentation is seen in the Darcy flow compared to the non-Darcy flow conditions. The results show that a strengthened temperature distribution is noticed with the spherical shaped particles, as the nanoparticle volume fraction increases in the base fluid. The present findings and the findings in the literature have proportionality. The sphere shaped particles have the higher settling rate which helps in drill cutting.

Adsorption of methyl violet dye from wastewater using poly(methacrylic acid-co-acrylamide)/bentonite nanocomposite hydrogels

In this study, nanocomposite hydrogels of poly(methacrylic acid-co-acrylamide) (Poly(MAA-co-AAm)) containing different weight percent bentonite clay nanoparticles (0, 5, 10, and 15 wt. %) were used to remove methyl violet (MV) dye. FTIR, SEM, TGA, and XRD were used to analyze the properties of adsorbents. Results showed that bentonite nanoparticles were successfully distributed in the hydrogel system. Bentonite nanoparticles at 10 wt. % gave the maximum MV dye adsorption efficiency. The highest adsorption was obtained at a pH of 5, an adsorbent dosage of 1.5 g/L, a temperature of 25 °C, a contact time of 60 min, and a pollutant concentration of 10 mg/L. In thermodynamics studies, a negative values of Gibbs free energy (ΔG°) indicating that the adsorption process was spontaneous. In addition, Poly(MAA-co-AAm) hydrogels and Poly(MAA-co-AAm)/bentonite nanocomposite hydrogels gave the adsorption enthalpy (ΔH°) of –61.24 and –36.14 kJ/mol witch shows that the adsorption process is exothermic in the temperature range 25–45 °C using both adsorbents. Langmuir isotherm model was successfully applied in describing the equilibrium behavior of the adsorption process. The kinetic study showed that the pseudo-second-order model was more successful in describing the kinetic behavior of the adsorption process than pseudo-first-order and Elovich models. Poly(methacrylic acid-co-acrylamide) and poly(methacrylic acid-co-acrylamide)/bentonite adsorbents gave the α parameter values of 0.4276 and 22.15 mg.(g.min)−1, respectively indicating the high adsorption capacity of these adsorbents.