Influence Of Montmorillonite Research Articles

The influence of montmorillonite on the mineralogical and magnetic changes in magnetite and maghemite during microbial iron reduction

Magnetic iron minerals, such as magnetite (Fe3O4) and maghemite (γ-Fe2O3), are widely distributed in sediments, holding significant potential for reconstructing paleoenvironments through their magnetic properties. However, the impact of microbial iron reduction on the physicochemical and magnetic characteristics of Fe(III)-containing magnetic minerals has recently been recognized as a crucial but often overlooked factor in paleoenvironmental reconstructions. Although magnetic iron minerals are frequently associated with clay minerals in sedimentary settings, our understanding of the influence of clay minerals on the microbial reduction of Fe(III) in magnetic minerals remains limited. To address this knowledge gap, a series of bioreduction experiments were conducted in a non-growth medium, in which lactate acted as the electron donor, magnetite or maghemite nanoparticles (NPs) served as the electron acceptor, and a typical iron-reducing bacterium, Shewanella oneidensis strain MR-1, acted as the reaction mediator, in the presence or absence of montmorillonite (STx-1b). Our results demonstrated that the addition of montmorillonite STx-1b significantly enhanced the dispersion of magnetite and maghemite NPs, thereby increasing the final extent of microbial iron reduction. Moreover, the degree of microbial iron reduction impacted the crystallography and magnetic properties of magnetite and maghemite. Upon bioreduction, the lattice constant, magnetic susceptibility, and the 10-K magnetic coercivity of these magnetic iron minerals exhibited an increase, accompanied by the presence of more structural defects. Specifically, maghemite-magnetite solid solutions were formed in the maghemite-amended biosystems. These findings highlight the influence of clay minerals in natural settings during microbial iron reduction on the magnetic properties of magnetic iron minerals used for paleoenvironmental reconstructions.

The influence of montmorillonite on the flame‐retarding properties of intumescent bio‐based PLA composites

AbstractBiobased flame‐retardant polylactic acid composites were prepared using ammonium polyphosphate (AP), lignin, and a raw montmorillonite (ANa) as the intumescent formulation. The concentration of AP and of ANa was varied in order to study its influence on the flammability properties of the composites. The samples were submitted to cone calorimeter test, thermogravimetric analysis coupled to Fourier‐transform infrared spectroscopy (TGA‐FTIR), limiting oxygen index (LOI), and UL‐94 vertical burn. The cone calorimeter residues were analysed through scanning electronic microscopy, X‐ray diffraction, and FTIR. The results show that the combined addition of the intumescent formulation and the ANa leads to an improvement in the fire behavior of the composites, compared with that of the neat polymer. The best fire‐retardant performance was achieved by using the highest AP concentration (17%) and the lowest ANa concentration (1.2%), reaching a LOI value of 39%.

The influence of montmorillonite on reproductive indicators of laying hens of broiler parental herd

The influence of montmorillonite on reproductive indicators of laying hens of broiler parental herd

Investigation of the Effect of Montmorillonite on the Thermal Properties of Polyvinylpyrrolidone

The influence of montmorillonite (MMT) on the thermal properties of polyvinylpyrrolidone (PVP) was studied by differential thermal and thermogravimetric analyses. It was found that the samples of the montmorillonite-polyvinylpyrrolidone mixture are characterized by higher thermal stability than the sample of pure PVP. It is shown that the degree of increase in the temperature of the beginning of destruction depends on the ratio of the mixture's components. It was found that the composition MMT:PVP = 1:7 has the highest heat resistance (260 °C), while pure PVP begins to degrade at a temperature of 200 °C.

Effects of Clay Mineral Composition on the Dynamic Properties and Fabric of Artificial Marine Clay

Marine clays are easily affected by different mineral composition in cyclic load-based geological hazards. Therefore, based on analyzing the mineral composition of natural marine clay, it is the key to predict the dynamic properties of natural materials under cyclic loading by using quantitated artificial marine clay. In this study, the marine clay found in the South China Sea deltas was investigated. Based on the results of geological conditions and mineral composition analyses, raw non-clay minerals (such as quartz, albite) and clay minerals (such as Na-montmorillonite and kaolinite) were used to produce artificial marine clay, the dynamic properties of which were studied from the impact of mineral composition. Dynamic triaxial laboratory testing for artificial marine clay comprising various clay minerals was performed under identical test conditions. The artificial marine clay with high montmorillonite content exhibited slower development of strain, more sluggish growth in pore water pressure, more rounded hysteresis curves, greater stiffness, and more prolonged viscous energy growth than the clay with low montmorillonite content. In addition, the flocculated fabric of the artificial marine clay with high montmorillonite content demonstrated sufficient pore space changes, more uniform pore distribution, and larger specific surface area than the dispersed fabric of the clay with low montmorillonite content. The factors arising from the influence of montmorillonite may lead to microstructural and fabric changes, hinder the development of pore water, and increase intergranular contact stiffness as well as delay the cyclic strain amplitude at the breakpoint of viscous energy dissipation. In general, the results presented in this study confirm that clay minerals, especially montmorillonite, have significant influence on the dynamic properties of large strain.

Evaluation of reused polyester resin from PET bottles for application as a potential barrier material

Resin systems containing reused polyethylene terephthalate (PET) in their composition were evaluated, as well as the influence of montmorillonite and dolomite for application in plugging and abandonment (P&A) and remedial operations as an alternative material to conventional cementing. The resin compositions were characterized using infrared, with characteristic bands of polyester and styrene monomers being identified in all systems, even with the addition of the thixotropic agent and mineral filler. Compressive strength (CS), rheology, and stability under sedimentation tests were performed. The pure polyester resin showed a CS value above 90 MPa for all curing times. This result is 12 times higher than the minimum required for abandonment operations (7 MPa). All systems presented Newtonian behavior and the addition of 5% dolomite decreased the apparent viscosity. The optimum systems was formulated with 0.1 montmorillonite and 5% dolomite. Based on the results presented, with high compressive strength and low viscosity, the polyester resin proved to be promising for application in well cementing to P&A and remedial operations.

Effects of Montmorillonite and Cane Sugar Composition on The Properties of Montmorillonite-Carbon Sulfonate Catalyst

The influence of montmorillonite and cane sugar mixture with composition of 1:3, 1:2, 1:1, 2:1, and 3:1 to the characteristics of the synthesized montmorillonite-carbon sulfonate composite catalyst had been investigated. The mixture of montmorillonite and cane sugar was carbonized at 400 oC for 15 hours and then sulfonated using sulfuric acid at 175 oC for 15 hours. The presence of sulfonate group was detected using FT-IR and the surface topology of the catalyst was characterized using SEM-EDX. FT-IR spectra showed the existence of sulfonate group at wave number of 1095 cm-1. SEM-EDX analysis showed that the catalyst with the montmorillonite and cane sugar ratio of 1:2 consisted of 1.06% sulfur. The catalyst activity was examined using an esterification reaction between acetic acid and ethanol, and the reaction products were characterized using GC-MS. The chromatogram peak at m/z = 88 confirmed that the product was ethyl acetate. Catalyst with the montmorillonite and cane sugar ratio of 1:2 was shown to have the highest acidity and gave the highest esterification product with 76.97% conversion.

Influence of Montmorillonite and Clinoptilolite on the Properties of Starch/Minerals Biocomposites and Their Effect on Aquatic Environments

This work has analyzed the properties of thermoplastic starch (TPS)-minerals biocomposites and their degradation on water bodies. The TPS-minerals biocomposites were prepared from cassava peels, residual glycerin, and minerals [montmorillonite (MMT) and clinoptilolite (CLI)]. The TPS and TPS-minerals biocomposites were characterized by scanning electron microscopy (SEM), tensile tests, and contact angle measurements. Moreover, microcosm degradation tests evaluated the release of dissolved organic carbon content (DOC) and total nitrogen (TN), carbon/nitrogen ratio (C/N), and heterotrophic bacteria count (HBC) in order to simulate the environmental effects of these biocomposites disposal. The SEM results showed the appearance of whole starch grains in TPS, which is an indicative of a partial thermo-plasticization. Furthermore, it was observed a surface roughness in all samples, with a possible better dispersion of mineral particles for TPS-MMT. This fact indicates an improvement of the tensile strength and elongation at break, when compared to the TPS-CLI. Both TPS-MMT and TPS-CLI presented lower contact angle values than TPS. These characteristics may assist in the microorganism access to the surface, favoring the degradation and the release of carbon and nitrogen. Microcosm degradation tests revealed an increase in DOC release from 18 to 98 mg L−1 for TPS-CLI after 24 h. Besides, there was an increase in TN release to 200% for TPS-MMT and TPS and 500% for TPS-CLI. The HBC presented a high growth after 12 h of contact, especially for TPS (3.4 ± 0.2 log CFU mL−1). Therefore, the TPS-minerals (clinoptilolite/montmorillonite) promoted better surface properties to the biocomposites, by making them biodegradable on aquatic environments, without unbalancing the nutrient loads among different environmental compartments.

Influence of Montmorillonite on the Properties of Silicone Pressure-Sensitive Adhesives: Preparation of a Double-Sided Tape Based on the Best Composition

Silicone pressure-sensitive adhesives were introduced in 1960. They exhibit good properties and are widely used. In this study, the nanofiller montmorillonite was added to such adhesives. Various loadings of this component were tested and their effects on properties such as adhesion, tack, cohesion at different temperatures, viscosity, and the maximum operating temperature were assessed. The adhesive with the optimal loading was selected, tapes were prepared, and the effects of the layer type on the self-adhesive properties were examined. Furthermore, double-sided tapes were fabricated with a new method. In this innovation, the two layers have distinct properties: one is crosslinked twice, the other once. The effects of this approach on the self-adhesive properties of the tapes were analyzed. The low shrinkage value and increased temperature resistance of tapes prepared by loading montmorillonite into pressure-sensitive adhesives demonstrate their potential usefulness in industrial production.

The influence of montmorillonite on the processing and properties of anionic polyamide 6/montmorillonite composites via vacuum assisted resin infusion

In this article, the vacuum assisted resin infusion (VARI) process was employed to prepare anionic polyamide 6/montmorillonite (APA6/MMT) nanocomposites. The ɛ‐caprolactam and MMT mixture are infused into the mold by vacuum. At the same time, the anionic polymerization of ɛ‐caprolactam proceeds all the way which results in fast viscosity rise. To make the VARI process has more practical application value, enough infusion time is necessary. Three types of MMT were chosen in this paper: Na+‐MMT, OMMT‐CTAB, and OMMT‐AUA. In order to study the effects of MMT on infusion process and material's performance, conversion, and temperature test, X‐ray diffraction analysis, transmission electronic microscopy, thermogravimetric analysis, Molau test, and mechanical test were performed. The results indicated that the OMMT‐AUA can both further improve the material's performance and has longer infusion time for VARI process. POLYM. COMPOS., 40:1481–1491, 2019. © 2018 Society of Plastics Engineers

Influence of Montmorillonite Treated with Cetyl Trimethyl Ammonium Bromide Addition in Epoxy-Kenaf Composites

The use of natural fiber as reinforcement in polymer composites has gained importance recently due to environmental concern and its abundance availability from agricultural crops and wood industry [1]. Many advantages offered by natural fibers over synthetic fibers include low density, greater deformability, low cost per unit volume, recyclability and biodegradability [2-3]. In addition, the mechanical properties of natural fibers such as flax, hemp, jute, sisal and kenaf are comparable with glass fiber in respect of strength and modulus [4]. Hence, many studies have been carried out to replace the synthetic fiber for composite preparation.

Influence of montmorillonite on electrical treeing and breakdown characteristics of low-density polyethylene

Electrical treeing is an electrical aging phenomenon that severely threatens the operation safety of power equipment, in which polymer is used as primary insulation material. A type of low-density polyethylene-montmorillonite (LDPE/MMT) nanocomposite was prepared using melt method to study the impact of MMT nanoparticles on the growth of the electrical tree and on the breakdown properties of the LDPE material. The distribution characteristic of space charges of the specimens under DC voltage of –50 kV/mm and short-circuit conditions was measured using pulsed electro-acoustic method. The electrical tree aging characteristics of specimens under AC voltage of power frequency were studied using needle-plate electrode structure test platform. The starting voltage of initiation, the triggering rate, and the growth rate of the electrical trees, as well as the breakdown performance of the specimens under AC voltage of power frequency were measured. The inhibitory mechanism of MMT nano-particles on the growth of electrical trees in nano-composites, and the mechanism behind the improvement of the breakdown strength of the LDPE/MMT specimens were illustrated. Experimental results showed that, the addition of MMT can effectively reduce the amount of space charges injected from electrodes and the accumulation amount in the center of samples. Moreover, space charges dissipated more slowly during short-circuit conditions. The speed and the scale of the growth of the electrical tree declined as the initiation conditions of electrical trees growing in LDPE/MMT nanocomposites increased; meanwhile, the breakdown strength increased substantially. Here are the reasons: MMT can reduce the mobility of carriers in LDPE material, thereby contributing to the improvement of the distribution of space charges. In the meanwhile, MMT changed the development path of electrical trees, and extended the discharge distance. Consequently, MMT postponed the occurrence of penetrable breakdown in the LDPE/MMT specimen, and ultimately improved the breakdown strength of the specimen.

Kaolin/montmorillonite mixtures behaviour on oedometric path and microstructural variations

The aim of this study is to understand and to characterise the influence of the montmorillonite fraction on the behaviour of several mixtures of kaolin and montmorillinite, ranging from pure kaolinite to pure montmorillonite. We show that beyond 35% in weight, montmorillonite is responsible for the global behaviour of the mixture. At the global level, the influence of montmorillonite becomes apparent through the fact that one-dimensional compressibility path, in the (logσ′v-e) plane, loses its linearity. At the local level, MIP results show that the compressibility, for any of the studied mixtures, results in variations in inter-aggregate porosity. The qualitative analysis of SEM images explains the macroscopic behaviour, showing that the more flexible particles of montmorillonite form a structured network surrounding the kaolinite particles. When the percentage of montmorillonite exceeds 35%, the role of this phase becomes major, imposing in particular the particles orientation mechanisms.

Influence of montmorillonite and film processing conditions on the morphology of polyamide 6: Effect on ethanol and toluene barrier properties

Nanocomposite films were prepared by cast extrusion using two chill-roll temperatures from polyamide 6 and an organo-modified montmorillonite. The impact of the nanoclay amount in the range from 0 to 1wt%, as well as the processing conditions on the morphology and transport properties were investigated. The microstructure of the polymer highly depended on the films processing and the presence of the nanoclays. A detailed analysis of ethanol/toluene pervaporation properties was proposed for the all range of ethanol/toluene composition on the basis of thermodynamic and kinetic point of view. The transport mechanism was complex and resulted from a combination of different contributions involving the polymer–permeant and permeant–permeant interactions, the free-volume holes and the amount of γ phase in the crystalline part of the polymer. This study underlined the potentiality of using molecules differing in their interaction as an original way to probe the architecture of these systems.

Influence of montmorillonite on antimicrobial activity of tetracycline and ciprofloxacin

Antibiotics are used not only to fight infections and inhibit bacterial growth, but also as growth promotants in farm livestock. Farm runoff and other farm-linked waste have led to increased antibiotic levels present in the environment, the impact of which is not completely understood. Soil, more specifically clays, that the antibiotic contacts may alter its effectiveness against bacteria. In this study a swelling clay mineral montmorillonite was preloaded with antibiotics tetracycline and ciprofloxacin at varying concentrations and bioassays were conducted to examine whether the antibiotics still inhibited bacterial growth in the presence of montmorillonite. Escherichia coli was incubated with montmorillonite or antibiotic-adsorbed montmorillonite, and then the number of viable bacteria per mL was determined. The antimicrobial activity of tetracycline was affected in the presence of montmorillonite, as the growth of non-resistant bacteria was still found even when extremely high TC doses were used. Conversely, in the presence of montmorillonite, ciprofloxacin did inhibit E. coli bacterial growth at high concentrations. These results suggest that the effectiveness of antimicrobial agents in clayey soils depends on the amount of antibiotic substance present, and on the interactions between the antibiotic and the clays in the soil, as well.

The influence of montmorillonite modification on the properties of composite material based on poly(methacrylic acid)

In this work a new class of functional composites was prepared based on the organically modificated montmorillonite and methacrylic acid. In the first step, the native montmorillonite was mixed with poly(ethylenimine) monomer to promote the intercalation process. In the second step, the methacrylic acid and initiator (potassium persulfate) were added and polymerization was carried out at 80°C for 2 hours. Characterization of the obtained composite material was performed by Fourier transform infrared spectroscopy. The change in interlamellar spacing of montmorillonite after polymer composite preparation was determined by X-ray diffraction. In prepared composite samples the existence of two crystalline phases was estimated by X-ray measurements. In the first, the poly(methacrylic acid) chains are intercalated within the montmorillonite layers, and in the second, they are dispersed in the polymer matrix. The influence of montmorillonite on the thermal properties of the obtained composites was measured using the combined thermogravimetry and differential scanning calorimetry method. The porosity of the prepared samples was determined by isotherm adsorption and the desorption of nitrogen (Brunauer–Emmett–Teller method). It was assessed that a certain amount of polymer is deposited on the montmorillonite and thus covering of the micropores and partially covering of the mesopores was achieved.

Time-varying ionic properties of a liquid-crystal cell

This work investigates time-evolved ionic characteristics of a homogeneously aligned cell composed of a low-resistivity nematic liquid crystal. The influence of montmorillonite as a nanoadditive is studied on the dielectric spectrum of the cell. The incorporation of the inorganic nanoplatelets into the nematic leads to decrease in conductivity in the frequency range from 10 Hz to at least 10 kHz. The dielectric spectroscopic results show that the conductivity, ionic concentration, and diffusion constant of both undoped and doped cells are strongly time-dependent after the cell fabrication.

The influence of montmorillonite and bentonite addition on thermal properties of polyurethanes based on aliphatic polycarbonate diols

Segmented polyurethanes based on hexamethylene-diisocyanate, aliphatic polycarbonate diol and 1,4-butanediol as chain extender were prepared in a bulk by one-step procedure. The structure of elastomeric materials obtained in the form of films and sheets was varied eighter by polycarbonate diol type or chain extender content. The organically modified particles of montmorillonite and bentonite were used as reinforcing fillers. The glass transition temperatures of prepared hybrid materials were determined by modulated differential scanning calorimetry MTDSC. Thermal stability of obtained materials has been studied by thermogravimetry coupled with DSC from an engineering perspective to determine service temperature of prepared elastomeric composites.

The influence of montmorillonite on the anti-reversion in the rubber-clay composites

The influence of organically modified montmorillonate (OMMT) on the curing reversion of natural rubber (NR) and polychloroprene rubber (CR) blend has been demonstrated in this article. Characteristics of the NR/CR/OMMT hybrid composite were undertaken by combining the cure kinetics, thermal stability, and the detection of phase morphology. Compared to the neat rubber blend, thermal gravity analysis has shown improved thermal stability results during degradation for the nanofiller filled ones. Differential scanning calorimetry study has offered cure kinetic results; among which blending with NR has lifted the cure activation temperature of CR low toward. Meanwhile, transmission electron microscopy has shown the intercalation and immobilization of OMMT in the CR phase formed a barrier to NR phase. In addition, to discover the reversion source, infrared spectroscopy has been applied to trace the oxygenic function units in the neat NR vulcanizate. All of the experimental results and related analysis has offered us the base to explain the improvement of the anti-reversion of the rubber blends. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010

Influence of montmorillonite on nucleotide oligomerization reactions: a molecular dynamics study.

We investigate a proposed origins of life scenario involving the clay montmorillonite and its catalytic role in forming oligonucleotides from activated mononucleotides. Clay and mineral surfaces are important for concentrating the reactants and for promoting nucleotide polymerization reactions. Using classical molecular dynamics methods we provide atomic details of reactant conformations prior to polynucleotide formation, lending insight into previously reported experimental observations of this phenomenon. The simulations clarify the catalytic role of metal ions, demonstrate that reactions leading to correct linkages take place primarily in the interlayer, and explain the observed sequence selectivity in the elongation of the chain. The study comparing reaction probabilities involving L- and D-chiral forms of the reactants has found enhancement of homochiral over heterochiral products when catalyzed by montmorillonite.