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AbstractThis study was performed to evaluate the adsorptive properties of bentonite. Natural bentonite was found to adsorb considerable amounts of Salicylic acid (SA) after modification by hexadecyltrimethylammonium bromide (HDTMA). Batch studies investigated the adsorptive properties of the modified natural bentonite (organobentonite). The characterization results show the increase in the d001 spacing from 1.13 to 1.53 nm for raw bentonite and organobentonite, respectively. The FTIR analysis indicates the asymmetric vs. (CH2) and symmetric vs. (CH2) stretching modes for clay loaded with surfactant molecules are 2919 and 2845 cm−1, respectively. We investigate parameters such as contact time, pH, temperature, and initial concentration. Desorption and regeneration were also studied. The kinetic analysis shows that the adsorption equilibrium of salicylic acid onto organoclay was reached after 120 min and fits well to a pseudo-second-order kinetic model with the contribution of intraparticular diffusion. In addition, the adjustment of the isothermal models indicated that the Langmuir-Freundlich model best fit the isotherms data for unmodified bentonite and the Langmuir model for modified bentonite. The maximum adsorption capacity of organobentonite is 128 mg g−1 at 25 °C. According to the statistical physics model, the SA could be adsorbed on the surface of organoclay in a non-parallel orientation. The desorption-regeneration investigation revealed that the material could be successfully reused for three cycles of SA adsorption. Mechanistic studies of SA sorption on organobentonite have highlighted several mechanisms: hydrogen bonding, electrostatic attraction, and hydrophobic interaction. [ABSTRACT FROM AUTHOR]

AbstractPickering Emulsions are commonly applied in the pharmaceutical, food, and chemical industries. The use of natural particles as stabilizers provides access to surfactant-free dispersions with reduced toxicity and environmental impact. This work investigates the use of three commercial organoclays (C15A, C10A, and C30B) and hydrophilic sodium montmorillonite (Mt) as stabilizers for Pickering emulsions. Emulsion stability was evaluated through macroscopic and microscopic morphological observations and the emulsion microstructure was characterized by optical microscopy and DLS measurements to assess creaming and coalescence. The influence of different experimental parameters on emulsion stability was evaluated, including organoclay content, emulsification time, emulsification speed, and oil–water ratio. The results showed that emulsions based on C15A exhibit better stability against coalescence as compared to emulsions prepared with the other clays. This was attributed to the wettability of the particles and solution viscosity. Droplet size decreased as emulsification time and stabilizer content increased and reached a minimum value at 1 wt.% of C15A and for emulsification time of 5 min and oil–water ratio O/W (v/v: 50/50). The experimental parameters also impacted emulsion viscosity, increasing it for high clay content and as the stirring speed and emulsification time increased. The results of the heat and cold resistance stability tests indicated that 25 °C represents the optimal storage temperature for the prepared emulsions. [ABSTRACT FROM AUTHOR]

The field of asymmetric organocatalysis has witnessed significant advancements in recent years, with chiral urea and thioureas emerging as powerful catalysts. In this study, we aimed to design novel polyurea‐polyurethane nanocomposites functionalized with cinchona urea groups, incorporating organoclay and graphene oxide, to serve as heterogeneous organocatalysts in asymmetric synthesis. The synthesis of these polyurea‐polyurethane nanocomposites was achieved through a two‐component polycondensation reaction. The resulting chiral polyurea‐polyurethanes (PU‐PURs) exhibited favorable yields and demonstrated precise control over stereochemistry, resulting in high enantioselectivity. The incorporation of nanocomposites, such as CU‐MMT and graphene oxide (GO), significantly enhanced the catalytic performance of the PU‐PURs. The CU‐MMT nanocomposites exhibited higher catalytic activity, while the PU‐PURs/GO still exhibited enantioselectivity greater than 99 %. Overall, this study highlights the potential of these novel polyurea‐polyurethane nanocomposites as efficient and versatile heterogeneous organocatalysts in asymmetric synthesis. [ABSTRACT FROM AUTHOR]

Porous clay heterostructures are a hybrid precursor between the pillaring process and organoclays. In this study, the organoclay was substituted by an aluminium intercalated species clay or pillared alumina clays. A porous clay heterostructure was successfully achieved from an aluminium intercalated species clay, due to the easy exchange of the aluminium species by the cosurfactant and silica species. However, using alumina pillared clays, the porous clay heterostructures were not formed; the alumina species were strongly attached to clay sheets which made difficult their exchange with cosurfactant molecules. In this case, the silica species were polymerized and decorated the surface of the used materials as indicated by different characterization techniques. The specific surface area of the porous clay heterostructure material reached 880 m2/g, and total pore volume of 0.258 cc/g, while the decorated silica alumina pillared clays exhibited lower specific surface area values of 244–440 m2/g and total pore volume of 0.315 to 0.157 cc/g. The potential of the synthesized materials was evaluated as a basic blue-41 dye removal agent. Porous clay heterostructure material has a removal capacity of 279 mg/g; while the other materials exhibited lower removal capacities between 75 mg/g and 165 mg/g. The used regeneration method was related to the acidity of the studied materials. The acidity of the materials possessed an impact on the adopted regeneration procedure in this study, the removal efficiency was maintained at 80% of the original performance after three successive regeneration cycles for the porous clay heterostructure. The Langmuir isotherm characteristics were used to propose a single-stage batch design. Porous clay heterostructures with a higher removal capacity resulted in a decrease in the quantities needed to achieve the target removal percentage of the BB-41 dye from an aqueous solution. [ABSTRACT FROM AUTHOR]

Water based polylactic acid (PLA)‐surface modified montmorillonite (MMt) nanocomposites as biobased formulations for paper coating were successfully developed using emulsification solvent evaporation method. Electrostatic and steric stabilization mechanisms have contributed to the production of stable emulsions up to 5 months at 23 ± 1°C, revealing strong repulsive forces generated between the nanoparticles as confirmed by zeta potential (ζ) and dynamic light scattering (DLS) analysis. MMt particles were fully encapsulated by PLA as demonstrated by transmission electron microscopy (TEM) micrographs. Meanwhile the film formation process highlighted the importance of emulsifier's type and solubility in the polymer matrix, as no films were obtained when sodium oleate was used alone compared with continuous, homogeneous, and free‐standing films obtained when the combination Tween 80 (80 wt%)—sodium oleate (20 wt%) was used. Scanning electron microscopy (SEM) micrographs of the cross‐section's surfaces showed homogeneous dispersion of the MMt particles with no clusters or agglomerates formed. Thermal analyses using differential scanning calorimetry and thermogravimetric analysis (DSC‐TGA) showed an overall reduction in the glass transition temperature (Tg) and the thermal stability of neat PLA, whoever this reduction was recovered when MMt was added due to the confinement effect. Thickened PLA and PLA/MMt emulsions using 1 wt% xanthan gum showed a non‐Newtonian behavior and shear thinning flow with suitable viscosity values for paper coating applications. Highlights: Development of stable PLA/organoclay nanocomposite aqueous dispersions.Steric and electrostatic mechanisms provided excellent stability.Full encapsulation of organoclay platelets in nanometric PLA particles.Formation of free‐standing films from PLA/organoclay emulsions.Thickened PLA/organoclay emulsions using Xanthan gum for paper coatings. [ABSTRACT FROM AUTHOR]

This work combines experimental and computational modeling studies for the preparation of a composite of metformin and an organoclay, examining the advantages of a Tunisian clay used for drug delivery applications. The clay mineral studied is a montmorillonite-like smectite (Sm-Na), and the organoclay derivative (HDTMA-Sm) was used as a drug carrier for metformin hydrochloride (MET). In order to assess the MET loading into the clays, these materials were characterized by means of cation exchange capacity assessment, specific surface area measurement, and with the techniques of X-ray diffraction (XRD), differential scanning calorimetry, X-ray fluorescence spectroscopy, and Fourier-transformed infrared spectroscopy. Computational molecular modeling studies showed the surface adsorption process, identifying the clay–drug interactions through hydrogen bonds, and assessing electrostatic interactions for the hybrid MET/Sm-Na and hydrophobic interactions and cation exchange for the hybrid MET/HDTMA-Sm. The results show that the clays (Sm-Na and HDTMA-Sm) are capable of adsorbing MET, reaching a maximum load of 12.42 and 21.97 %, respectively. The adsorption isotherms were fitted by the Freundlich model, indicating heterogeneous adsorption of the studied adsorbate–adsorbent system, and they followed pseudo-second-order kinetics. The calculations of ΔGº indicate the spontaneous and reversible nature of the adsorption. The calculation of ΔH° indicates physical adsorption for the purified clay (Sm-Na) and chemical adsorption for the modified clay (HDTMA-Sm). The release of intercalated MET was studied in media simulating gastric and intestinal fluids, revealing that the purified clay (Sm-Na) and the modified organoclay (HDTMA-Sm) can be used as carriers in controlled drug delivery in future clinical applications. The molecular modeling studies confirmed the experimental phenomena, showing that the main adsorption mechanism is the cation exchange process between proton and MET cations into the interlayer space. [ABSTRACT FROM AUTHOR]

Adsorptive nanofiber electrospun membranes (ANEMs) show promise for heavy metal removal, particularly in dilute solutions. Nanofibrous polyacrylonitrile (PAN) membranes incorporating Cloisite 20A (C20) organoclay were fabricated via electrospinning for As(V) removal. The impact of C20 on structural properties and As(V) removal efficiency of the nanofiber membranes was investigated. The results indicated that the PAN‐C20 membranes morphology was uniform, with fiber diameters mostly falling within the 100–300 nm range. Incorporation of C20, especially in an exfoliated structure, led to increased hydrophilicity, mechanical strength, and roughness of the membranes. Batch adsorption results revealed that the adding C20 up to 1.5 wt.% significantly enhanced adsorption capacity due to the higher concentration and proper C20 dispersion. Dynamic filtration showed that the PAN‐C20(1.0) membrane achieved over 90% As(V) removal efficiency for 960 min and demonstrated excellent regeneration ability. Highlights: Cloisite 20A organoclay was incorporated into PAN by electrospinning to prepare adsorptive membrane.Adsorptive membranes were used for As(V) removal from water.Type of Cloisite 20A dispersion in PAN in dynamic filtration was more important than in static adsorptionPAN‐C20‐1.0 with exfoliated structure showed higher removal efficiency than PAN‐C20‐1.0 with intercalated structure.PAN‐C20‐1.0 membrane was usable for multiple adsorption–desorption cycles. [ABSTRACT FROM AUTHOR]

At the Gowanus Canal Superfund site in Brooklyn, New York, a multilayer reactive capping system is required as part of the approved remedy. The base reactive layer is an organoclay (OC)–sand layer containing a minimum of 25% by dry weight OC that is intended to block any upwelling mobile nonaqueous phase liquids (NAPLs). The construction quality assurance (CQA) method for verifying the OC content of the OC–sand stockpiles prior to placement in the canal consists of Loss on Ignition (LOI) testing performed at an offsite laboratory with a turnaround time of 3 days. To mitigate construction delays, rapid field testing methods to verify the OC content of the OC–sand blends were sought. Interestingly, electrical conductivity (EC) measurements on the as-is (not sieved or pulverized) OC, sand, and their blends provided several correlations with goodness of fit (R2) values >0.95 for a variety of sand-sized materials including: a commercial playground sand, beach sand, a limestone quarry sourced sand, and the sediment capping sand from the first Remedial Target Area (RTA-1) at the Gowanus Canal. The correlation curves and R2 values were relatively insensitive to change in the sand borrow source (silicate or karst geology or salinity). EC measurements were available in as little as 30 min and up to approximately 24 h using a tabletop pH/EC probe, distilled water, beaker, and magnetic stirrer. The EC approach and preliminary correlations presented here can greatly reduce CQA testing turnaround times to within hours (not days) in field settings. Lastly, similar findings were made when another commercially modified bentonite clay known as Fluorosorb-400™ was blended with playground sand. [ABSTRACT FROM AUTHOR]

Highlights This study is dedicated to the fabrication of acrylated epoxidized natural rubber (AENR)/dual‐functionalized organoclay (DF‐C30B) hybrid networks using an in‐situ light‐induced crosslinking polymerization technique. The process begins with the successful synthesis of DF‐C30B, which contains methacrylate groups, achieved by reacting 3‐methacryloxypropyltrimethoxysilane (MPS) with cloisite 30B (C30B). During fabrication, DF‐C30B nanolayers are dispersed within the AENR matrix at various feed ratios, ranging from 1 to 8 parts per hundred of rubber (phr). The photocrosslinking polymerization is then initiated using 2,2‐dimethoxy‐2‐phenylacetophenone (DMPA) as the photoinitiating agent. Subsequent analysis of the nanocomposites involves evaluating their structure and morphology using established techniques such as Fourier transform infrared (FTIR) spectroscopy, x‐ray diffraction (XRD), thermogravimetric analysis (TGA), and transmission electron microscopy (TEM). The FTIR analysis enables comparing distinct bands of the nanocomposite's components, affirming the integration and covalent attachment of nanoclay in the AENR matrix. Results from TEM and XRD illustrate the uniform distribution of DF‐C30B throughout the AENR matrix without significant agglomeration. TGA results indicate that the hybrid networks exhibit enhanced thermal stability, with degradation onset temperatures of 306°C, 308°C, 315°C, and 318°C for DF‐C30B loadings of 1, 2, 4, and 8 phr, respectively, compared to 198°C for pure AENR. Correspondingly, char residue levels increased to 4.3%, 5.6%, 7.8%, and 11.7% for the respective DF‐C30B contents. This research underscores the promising role of DF‐C30B as a strengthening component in nanocomposites based on NR, contributing to improved thermal endurance, enhanced uniformity, and offering insightful directions for future advancements. Fabricated acrylated epoxidized natural rubber (AENR)/dual‐functionalized organoclay (DF‐C30B) hybrid networks via light‐induced crosslinking polymerization. Enhanced compatibility and performance of DF‐C30B within the AENR matrix. Successful integration and stability confirmed by Fourier transform infrared spectroscopy, x‐ray diffraction (XRD), transmission electron microscopy (TEM), and thermogravimetric analysis (TGA). Uniform dispersion of DF‐C30B within the matrix demonstrated by XRD and TEM. Improved thermal stability compared to neat AENR, as evidenced by TGA results. [ABSTRACT FROM AUTHOR]

In this work, a magnetic cross-linked chitosan-benzil/organoclay/Fe3O4 biocomposite (CHI-BZI/OC/Fe3O4) was synthesized as a bio-adsorbent for the removal of remazol brilliant blue R (RBBR) dye from aquatic environment. The adsorption factors i.e., CHI-BZI/OC/Fe3O4 dosage, pH, and time were statistically optimized using the Box-Behnken design (BBD). The highest RBBR removal efficiency of 90.9% was achieved at a CHI-BZI/OC/Fe3O4 dosage of 0.1 g/100 mL, initial solution pH of 4.0, and contact time of 20 min. The RBBR adsorption onto the CHI-BZI/OC/Fe3O4 matched the pseudo-second-order kinetic (PSO). Moreover, equilibrium study was conducted and the best fit to the adsoption expsrimantal data was described by Langmuir isotherm model. The adsorption capacity of CHI-BZI/OC/Fe3O4 for RBBR was determined to be 102.9 mg/g. This work contributes to the advancement of environmentally friendly and sustainable methods for treating dye-contaminated water, showcasing the potential of biocomposite materials as effective adsorbents in the field of water purification. [ABSTRACT FROM AUTHOR]

This study focuses on polyamide 6/organo-modified montmorillonite (PA6/OMMT) nanocomposites as potential liner materials, given the growing interest in enhancing the performance of type IV composite overwrapped hydrogen storage pressure vessels. The mechanical properties of PA6/OMMT composites with varying filler concentrations were investigated across a temperature range relevant to hydrogen storage conditions (−40 °C to +85 °C). Liner collapse, a critical issue caused by rapid gas discharge, was analyzed using an Ishikawa diagram to identify external and internal factors. Mechanical testing revealed that higher OMMT content generally increased stiffness, especially at elevated temperatures. The Young's modulus and first yield strength exhibited non-linear temperature dependencies, with 1 wt. per cent OMMT content enhancing yield strength at all tested temperatures. Dynamic mechanical analysis (DMA) indicated that OMMT improves the storage modulus, suggesting effective filler dispersion, but it also reduces the toughness and heat resistance, as evidenced by lower glass transition temperatures. This study underscores the importance of optimizing OMMT content to balance mechanical performance and thermal stability for the practical application of PA6/OMMT nanocomposites in hydrogen storage pressure vessels. [ABSTRACT FROM AUTHOR]

The current study investigates the production of organoclay suitable for use in the base section of a passenger tire with a cap/base tread construction. The process involved the purification and modification of two types of sodium bentonite clay with different mineral characteristics and ion exchange capacities using a single-step process. The modification process of purified bentonite suspensions was performed using a two-tailed long-chain alkyl quaternary ammonium salt surfactant, namely di (hydrogenated tallow alkyl) dimethyl ammonium chloride (AD2HT), and two one-tailed long-chain alkyl quaternary ammonium salt surfactants, namely cetyl-trimethylammonium chloride (CTAC) and octadecylamine chloride (ODA), in relatively low amounts of surfactant (0.95 CEC), along with polyethylene glycol (4% clay) as an auxiliary modifier. X-ray diffraction (XRD) showed that the interlayer spacing of organoclays significantly increases. In addition, the XRD pattern depends on the kind of surfactant and is independent of the type of bentonite clay. The resulting organoclays were added to the tread base section of a passenger tire using the melt masterbatch technique along with a silane coupling agent. An increase in curing maximum torque (8–15%), curing delta torque (6–14%), hardness (2–10%), static modulus 300 (2–18%), and dynamic storage modulus (11–30%) of the rubber composites was observed without significant change of resilience and loss factor of the composite at 2 Phr of organoclay loadings. The organoclays based on the AD2HT modifier exhibited better mechanical properties than those based on the ODA and CTAC surfactants. The dynamic storage modulus of composites increased by about 30% with only 2 Phr of AD2HT-modified bentonites. Furthermore, the performance of the organoclay was found to be independent of the primary particle size, iron content, and ion exchange capacity of the bentonite clay within the studied range. [ABSTRACT FROM AUTHOR]

Injection moulded specimens were produced from biodegradable poly(butylene succinate) (PBS)/organomodified montmorillonite (OMMT) nanocomposites, after melt compounding in different compositions. WAXD studies demonstrated that the OMMT formed similar intercalation levels in the 2.5–10 w/w% additive ratio range. It was also proved by rotational rheometry that the nanoclay stacks form physical network above 5 w/w% concentration, which significantly influence the viscoelastic properties of the melt. The value of zero shear viscosity also changed accordingly, starting to increase above 5 w/w% nanoclay content. The OMMT content reduced the creep sensitivity measured in molten state.X-ray and DSC investigations showed that OMMT inhibits the crystallisation of PBS, resulting in a decrease in crystallinity at higher nanoclay ratios. As a result, the room temperature creep increased with the OMMT ratio.The Young's modulus linearly increases in the entire concentration range exceeding 1.2 GPa at 10 w/w% nanoclay content. The value of yield strength does not change significantly (35–40 MPa), but the strain at yield – which characterises stiffness – and the notched Izod impact strength already decrease at 2.5 w/w% OMMT content, but further increasing the nanoclay content has minor effect. However, the nanocomposite with 10 w/w% OMMT can be a real alternative to polypropylene (PP) and high-density polyethylene (HDPE) injection moulded products based on its mechanical properties.To characterise the effect of OMMT on dynamic mechanical properties, the S (Stiffening effectiveness), L (Loss effectiveness) and D (Damping effectiveness) indices were introduced to quantitatively describe the nanoclay effect intensity in each temperature range.

In this study, a nanohybrid based on montmorillonite (oMMT2) was prepared through a two‐step method using Arquad MCB‐80 and 9,10‐dihydro‐9‐oxa‐10‐phosphaphenanthrene‐10‐oxide (DOPO) as intercalation agents. The nanohybrid exhibited a basal spacing of 31.5 Å, which contained approximately 12.3% of Arquad MCB‐80 and 31.6% of DOPO. Various amount of oMMT2 nanohybrid was incorporated into a flame‐retardant polyethylene system containing aluminum trihydroxide and red phosphorus with a constant total additive content of 20 wt%. The dispersibility of oMMT2 in the composite matrix was evaluated by energy dispersive x‐ray mapping and x‐ray diffraction analyses. At a content of 3 wt% in the nanocomposite, oMMT2 showed a highly exfoliated state, while at a 5% content, a partially exfoliated and intercalated state was observed. A synergistic flame‐retardant effect between the nanohybrid and the mixture of aluminum trihydroxide and red phosphorus was found. The nanocomposite loading 3 wt% oMMT2 demonstrated the best flame retardancy, achieving a V‐0 rating of the vertical burning test with a limiting oxygen index of 27.6%. Moreover, the addition of the low oMMT2 contents (≤3 wt%) improved the mechanical properties of the flame‐retardant composite. [ABSTRACT FROM AUTHOR]

Two series based on poly(propylene 2,5-furandicarboxylate)-block-poly(tetramethylene oxide) (PPF-b-F-PTMO) containing carbon and mineral nanofillers that differ in shape (1D and 2D) were synthesized via in situ polymerization. The influence of the addition of the 1D-type nanoparticle, i.e., carbon nanofibers (CNFs) and halloysite nanotubes (HNTs), and the so-called 2D-type, i.e., graphene nanoplatelets (GNPs) and organoclay (C20A), on the properties of a biobased block copolymer was analyzed. The dispersion of nanoadditives in the nanocomposites was determined using a scanning electron microscope (SEM). The thermal properties were studied employing differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA). The introduction of nanoparticles increased the crystallinity (Xc) and the mean values of tensile modulus (E) of the bionanocomposites. In turn, one observed that the decrease in the limited viscosity number (LVN) was visible along with incorporating nanoadditives. The synthesized polymer bionanocomposites reveal the mechanical properties of elastomers during mechanical testing. Moreover, the good processability of the obtained materials by injection molding combined with the comprehensive ability to change mechanical and thermal properties of PPF-b-F-PTMO by tailoring the type and content of the nanofillers can indicate their possible applications in packaging, automotive, sports, construction, and many other industries. [ABSTRACT FROM AUTHOR]

Pultruded fiber reinforced polymer composites used in civil, power, and offshore/marine applications use fillers as resin extenders and for process efficiency. Although the primary use of fillers is in the form of an extender and processing aid, the appropriate selection of filler can result in enhancing mechanical performance characteristics, durability, and multifunctionality. This is of special interest in structural and high voltage applications where the previous use of specific fillers has been at levels that are too low to provide these enhancements. This study investigates the use of montmorillonite organoclay fillers of three different particle sizes as substitutes for conventional CaCO3 fillers with the intent of enhancing mechanical performance and hygrothermal durability. The study investigates moisture uptake and kinetics and reveals that uptake is well described by a two-stage process that incorporates both a diffusion dominated initial phase and a second slower phase representing relaxation and deterioration. The incorporation of the organoclay particles substantially decreases uptake levels in comparison to the use of CaCO3 fillers while also enhancing stage I, diffusion, dominated stability, with the use of the 1.5 mm organoclay fillers showing as much as a 41.5% reduction in peak uptake as compared to the CaCO3 fillers at the same 20% loading level (by weight of resin). The mechanical performance was characterized using tension, flexure, and short beam shear tests. The organoclay fillers showed a significant improvement in each, albeit with differences due to particle size. Overall, the best performance after exposure to four different temperatures of immersion in deionized water was shown by the 4.8 mm organoclay filler-based E-glass/vinylester composite system, which was the only one to have less than a 50% deterioration over all characteristics after immersion for a year in deionized water at the highest temperature investigated (70 °C). The fillers not only enhance resistance to uptake but also increase tortuosity in the path, thereby decreasing the overall effect of uptake. The observations demonstrate that the use of the exfoliated organoclay particles with intercalation, which have been previously used in very low amounts, and which are known to be beneficial in relation to enhanced thermal stability, flame retardancy, and decreased flammability, provide enhanced mechanical characteristics, decreased moisture uptake, and increased hygrothermal durability when used at particle loading levels comparable to those of conventional fillers, suggesting that these novel systems could be considered for critical structural applications. [ABSTRACT FROM AUTHOR]

A new pore type, nano-scale organo-clay complex pore-fracture was first discovered based on argon ion polishing- field emission scanning electron microscopy, energy dispersive spectroscopy and three-dimensional reconstruction by focused ion-scanning electron in combination with analysis of TOC, Ro values, X-ray diffraction etc. in the Cretaceous Qingshankou Formation shale in the Songliao Basin, NE China. Such pore characteristics and evolution study show that: (1) Organo- clay complex pore-fractures are developed in the shale matrix and in the form of spongy and reticular aggregates. Different from circular or oval organic pores discovered in other shales, a single organo-clay complex pore is square, rectangular, rhombic or slaty, with the pore diameter generally less than 200 nm. (2) With thermal maturity increasing, the elements (C, Si, Al, O, Mg, Fe, etc.) in organo-clay complex change accordingly, showing that organic matter shrinkage due to hydrocarbon generation and clay mineral transformation both affect organo-clay complex pore-fracture formation. (3) At high thermal maturity, the Qingshankou Formation shale is dominated by nano-scale organo-clay complex pore-fractures with the percentage reaching more than 70% of total pore space. The spatial connectivity of organo-clay complex pore-fractures is significantly better than that of organic pores. It is suggested that organo-complex pore-fractures are the main pore space of laminar shale at high thermal maturity and are the main oil and gas accumulation space in the core area of continental shale oil. The discovery of nano-scale organo-clay complex pore-fractures changes the conventional view that inorganic pores are the main reservoir space and has scientific significance for the study of shale oil formation and accumulation laws. [ABSTRACT FROM AUTHOR]

Monolithic silica-based aerogels, produced with tetraethoxysilane (TEOS), reinforced with aramid fibers and incorporating aluminosilicates were prepared for the first time. The nanocomposites were obtained by varying the amount and type of aramid fibers and replacing a part of the synthetic Si (up to 35 wt% of Si) of TEOS by natural aluminosilicates, kaolin and palygorskite. The effects of the type and amount of both fiber and mineral in the materials key properties were investigated. Most samples displayed very low volumetric shrinkages during ambient drying (<5%), high porosity (∼90%), and low bulk densities, down to 120 kg m−3. Composites with both minerals exhibited superinsulating thermal performance, with thermal conductivity reaching values as low as 22 mW m−1 K−1, while also showing excellent thermal stability. The mechanical properties of the designed clay mineral-silica aerogels can be tailored, since the addition of short length fibers (Kevlar pulp) produces stiffer composites, while the longer fibers (Teijinconex) lead to more flexible ones. [ABSTRACT FROM AUTHOR]

Polymer nanocomposites, such as polyethylene terephthalate (PET)-clay systems, leverage intricate interactions between components to fine-tune their thermal, mechanical, and rheological properties. In our study, we functionalized montmorillonite clay nanofillers (CloisiteNa+) to fabricate recycled PETclay nanocomposites. The nanofillers underwent a three-step functionalization process, involving the treatment with (3-Aminopropyl)triethoxysilane (APTES), the grafting of initiating coatings (multifunctional peroxide initiator, [MPI]) onto clay/APTES, and the subsequent fabrication of grafted brushes using poly(butyl methacrylate) (PBMA) or poly(butyl acrylate) (PBA). The functionalization process and the properties of the modified clay were successfully confirmed through Fourier-transform infrared spectroscopy and thermogravimetric analysis. The fabrication of nanocomposites, incorporating both clay and functionalized clay, influenced the thermal behavior of the composites, whereas the nanofillers had no discernible impact on the flow temperature. The PET and nanocomposites exhibited liquid viscoelastic behavior, with the exception of PET with clay, which displayed shear-thinning and “rubberlike” behavior. Rheological curves and x-ray diffraction (XRD) analysis indicated improved dispersion and compatibility for clay/APTES and clay functionalized with PBA-grafted brushes within the PET matrix. In some instances, the utilization of functionalized clay resulted in enhanced compatibility and customized properties in PET-organoclay nanocomposites compared with conventional fillers. These findings bear implications for a broad spectrum of applications involving PET-organoclay nanocomposites. [ABSTRACT FROM AUTHOR]

This document discusses a research paper that proposes a modified method for evaluating the stability of deep excavations in soft clays. The discussion raises concerns about the proposed method and questions the assumptions made by the authors. It suggests alternative explanations for the observed behavior of excavations in soft clays and criticizes the models used in the study for not accurately representing actual ground movement patterns caused by excavation. The author invites the study authors to respond to these criticisms. [Extracted from the article]

In this approach, nanocomposites of PVDF/PMMA/CTAMag films have been successfully synthesized. Modified Maghnite was used as inorganic reinforcement. In this study, nanocomposite polymers were developed based on a mixed matrix of poly(vinylidene fluoride) (PVDF) and poly(methyl methacrylate) (PMMA) of composition (80/20 w/w) in dispersion containing 0, 1, 3, 5 and 7 wt % fillers of organomodified montmorillonite nanoclay (CTAMag) in the melt state. The results obtained by scanning electron microscopy (SEM), XRD traces and FTIR spectra highlighted the homogeneous flexible character of the PVDF/PMMA/CTAMag films and their intercalated and intercalated/exfoliated surface morphology, in addition to the presence of PVDF α, β and γ phase crystallites in these complex films. The increased presence of the modified clay in the host matrix of the PVDF/PMMA blend significantly influenced the melting temperature and the degree of crystallinity of the PVDF crystallites. The scattering of the dielectric spectra, which covers a wide range of frequencies from 20 Hz to 1 GHz, indicates the presence of the phenomenon of interfacial polarization associated with the dielectric capacitance complex at lower frequencies in these composites at 27 °C. The mechanical properties of these composites were evaluated as a function of the load and the mixed matrix of these composites. [ABSTRACT FROM AUTHOR]

Polymer-based composites modified with organoclay are economically beneficial candidates for a variety of applications. Different types of impurities accompany montmorillonite phases in various bentonites, which impact the quality and cost of organoclays and final composites. To obtain organoclays for clay composite applications, eight Iranian raw bentonites from different geographical locations were selected as the candidates and characterized by X-ray diffraction (XRD). Sample IB was chosen due to its high purity and lower cristobalite content than the other samples. It was purified by centrifugation or sedimentation methods using a sodium hexametaphosphate (NaHMP) dispersant. The cation-exchange capacity (CEC) was measured for bentonite before and after purification by sedimentation, and it showed a significant increase from 6.944 to 12.128 eq g –1 , confirming successful purification. Organoclays were prepared using purified bentonite (sedimentation method) with two surfactants (cetyltrimethylammonium bromide and octadecylamine), and the amount of octadecylamine was optimized. Purified bentonite and organoclay were characterized by XRD, scanning electron microscopy (SEM) and X-ray fluorescence. The results indicate that most of the impurities were removed after purification, and the interlayer space of organoclays increased to 35 Å in the optimized sample prepared with an amount of octadecylamine that was twice the CEC in purified bentonite. The prepared organoclay was used to improve low-density polyethylene (LDPE) polymer properties. The clay–polymer composite properties were studied by field emission SEM, thermogravimetric analysis and tensile strength tests. The organoclay was fully dispersed in the LDPE matrix and in the sample with 5 wt.% of organoclay, where T i (the temperature at which 10% of the sample is decomposed) and T 50% (the midpoint of degradation) were 17°C and 13°C greater than those of polyethylene, respectively. Additionally, the sample residue with 5 wt.% of organoclay at 600°C was 43.4%. The tensile strength of polyethylene increased from 8.67 to 9.03 MPa in the sample with 4 wt.% of organoclay. [ABSTRACT FROM AUTHOR]

The aim of this work was to synthesize and study the functional properties of polymer-clay nanocomposite (PCNCs) based on poly(sodium 4-styrene sulfonate) (NaPSS) and two types of clay in the dispersed phase: bentonite and kaolinite, in order to advance in the development of new geomimetic materials for agricultural and environmental applications. In this study, the effect of adding high concentrations of clay (10–20 wt. %) on the structural and functional properties of a polymer–clay nanocomposite was evaluated. The characterization by infrared spectroscopy made it possible to show that the PCNCs had a hybrid nature structure through the identification of typical vibration bands of the clay matrix and NaPSS. In addition, scanning electron microscopy allowed us to verify its hybrid composition and an amorphous particle-like morphology. The thermal characterization showed degradation temperatures higher than ~300 °C with Tg values higher than 100 °C and variables depending on the clay contents. In addition, the PCNCs showed a high water-retention capacity (>2900%) and cation exchange capacity (>112 meq/100 g). Finally, the results demonstrated the ability of geomimetic conditioners to mimic the structure and functional properties of soils, suggesting their potential application in improving soil quality for plant growth. [ABSTRACT FROM AUTHOR]

The addition of nano clay composite and reactive diluents was found to be good for various properties of the composite when individually used. This research aims at the preparation of modified nanocomposites and investigating their mechanical properties. Mechanical testing, crosslinking density, surface morphology, and functional groups present in the composite were observed in this research. The composites were mixed with varying wt.% (2, 5, 7, 10) of 2-(2-hydroxypropoxy) propan-1-ol reactive diluent and a steady (5 wt.%) of nano clay mixed in epoxy. Mechanical testing samples were manufactured in line with ASTM standards. Scanning Electron Microscope and Fourier Transformation Infrared Spectroscopy tests have been conducted to investigate the surface morphology and the presence of functional groups present in the system. The swelling behaviour of the samples has been observed to gain a better understanding of crosslinking density. The tensile and fracture toughness behaviour of the composite was greatly improved. In addition, 7 wt.% diluent and 5 wt.% nano clay in the pristine epoxy reveal an optimal property. Including nano clay and reactive diluent 2-(2-hydroxypropoxy) propan-1-ol in differing amounts improves tensile and fracture resilience by (19–23)%, suggesting a tight forming bond between epoxy, nano clay, and diluent. [ABSTRACT FROM AUTHOR]

Thermal degradation of poly(butylene terephthalate) (PBT)/organically modified clay (organoclay) nanocomposites at elevated extrusion temperatures is inevitable and restricts the extensive use for these nanocomposites. This study aimed to prepare PBT/organoclay nanocomposite with enhanced properties by chain extender assisted reactive extrusion approach. A commercial organoclay, Cloisite 30B (C30B), was employed to prepare nanocomposite and a chain extender having multi epoxy functional groups, Joncryl ADR 4300 (Joncryl), was used to compensate thermal degradation of PBT accelerated by the organoclay for the first time. The morphological observations revealed high delamination of C30B within the matrix and the incorporation of Joncryl led to a well-exfoliated structure. The non-chain extended nanocomposite showed the matrix degradation in the rheological tests, where the notable benefit of the chain extender to offset degradation was observed by improvements in the viscoelastic properties. Compared to neat PBT, the tensile modulus of non-chain extended nanocomposite increased by 33 %, whereas a 56 % enhancement was measured for nanocomposite with chain extender. Thermogravimetric analyses indicated higher thermal decomposition temperature with addition of Joncryl into the nanocomposites. It was concluded that Joncryl recoupled degraded chains of PBT and effectively improved the features of nanocomposites.

The synergistic effect of organoclay (OC) and zinc oxide (ZnO) nanoparticles on the crucial properties of poly(lactic acid) (PLA) nanocomposite films was systematically investigated herein. After their incorporation into PLA via the solvent casting technique, the water vapor barrier property of the PLA/OC/ZnO film improved by a maximum of 86% compared to the neat PLA film without the deterioration of Young's modulus or the tensile strength. Moreover, the film's self-antibacterial activity against foodborne pathogens, including gram-negative (Escherichia coli , E. coli) and gram-positive (Staphylococcus aureus , S. aureus) bacteria, was enhanced by a maximum of approximately 98–99% compared to the neat PLA film. Furthermore, SEM images revealed the homogeneous dispersion of both nano-fillers in the PLA matrix. However, the thermal stability of the film decreased slightly after the addition of the OC and ZnO. The film exhibited notable light barrier properties in the UV-Vis range. Moreover, the incorporation of a suitable biodegradable plasticizer significantly decreased the T and notably enhanced the flexibility of the nanocomposite film by increasing the elongation at break approximately 1.5-fold compared to that of the neat PLA film. This contributes to its feasibility as an active food packaging material. Graphic Abstract [ABSTRACT FROM AUTHOR]

The influence of surface modification and some processing parameters on the palygorskite (Pal) dispersion and the mechanical, thermal and rheological properties of the resulting Nylon 6 nanocomposites was investigated. Natural Pal was surface modified with hexadecyl tributyl phosphonium and 3‐aminopropyl trimethoxysilane to produce organoclays with different surface energy values. Nylon 6/Pal nanocomposites were produced by twin screw extrusion and then injection molded, Pal loading was 2 wt. % in all the cases. A screw configuration was designed to impose different level of shear stresses to the nanocomposites during processing, and nanocomposites were extruded at two different screw speeds. Scanning electron microscopy (SEM) and transmission electron microscopy (TEM) observations indicated that Pal was dispersed differently depending mainly on the degree of shear stress and surface modification of Pal. The best tensile mechanical properties were achieved with Pal exhibiting the lowest surface energy value dispersed with the screw having high shear configuration. The fatigue life of nylon 6 improved with addition of Pal. The experimental results give some guidelines for producing Nylon 6/Pal nanocomposites with improved properties. [ABSTRACT FROM AUTHOR]

In this study, montmorillonite clay (MT) was modified for the first time with CuFe2O4 spinel ferrite nanoparticles and assessed as a recyclable catalyst for the one-pot synthesis of 1,3-thiazolidin-4-ones under solvent-free microwave irradiation conditions with a high to excellent yield. The morphology and chemistry of the CuFe2O4@MT (CuF@MT) nanocomposite were characterized using X-ray diffraction (XRD) patterns, field-emission scanning electron microscopy (FE-SEM) images, transmission electron microscope images, and vibrating sample magnetometer curve analyses. The results indicated the presence of CuFe2O4 with a tetragonal structure, a consistent distribution, and no aggregation at MT. The findings further indicated that CuF@MT's superior magnetic characteristics led to its use as a heterogeneous catalyst in manufacturing 1,3-thiazolidin-4-one derivatives. This technique offers various advantages, including mild reaction conditions, high efficiency, and fast recovery of the nanocatalyst. [ABSTRACT FROM AUTHOR]

In recent years, clay-based organic thermosetting polyurethane polymer nanocomposites have more attracted attention in academia and industries because they exhibit different properties from conventional materials. In this study, we investigated novel thermoplastic Polyurethane (TPU) by adding nanoparticles of clay as a fire-retardant property. By employing an in-situ polymerization technique with a 2:1 ratio of tolylene 2,4-diisocyanate (TPI) and polyethylene glycol (PEG2000), the NCO terminated TPU prepolymer was created. Cloisite 25A (C25A), an organo-modified montmorillonite clay, was utilized to provide sufficient compatibility with the PEG/TPI matrix. The synthesized nanocomposite was examined using thermogravimetric analysis (TGA), SEM analysis, and X-ray diffraction (XRD). FTIR analysis provides information on functional groups. Compared to pure polyurethane, the nanocomposites showed superior thermal stabilities, as determined by thermogravimetric analysis (TGA). The results from X-ray diffraction and Scanning Electron Microscopy confirm the successful formation of an exfoliated polymer clay nanocomposite under all conditions, evidenced by the absence of the distinct peak (2θ = 4.79°) corresponding to the d-spacing of the organoclay. The relationship between clay loading and TPU matrix type and the mechanical characteristics of nanocomposites was examined. As the amount of clay in the Young's TPU/Cl25A nanocomposites grew, so did their tensile strength and modulus. The fire-retardant experiment was studied by a cone colorimeter. There have been notable advancements in the fire-retardant qualities, including smoke, CO output, and heat release rate. Comparing polyurethane integrated with 5-weight percent organoclay to ordinary polyurethane polymer, a noteworthy 53% reduction was observed. [ABSTRACT FROM AUTHOR]

This research focuses on the preparation of poly (3-hydroxy butyrate) (PHB) nanocomposites using the melt mixing method. Two types of organically modified nanoclay, Cloisite 93A (C93A), and Cloisite 30B (C30B), were incorporated at various weight percentages into the PHB matrix to create the nanocomposites. Comparative analyses were conducted between PHB/C93A and PHB/C30B to assess their tensile and impact properties in relation to the matrix polymer. Between the nanocomposites, the PHB/C93A nanocomposites shows an optimum tensile modulus of 949 Mpa with a 3 wt% clay loading, while PHB/C30B nanocomposites demonstrated improved percentage elongation at break of 5.33 % and enhanced Izod impact strength of 39.67 J/m at 3 wt% of clay load. The thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC) signifies the thermal behavior of both the matrix and nanocomposite. The degree of crystallinity is observed to be 47 % in case of the PHB/C30B nanocomposites as compared to the PHB/C93A nanocomposites as 38 %. Again in case of thermogravimetric analysis (TGA), the maximum % char of 5.198 is observed for the PHB/C30B nanocomposites. The enhanced viscoelastic behavior of the PHB/C93A nanocomposites was attributed at a peak of approx. 55–60 °C due to the incorporation of C93A nanoclay into the matrix in the study of dynamic mechanical analysis (DMA). The morphological investigation using WAXD analysis showcased particle clay intercalation and dispersion within the PHB matrix, indicating effective clay-matrix interactions. Overall, this study sheds light on the enhanced properties of PHB nanocomposites with the incorporation of organoclay, offering potential applications in various industries. [ABSTRACT FROM AUTHOR]

With the widespread use of geopolymer, the effective activation and utilization of thermally activated termite soils as alternative or eco-friendly material are great of interest. The present study investigated the use of calcined termite soils (TC) in geopolymer pastes and mortars as a precursor, while metakaolin (MK) was used as a reference material to prepare control samples. The physicochemical properties of both raw and calcined solid precursors as well as geopolymer pastes and mortars were characterized using various techniques, including BET, PSD, XRF, XRD, setting time, ICC, and SEM/EDS. Results showed that termite soil can be successfully employed as a starting material in geopolymer production. Pastes and mortars prepared using TC gave significant compressive strengths of 43.2 and 33.2 MPa, respectively, although they were approximately 26% and 6% lower than control samples made using MK. Based on the analytical studies, better mechanical performance of MK-based binders compared to TC-based ones is attributed to the presence of reactive phases within MK that promotes the geopolymerization resulting in the development of a stronger geopolymer network and better connectivity within the matrix. It can be concluded that TC can be considered as a suitable raw material for the production of geopolymer binder considering the availability and accessibility in certain regions. [ABSTRACT FROM AUTHOR]

The Yoon–Nelson model serves as a widely used tool for describing the breakthrough behavior of organic micropollutants within fixed bed adsorbers. This study aims to augment its modeling efficacy through two proposed refinements found in the literature: a logarithmic transformation and the incorporation of steric hindrance effects. We systematically evaluated the original Yoon–Nelson model alongside the modified versions, using breakthrough data associated with micropollutant adsorption on solid materials. Three distinct cases were scrutinized: (1) caffeine adsorption on activated carbon; (2) tetracycline adsorption on hierarchical porous carbon; and (3) diclofenac adsorption on organoclay. While all three models demonstrated comparable performance with highly symmetric breakthrough data in case 1, their efficacy diverged significantly when confronted with strongly asymmetric breakthrough data in cases 2 and 3. The original Yoon–Nelson model and the logarithmically modified version fell short in accurately representing these intricate breakthrough curves. In contrast, the version incorporating steric hindrance effects showcased substantial accuracy, outperforming other models in capturing the complexities of asymmetric breakthrough data. This advancement markedly enhances the modeling accuracy and versatility of the Yoon–Nelson model, particularly in assessing the dynamic behavior of organic micropollutants within fixed bed adsorbers. [ABSTRACT FROM AUTHOR]

In this paper, the abrasion resistance of a carbon fiber composite based on epoxy nanocomposite matrix filled with layered-silicate clay nanoparticles was evaluated. In the first step of the work, the clay-epoxy nanocomposite was first studied to assess the dispersion and the performance, and then to select the best content for the fiber composite production. The nanocomposite mixture was prepared by finely dispersing clay nanoparticles into the epoxy monomer through mechanical stirring, then the hardener was added. After this step, the fiber reinforced composite was produced by vacuum infusion, and then the properties were evaluated. The abrasion resistance has been assessed using different approaches. A test was specifically designed to simulate the impact of abrasive powders which could potentially be found in the atmosphere and crash into aircraft or air vehicles (such as for instance volcanic ashes). The results showed that the presence of nanoclay reduces the weight loss of the sample with the impacted surface, which can be clearly correlated to a damage reduction. Highlights • Sandblasting tool made to mimic impact of abrasive powder on composite surface • Presence of nanoclay does not significantly affect the vacuum infusion process • Layered-silicate nanoparticles lead to improve composites abrasion resistance. [ABSTRACT FROM AUTHOR]

Mesoporous silica nanoparticles were synthesized by base-catalyzed hydrolysis of tetraethyl orthosilicate in the water-acetone medium. For surface modification of mesoporous silica, commercially available silane, 3-(trimethoxysilyl)propyl methacrylate was reacted with mono-thioglycerol via 2,2,6,6-tetramethylpiperidin-1-yl)oxidanyl (TEMPO) aided thiol-ene reaction, and the obtained silane was incorporated on the surface of neat mesoporous silica to graft extended alkyl chains terminating in hydroxyl groups. The prepared MSNs were characterized by thermal gravimetric analysis (TGA), Fourier transform infrared spectroscopy (FT-IR), nitrogen adsorption-desorption analysis, scanning electron microscopy, and dynamic light scattering. These MSNs were compared to conventionally used commercial silica as an additive in tubular quenched polypropylene films (TQPP) for their anti-blocking, thermal, mechanical, optical, and barrier properties. Organic modification of MSNs decreased the blocking force in TQPP films. The mechanical properties including % elongation and tensile strength increased for TQPP films with mesoporous silica, while it decreased for films containing commercial silica. Both modified and unmodified MSNs decreased haze and enhanced gloss in TQPP films, showing improved optical properties as compared to commercial silica particles. In TQPP film with modified MSNs, a reduced value of the water contact angle was obtained, indicating better wettability of the surface of the TQPP film. [ABSTRACT FROM AUTHOR]

Polybutylene terephthalate (PBT) nanocomposites loaded with two different types of organoclays are fabricated using the melt mixing technique in a twin-screw extruder. Quaternary ammonium salts with dimethyl, benzyl, hydrogenated tallow, and dimethyl, dehydrogenated tailed modified organoclays are blended with PBT matrix at the compositions of 1%, 3%, 5%, and 10% weight ratios. Test samples are shaped using a lab-scale injection molding device. Mechanical, thermo-mechanical, thermal stability, melt flow, structural, and morphological behaviors of the nanocomposite samples are investigated by performing tensile, impact, and shore hardness tests, dynamic mechanical analysis (DMA), thermo-gravimetric analysis (TGA), melt flow rate measurements, X-ray diffraction analysis (XRD), and scanning electron microscopy (SEM) methods, respectively. According to the findings, NC 130 clay gave better results than NC 140 in terms of tensile, hardness, and melt flow behaviors, whereas NC 140 showed higher performances as impact resistance, thermo-mechanical, and density, since the reduction in density and weight lowering are highly required for mainly transportation sector, and thermal properties were considered. [ABSTRACT FROM AUTHOR]

This paper presents a groundbreaking study on the synergistic effect of combining Cloisite 30B (C30B) organoclay with styrene-butadiene-grafted glycidyl methacrylate (SbB-g-GMA), a dual-functional impact modifier and compatibilizer with the ultimate aim of developing high-performance materials based on polyethylene terephthalate (PET), and polystyrene (PS) with superior thermal and mechanical properties, thereby exploring the feasibility of recycling of these commonly used plastics via a simple melt blending approach. The morphology of the melt-mixed PET/PS blends and dispersion state of organoclay in the PET/PS/C30B nanocomposites in the presence and absence of the compatibilizer were analyzed by the X-ray diffraction, field emission scanning electron microscopy (FE-SEM), atomic force microscopy (AFM), and transmission electron microscopy (TEM). Furthermore, the thermal and mechanical properties of the nanocomposites were evaluated through TGA/DSC analysis and tensile and Izod impact tests. The microscopic images revealed that the addition of the SbB-g-GMA compatibilizer resulted in a superior dispersion of the nanoclay platelets. The composition of 70% PET, 30% PS, 7 phr SbB-g-GMA, and 3 phr C30B yielded the best dispersion of C30B and the most favorable thermomechanical properties in the PET/PS/SbB-g-GMA/C30B blend. Interestingly, the study found that using the nanoclay alone was insufficient to achieve compatibility between PET and PS. Optimal results were obtained when SbB-g-GMA was mixed into the PET/PS/C30B nanocomposite. The mechanical properties, including tensile and impact strength, modulus, elongation at break, as well as the thermal stability, exhibited significant improvements upon the addition of the synthesized SbB-g-GMA dual-functional compatibilizer compared to both the binary blends of PET/PS and the PET/PS/C30B nanocomposite. [ABSTRACT FROM AUTHOR]

The antibacterial, antifungal and antioxidant effects of halloysite nanoclay, Cloisite 10A (C10A) and Cloisite 15A (C15A) organonanoclays were examined in this study. The antimicrobial action was assessed using the agar-well method and the disc diffusion method. The free radical-scavenging effects of the clays were determined using the 2,2-diphenyl-1-picrylhydrazyl method. Halloysite showed antimicrobial activity against Pseudomonas aeruginosa , Enterococcus faecalis and Staphylococcus aureus. C10A was effective against both Gram-positive bacteria (S. aureus , Listeria monocytogenes , Bacillus subtilis and E. faecalis) and Gram-negative bacteria (Escherichia coli , Klebsiella pneumoniae and P. aeruginosa). Additionally, only C10A was found to have an antimicrobial effect on Candida glabrata of 18 mm amongst the tested clays. C15A showed an antimicrobial effect on S. aureus and K. pneumoniae. It was determined that the antifungal properties of organoclays were higher than those of halloysite. The most effective clay type was determined to be C10A. The positively charged inner surface of the halloysite nanoclay can provide a large area to which negatively charged free radicals can attach. The modified C15A used in this study has two long-chain alkyl groups attached, whereas the modified C10A has a single long-chain alkyl group and a benzyl group attached. It is proposed that the differences in these antimicrobial effects are due to the structures of the molecules. According to these results, organoclays as green source materials could be used as additives and coatings in food processing, biomedical devices, filters and paints due to their antimicrobial and antioxidant properties. [ABSTRACT FROM AUTHOR]

Elastomeric 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. [ABSTRACT FROM AUTHOR]

Native cassava starch was modified by dry heating treatment, and sodic montmorillonite was modified using an alkylpolyglucoside biosurfactant to produce a novel montmorillonite‐filled starch bionanocomposites with improved performance. The bionanocomposites were produced in two extrusion steps using a co‐rotating twin‐screw extruder. The structural properties of the bionanocomposites were studied by X‐ray diffraction. The reinforcement effect and material performance were evaluated by hydrophobicity, solubility, opacity, barrier, thermal and mechanical properties. In general, the dispersion of the nanofillers resulted in bionanocomposites with intercalated structures and improved properties compared with unfilled bioplastics. The main results exhibited that modified montmorillonite showed better compatibility with starch, improving nanofiller dispersion and interaction than the native one. As a result, it increased the hydrophobicity and reduced solubility, water, and oxygen permeabilities in comparison with bionanocomposites based on native starch by 36%, 48%, and 68%, respectively. Also, the tensile strength and Young modulus increased from 0.60 to 2.56 MPa and from 2.99 to 15.68 MPa, respectively. In conclusion, modification of MMT by the biosurfactant is a good approach to enhance dispersion/interaction with the starch matrix. [ABSTRACT FROM AUTHOR]

This study involved the preparation of composites consisting of zinc oxide (ZnO) nanoparticles deposited within the structure of organophilic bentonite. These composites were subsequently utilized as fillers in natural rubber (NR). The organobentonites were initially prepared via a cation exchange reaction using alkylammonium ions with different chain lengths (C8N−C18N) and later deposited by ZnO nanoparticles. The identification of the ZnO‐organobentonites was conducted using various techniques, including powder X‐ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), UV‐Vis spectroscopy, etc. The findings demonstrate the successful deposition of ZnO nanoparticles within the organobentonite's structure. The basal space between the silicate layers increased with the increasing chain length of alkylammonium ions. When added to NR, the ZnO‐organoclays mutually acted as a cure activator and filler. As expected, the ZnO‐organoclay modified by octadecylammonium ions (C18N) showed the greatest reinforcement due to its highest capability to enlarge the basal space between the silicate layers. [ABSTRACT FROM AUTHOR]

The design and development of environmentally oriented cements with predominant content of widespread noncalcined precursors contribute to a more promising future for constantly evolving alkali-activated materials (AAMs). In this study, natural and designed blends of calcined clays and abundant raw calcium carbonate minerals were investigated as binary precursors for one-part AAMs using standard techniques, thermal, X-ray diffraction, and scanning electron microscopy/energy dispersive spectroscopy (EDS) analyses. The influencing factors to set optimal parameters were the mineralogical assemblage, precursors fineness, formulation details, means of alkali reactant incorporation, and curing regimes. It was stated that hydraulic one-part AAMs can be derived from calcined marl incorporated with limestone powder containing 5.8%–7.0% of calcined clay minerals and 54.6%–60.5% of calcite or nonhydraulic one-part AAMs from a mixture consisting of 20%–30% metakaolin and 70%–80% limestone powder. It was found that, compared with a metakaolin-limestone-based binary precursor, alkali activation of calcined marl–limestone results in the formation of a higher amount of binder gel with a greater extent of Ca incorporation into the structure of Na aluminosilicate gel and the formation of Ca aluminosilicate and Ca silicate hydrogels. This provides an alkali-activated calcined marl–limestone binder system with better mechanical properties and continuous strength development, including under wet conditions. [ABSTRACT FROM AUTHOR]

Responsive polymers can be combined with clay particles to form adaptable, or "tunable," clay–polymer composites. The purpose of this study is to investigate the potential for "tunability" of a nanocomposite at the mesoscale through changes in material properties—swelling behavior, Atterberg limits, hydraulic conductivity, and shear strength—with varying pH and ionic concentration of the surrounding fluid. The composite was synthesized from a nonionic form of the polymer polyacrylamide and an expansive clay, montmorillonite. An attempt was made to induce changes in behavior of the composite by exposing the material to a selected range of pH and ionic concentration conditions, thereby influencing the conformation (shape and size) of the responsive polymer molecules under different stress levels and solid contents. Behavior was compared for the cases of predicted coiled, partially extended, and extended conformation. The test results demonstrate that conformation of responsive polymer and tunability of composite depends primarily on solution type, stress levels, and solid content. The "tuning" response of a nanocomposite is maximized with a significant change in ionic concentration of the surrounding fluid. Nanocomposite swelling was 30% less than pure clay and had a friction angle 12° greater than pure clay at high ionic concentration. At low or high pH conditions, nanocomposite tunability was limited. [ABSTRACT FROM AUTHOR]

Triple shape memory materials currently have a wide range of applications in aerospace and healthcare. In this study, Organic clay (OC) was introduced as a reinforcing phase in trans-isoprene (TPI) and low-density polyethylene (LDPE) matrix. TPI/LDPE/OC shape memory composites (SMP) were prepared by melt blending and vulcanized and pressed using dynamic vulcanization technique. In order to reveal the effect of OC content on the mechanical and shape memory properties of TPI/LDPE/OC composites, a series of experiments were conducted. The results show that the optimum vulcanization time of the composites decreases linearly with increasing OC content. The torque difference of the composites is maximized when OC is added at 2 phr, which indicates that the cross-linking degree of the composites is optimal at this time; In addition, with the increase of OC content, the mechanical properties, crystallization properties and shape memory properties of the composites first increase and then decrease. This is due to the fact that OC can form a stable and homogeneous interlayer structure with the composite matrix in the appropriate amount, which will play a role in enhancing the properties, but when OC is added in excess, agglomeration occurs within the composite matrix, thus reducing the properties; The crosslinking degree, tensile strength, crystallinity and triple shape memory properties of the composites were optimized when the OC content was 2 phr. This study provides potential value for research on the application of multiple shape memory materials. [ABSTRACT FROM AUTHOR]

A new type of geopolymer with an iron–oxygen–silicon linkage is synthesized and reported for the first time. The aim was to enable the iron-rich clay material (laterite) as a raw material for the geopolymerization. Iron was used in different ratios ranging 1–3 wt. % in the raw mix designing geopolymer followed by activation with concentrated alkali solutions of NaOH and KOH in different concentrations. The bonding of Fe–O–Si was confirmed from the FTIR peaks in NaOH- and KOH-based geopolymers. X-ray diffraction studies confirmed the formation of zeolitic, sodalite, and almandite phases. The final product has shown a compressive strength of 2371.8 and 1503 kN/m2 and can be used as a construction material. [ABSTRACT FROM AUTHOR]

The blends of poly(D-lactic acid) and poly(L-lactic acid) (PDLA/PLLA) produce the stereocomplex crystals (SC) with a melting temperature of ~ 250 °C, which exhibits higher crystallization rate and mechanical strength than PDLA or PLLA. The SC was also reported as an effective nucleator for PLA homochiral crystals (HC). In the PDLA/PLLA blends, the SC would develop at first in most of cases. However, the morphology of SC in the asymmetric blends were rarely reported, and the effect of the SC morphology on the subsequently crystallization of HC was not clear yet. In this study, the PDLA/PLLA blends with dissimilar weight ratios were prepared by three methods, i.e., electrostatic spinning, solution casting, and melted-cooling, and the SC with different morphologies were achieved. Then, the crystallization behavior of HC under the existence of SC was studied. Results indicated that the SC morphology exerted diverse effects on the formation of HC. The SC with fibrous and banded morphology produced by electrostatic spinning presented great limitation for the formation of HC. The SC with spherical morphology developed in the solution casting films enhanced the formation of HC. The SC with network structure produced in the melted-cooling specimens accelerated the crystallization rate of HC significantly. This investigation indicated that not only the content of SC, but also the morphology of SC would influence the crystallization behavior of HC, which would make a deep understanding for the crystallization behavior of PDLA/PLLA specimens. [ABSTRACT FROM AUTHOR]

Polymer clay nanocomposites, which can exhibit many superior properties compared to virgin polymers, have gained increasing interest and importance in recent years. This study aimed to prepare composites of two organoclays with unusual ratios and different degrees of lyophilicity with low-density polyethylene and compare their textural structures and thermal and mechanical properties with those of virgin polymer. For this purpose, firstly, organoclays, hydrophobic and superhydrophobic organoclays (OC and SOC), were prepared by solution intercalation method using cetyltrimethylammonium bromide with and without addition of a hydrocarbon substance. Then, using both organoclays, polyethylene organoclay composites were prepared and characterized using X-ray powder diffraction (XRD), high-resolution transmission electron microscopy (HRTEM) and Fourier transform infrared spectroscopy (FTIR) techniques. Additionally, tensile and hardness tests were performed to determine the mechanical properties of the composites, and differential scanning calorimetry (DSC) thermograms were taken to examine their thermal behavior. XRD patterns and HRTEM images of hydrophobic and superhydrophobic organoclays and the composites show that the characteristic smectite peak of the clay shifts to the left and expands, that is, the interlayer space widens and, in the composites, it deforms immediately at low clay ratios. HRTEM images of the composites prepared especially with low clay ratios indicate that a heterogeneous dispersion of clay platelets occurs, indicating that nanocomposite formation has been achieved. On the contrary, in the composites prepared with high clay ratios, this dispersion behavior partially turns into aggregation. In the composites prepared using up to 20% by weight of superhydrophobic organoclay, extremely stable and continuous improvements in all mechanical properties were observed compared to those of the composites prepared using hydrophobic organoclay. This indicates that by using superhydrophobic organoclay, a ductile nanocomposite of polyethylene containing inorganic components in much higher than usual proportions can be prepared. [ABSTRACT FROM AUTHOR]