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The problem of goaf treatment has become more and more prominent, posing a significant risk to the safety of transportation and causing environmental damage if it is not treated properly. This study aims to conduct a comparative analysis of various grouting pastes and evaluate their application in goaf treatment according to grouting backfilling. This research begins by discussing different grouting pastes' properties, including clay-cement composite grouting material and geopolymer grouting material, which have excellent engineering performance, environmental friendliness, and are easy to operate in complex geological environments. Moreover, the factors affecting the performance of grouting pastes, such as water-solid ratio and curing time, are also examined. Based on detailed information about the boreholes provided by drilling television, a reasonable treatment plan is formulated for goaf treatment. Finally, this study evaluates the effectiveness of different grouting pastes in real-world goaf treatment projects. The study draws the following conclusions: a direct relationship exists among flowability, setting time as well as water-solid ratio. An inverse relationship exists between the compressive strength of grouting materials and the water-solid ratio. Drilling data reveals complex goaf structures with defects such as water leakage, collapse and cavity, indicating potential geological risks in shallow areas. A treatment plan is formulated based on the geological conditions of goafs by drilling television. The effectiveness of backfill grouting in goaf areas is inspected using ground-penetrating radar (GPR) technology, and results indicate that adjusting water-solid ratio of grouting material can improve treatment effects. [ABSTRACT FROM AUTHOR]

In this study, the removal of methylene blue (MB) by both raw and modified clay as an abundant, cost-effective was investigated. The modification of the raw clay was done by calcination, acid treatment, and again second calcination processes. In addition, the effects of calcination temperature and acid/base concentration on the adsorption capacity of clay were investigated. The characterisation of clay was performed by scanning electron microscopy (SEM) and Fourier transformed infrared spectroscopy (FTIR) analyzes. Langmuir and Freundlich isotherm models were used. The modified clay provided significant improvements in adsorption capacity compared to the raw clay. [ABSTRACT FROM AUTHOR]

The properties of nanocomposites are directly affected by the filler–matrix interaction and therefore surface filler modification is often necessary to improve the mechanical properties of nanocomposites. Our study evaluated surface modification of sepiolite (SEP) on properties of poly(butylene adipate‐co‐terephthalate) (PBAT)‐based nanocomposites. The nanofillers were modified using two organic modifiers, octadecyl isocyanate (OI), and 3‐aminopropyltriethoxysilane (APTES). OI showed higher treatment efficiency than APTES and better results in alkyl groups on the surface of the nanofiller, with crystalline profile, which remained in the nanocomposites. The effect of organo‐sepiolites on the properties of PBAT nanocomposites was investigated by DSC, XRD, TGA, FTIR, scanning electron microscopy (SEM), and mechanical tensile tests. TGA analysis showed that the addition of O‐SEP on PBAT decreases its thermal stability. SEM analysis showed cavities and fiber tips in the matrix associated with clay agglomerates and some untreated clay faces, which impair filler‐matrix interfacial adhesion. Both treatments increased the elastic modulus and preserved the elongation and tensile strength of PBAT and the treatment with OI results in a higher modulus. Although some studies to improve the clay dispersion are necessary, the promising results reveal the potential of using OI and APTES as SEP modifiers to reinforce PBAT or other polyesters. [ABSTRACT FROM AUTHOR]

Metal–organic frameworks (MOFs) is now becoming the most fascinating conductive materials due to designable structure and pores at molecular level, and available crystal structure for the study of conduction mechanism. Nevertheless, comparing to the design of molecular structures of MOFs, the hybrid of MOFs with special micro/nano‐structured materials is considered to be a more effective approach for improved properties. In this study, the PAT@UiO‐66‐SO3H hybrid material was constructed with high conductive UiO‐66‐SO3H, a famous kind of MOFs, and polydopamine‐coated natural clay attapulgite (PAT), then the prepared hybrid material was blended with chitosan (CS) to prepare proton exchange membranes (PEMs). Owing to the special architectures and microenvironment, combining with the advantages of composition with UiO‐66‐SO3H and attapulgite, the prepared composite membranes showed considerable improved performances, including tensile strength, thermal and structural stability, fuel resistance ability, conduction and single cell performances. The CS/PAT@UiO‐66‐SO3H‐5 composite membrane exhibited the highly enhanced tensile strength of 67 MPa and improved thermal stability with Tg value of 235°C, as well as the lowest methanol crossover value of 1.2 × 10−6 cm2 s−1. Besides, the highest proton conductivity of 38.8 mS cm−1 at 80°C and power density of 37.9 mWcm−2 was achieved with CS/PAT@UiO‐66‐SO3H‐3 composite membrane, these performances were higher than pristine CS of 22.7 mS cm−1 and 32.2 mW cm−2 respectively. Our investigation reveals great application potential of MOFs based hybrid materials in fabricating of high performance composite PEMs. Highlights: PAT@UiO‐66‐SO3H hybrid materials were constructed from MOFs and natural clay.The hybrid materials possessed special architectures and microenvironment.The PAT@UiO‐66‐SO3H introduced consecutive channels and proton sites.The hybrid membranes achieved excellent performances. [ABSTRACT FROM AUTHOR]

Anthropogenic toxic pollutants are ubiquitous and need to be removed from the environment. This study investigates the preparation of an inorganic‐organic modified clay (organo‐pillared‐clay) for the removal of contaminants. The present work investigates the compositional, structural and sorption properties of modified clay materials for the removal of perfluoroheptanoic acid (PFHpA). The chemical compositions of the clay materials used were determined by interlayer and surface analysis. The results showed changes in interlayer spacing and external surface area due to modification and surfactant addition during the cation exchange reaction. The combination of adsorption and irradiation increased removal efficiency, although photodegradation was partially inhibited. Modified clays show promise for PFHpA remediation, with potential for optimizing photodegradation processes. [ABSTRACT FROM AUTHOR]

A high content of metakaolin in calcined clay blended cement has a positive effect on the early strength development, however, it also leads to a poor workability. Moreover, slump retention is more difficult to achieve in this system than in OPC or other composite cements. In this study, several approaches were investigated to achieve fluidizing ability of mortars prepared from composite cements holding 30 wt. % of calcined clay with varying amounts of metakaolin (∼ 23 wt.%, ∼ 51 wt.%). First, it was found that the slump retaining performance of a common industrial ready‐mix type HPEG PCE rapidly decreases when the content of metakaolin increases. Furthermore, a combination of the ready‐mix HPEG PCE and a retarder (sodium gluconate) which is commonly applied in ready‐mix concrete, also fails to improve fluidity retention in calcined clay blended cement with a high level of metakaolin, hence highlighting the difficulty of slump retention for such cements. To mitigate this problem, a unique admixture based on the combination of a precast type HPEG PCE and a novel PCE‐LDH nanocomposite is introduced. Mortar tests reveal that the high water‐reducing (precast) type HPEG PCE and the PCE‐LDH nanocomposite enables to achieve a remarkable improvement in fluidity retention of such calcined clay blended cements. [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.

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.

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 This study aimed to create CTAB-modified bentonite organoclay (Bt@CTAB) by mixing the naturally occurring mineral bentonite (Bt) with the cationic surfactant cetyltrimethylammonium bromide (CTAB). Elemental analysis, N2 adsorption–desorption isotherm, scanning electron microscopy (SEM), FTIR spectroscopy, XRD, and thermogravimetric (TGA) analysis have been employed to analyze both the unmodified Bt and the Bt@CTAB organoclay. The dye sorption onto Bt@CTAB organoclay was investigated in the batch and column modes using aqueous solutions of anionic food dyes, viz., Sunset yellow FCF (E110), Azorubine (E122), and Ponceau 4R (E124) (individually or in a mixture). Experimental variables affecting the adsorption process, such as initial dye concentration, contact time, temperature, pH, and adsorbent dose, are evaluated. From the kinetic investigations, the adsorption of E110, E122, and E124 dyes well matched the pseudo-second-order kinetic model. E110 and E122 dyes adsorption onto Bt@CTAB attained equilibrium in 120 min while attained in 240 min for E124. The investigated food dyes were expected to achieve maximum adsorption efficiencies at concentration of 100 ppm of (E110 and E124) and 150 ppm of (E124), an adsorbent dosage of 0.4 gL−1, and an initial pH 5. In addition, Langmuir model best fits the sorption isotherm data, with the maximum adsorption capacity at 303 K being 238 mg/g, 248.75 mg/g, and 358.25 mg/g for E110, E122, and E124, respectively. The Bt@CTAB organoclay can be regenerated up to the 4th cycle successfully. The thermodynamic studies revealed the spontaneous and exothermic nature of the adsorption of these anionic dyes onto Bt@CTAB organoclay. The prepared cationic Bt@CTAB organoclay was successfully applied for the removal of E110, E122, and E124 from real water samples, synthetic effluents, and colored soft drinks with a recovery (R%) higher than 95%. The plausible adsorption mechanism of E110, E122, and E124 onto Bt@CTAB organoclay is proposed to be due to electrostatic interaction and hydrogen bond formation. Finally, the present study shows that Bt@CTAB organoclay may be employed efficiently and effectively to remove anionic food dyes from a wide range of real water and colored soft drinks.

Montmorillonite clay was modified by pillaring with AlMn oxides in different Al/Mn ratios and intercalation of two kinds of N-containing polymers (i.e., chitosan (CS) and polyvinyl pyrrolidinone (PVP)) chains. The modified pillared montmorillonite clay (PM) showed a rich two-dimensional layered porous structure with tunable parameters, such as large interlayer spacing, high specific area, and large porous volume. They were then used as supports for Pd nanoparticles. As applied in coupling reactions of aryl halides with terminal alkynes, Pd@CS/AlMn-PM showed better comprehensive catalytic performance than Pd@PVP/AlMn-PM. This was mainly attributed to its higher specific area, stronger chelation to Pd species, and better solvent resistance. [ABSTRACT FROM AUTHOR]

Thermal and flammability properties of ethylene vinyl acetate/starch/organoclay (EVA/S/C20A) nanocomposites are shown in this work. Wide-angle X-ray diffraction (WAXD) patterns and micrographs obtained by field emission scanning electron microscopy (FE-SEM) show the formation of nanostructured systems. The organoclay layers were preferably intercalated-exfoliated with the EVA polymer. Even so, the vinyl acetate group in EVA interacted with both the C20A clay and the starch macromolecules, achieving compatibility between the three components. The intercalated layers of clay provided protection against thermal degradation of the EVA. However, based on the kinetic study, the Ea of the nanocomposite degradation was lower than that of pure EVA. The flammability tests demonstrated the absence of dripping during burning and the self-extinguishing capacity of the flame (HB in the UL-94 test) in the EVA/C20A and EVA/S/C20A nanocomposites. The results are related to the nanointercalation of the clay and the compatibility between the three components with different properties. Thus, the flame self-extinguishing potential of ternary nanocomposites, previously studied as biodegradable, is demonstrated. [ABSTRACT FROM AUTHOR]

The present study aims to synthesize a hybrid thin film with sol-gel process via dip-coating and spin-coating techniques. Prepared films are used in the elimination several pollutants using the photodegradation process. Used films are prepared by mixing polyvinyl chloride (PVC)/hydrophobic-modified clays (Hc). First, we modified natural bentonite (Bt) and sodium montmorillonite (Na-Mt) with a surfactant cetyltrimethylammonium bromide. incorporation of methylene blue (MB) as photosensitizers into Hc was realised with different percentage of hydrophobic clay/photosensitizers at ambient temperature and optimum pH for 3 h. Secondly, the PVC/modified clay thin films were elaborated with sol-gel technology, using two techniques for deposition: Dip-coating in dimethylformamide and spin-coating in tetrahydrofuran. We modified some parameters such as weight ratio polymer/modified clay, number of dipper, rotational velocity, viscosity of polymer solution, rotation time and ramping -up rate for optimum conditions. Prepared films are characterized by X-ray diffraction, scanning electron microscopy-X-ray fluorescence and Fourier-transform infrared spectroscopy, the obtained results show the good insertion of MB into different support. The deposition on PVC increase the distance basal of materials. The efficiency of our prepared films was evaluated through the degradation of some dyes such as tartrazine (TR) and methyl orange (MO), using photoreactor upon irradiation with visible light and air injection. The obtained results show a significant efficiency of the films in the degradation of MO and TR. The TR degradation yields obtained vary from 72% to 76% for films containing 5% MB, and a yield close to 99% for the degradation of MO. [ABSTRACT FROM AUTHOR]

In this study, the preparation of thermally stable organic-inorganic hybrid nanocomposites from chemically functionalized oxidized graphite is carried out by in-situ catalytic oxidative decarboxylation of 3,5-dinitrobenzoic acid (reactant) in the presence of potassium persulfate (oxidant), silver nitrate (catalyst) and graphite (support) under thermal or microwave conditions. The effects of heat transfer and dosages of reactant, catalyst and oxidant on the crystalline structure and the morphology of nanocomposites are studied in detail. The prepared nanocomposites are characterized by EDS, elemental mapping, FE-SEM, FT-IR and XRD. The thermal stability of nanocomposites is examined by TGA and DSC. EDS shows that nanocomposites are composed of C, O, N, S, K and Ag elements. FT-IR exhibits that the graphitic layers in nanocomposites are mainly oxidized and functionalized with carboxyl, carbonyl, hydroxyl, epoxy, sulfate, nitrate and nitroaryl groups. Addition of nitroaryl groups to nanocomposites is also supported by an increase found in their C and N contents. XRD demonstrates the coexistence of both oxidized amorphous carbon and graphite in combination with different levels of organic and inorganic phases. The prepared nanocomposites show good thermal stability. The total area of the DSC curve in these nanocomposites compared to graphite is enhanced. [ABSTRACT FROM AUTHOR]

When drilling into a reservoir, the drilling fluid containing bentonite is prone to solid phase invasion, causing serious damage to the reservoir, and the conventional API barite suspension stability is poor, which makes it easy to cause sedimentation and blockage. Therefore, in order to avoid accidents, we use ultrafine barite to obtain a good suspension stability. More importantly, the method of modifying zwitterionic polymers on the surface of nano-silica is used to develop a temperature-resistant and salt-resistant fluid loss reducer FATG with a core-shell structure, and it is applied to ultra-fine clay-free water-based drilling fluid (WBDF). The results show that the filtration loss of clay-free drilling fluid containing FATG can be reduced to 8.2 mL, and AV can be reduced to 22 mPa·s. Although the viscosity is reduced, FATG can reduce the filter loss by forming a dense mud cake. The clay-free drilling fluid system obtained by further adding sepiolite can reduce the filtration loss to 3.8 mL. After aging at 220 °C for 15 d, it still has significant salt tolerance, the filtration loss is only 9 mL, the viscosity does not change much, a thinner and denser mud cake is formed, and the viscosity coefficient of the mud cake is smaller. The linear expansion test and permeability recovery evaluation were carried out. The hydration expansion inhibition rate of bentonite can reach 72.5%, and the permeability recovery rate can reach 77.9%, which can meet the long-term drilling fluid circulation work in the actual drilling process. This study can provide guidance for technical research in related fields such as reservoir protection. [ABSTRACT FROM AUTHOR]

In this study, a natural smectite extracted from El Hicha deposit in the Gabes region located in southeast of Tunisia was firstly purified and then modified by ion exchange with didodecyldimethylammonium bromide (DDDMA) under microwave irradiation in order to obtain an efficient organoclay for removing from aqueous solution of diuron. The characterization of the purified clay (HP) and the modified one (HMD) were performed by several technics such as X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), scanning electron microscope (SEM), and N2 adsorption–desorption isotherms. The diuron adsorption tests undertaken in batch mode revealed that the diuron herbicide did not adsorbed by HP. While it was well adsorbed by the HMD thanks to its hydrophobic character and positively charged surface created by the loaded cationic surfactant molecules. In addition, diuron adsorption did not depend on the aqueous solution pH (2.7–11.8) and only slightly on the temperature medium. Nevertheless, it increased with the raising of contact time, the initial diuron concentration, and the dose of organoclay. The results obtained at equilibrium at room temperature were well described by the Langmuir model with a maximum adsorption capacity about of 110 mg/g. Kinetic studies demonstrated that the diuron adsorption was best described by the pseudo-second order kinetic model. Finally, the obtained results showed the effectiveness of HMD as an adsorbent for the elimination of diuron from aqueous solution. [ABSTRACT FROM AUTHOR]

In an effort to mitigate the harm caused by the irregular use of agrochemicals, a safer release system using biopolymers is promising due to their availability, biodegradability, and eco-friendliness. Herein, controlled-release materials for NPK fertilizer were formulated using clay-based graft biopolymer composites. The clay soil sample was collected and classified through Skempton's laboratory tests for soils and used as filler in starch-grafted sodium alginate (ST-g-SAG) with different percentages of clay. The clay-based graft biopolymer composites were synthesized via a microwave-assisted method. The biopolymer composites were characterized by FTIR, SEM, and EDS. The materials were loaded with NPK fertilizer, and a leaching test was conducted via a conductometric method to ascertain their release capacities. Biodegradation studies and the effect of humidity on the release of the NPK fertilizer were studied. Results of classification studies of the clay show Ca-montmorillonite (Ca-MMT) type. The average percent graft yield of starch-grafted sodium alginate/Ca-MMT (ST-g-SAG/Ca-MMT) was 83%. The results from FTIR and EDS showed that OH-, COO-, and CONH2 were responsible for the absorption of water. The release profile of the active NPK in the biocomposites ranged from 1% to 103%. Biodegradation results also showed a significant breakdown in biopolymer structure and mass loss. The release of active NPK from the material was humidity-responsive. [ABSTRACT FROM AUTHOR]

Linear low‐density polyethylene (LLDPE) and high‐density polyethylene (HDPE) are polyolefins widely used in the packaging sector. Seeking to improve the mechanical properties with good cost‐effectiveness, attapulgite (ATP) was chosen as a reinforcing filler for the polyolefins. ATP is a hydrated magnesium and aluminum clay mineral with a microfibrous morphology, and the purity of this filler depends on the deposit. ATP is associated with the presence of accessory minerals that need to be removed so as not to interfere with its final application. Thus, an ATP purification process was carried out through physical separation and chemical treatment with hydrogen peroxide (H2O2) and sulfuric acid (H2SO4). This purification process despite having a low yield and is very effective in reducing impurities and organic matter. This ATP was named ATPa. LLDPE/ATPa and HDPE/ATPa nanocomposites with the addition of 1, 3, and 5 wt% of ATPa were prepared by extrusion and hot pressing. The mechanical properties (Shore D hardness, tensile tests, and Izod impact strength), thermal properties (differential scanning calorimetry—DSC and thermogravimetric analysis—TGA), X‐ray diffraction, rheological, and transmission scanning microscopy (TEM) were determined for these nanocomposites. The mechanical properties of the nanocomposites increased with the addition of ATPa. HDPE/ATPa nanocomposites showed more promise than LLDPE/ATPa nanocomposites. The addition of 5 wt% ATPa increased the tensile strength by 14% for the HDPE matrix and 5% for the LLDPE matrix and increased the elastic modulus by 46% for HDPE and 26% for LLDPE. [ABSTRACT FROM AUTHOR]

Starch is an essential biopolymer in biofuel production and a sizing agent in the paper and textile industries. However, native starch is unsuitable for most applications due to brittleness, inferior mechanical and thermal properties, and poor processability. In this regard, a series of modified starch‐based biopolymer composites were prepared by extrusion to produce composites with enhanced properties for enlarged applications. Unlike other studies, the developed thermoplastic starch (TPS) in this work was produced by gelatinizing starch with glycerol and poly(butylene succinate) (PBS) to induce both plasticization and compatibilization. The resultant TPS was blended with diverse organoclays and polylactide (PLA) via a twin‐screw extruder to obtain TPS/PLA/organoclay composites. The ensuing composites were studied for thermal and morphology properties using thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), scanning electron microscopy (SEM), and transmission electron microscopy (TEM). Results showed that the organoclay loading highly influenced the mechanical and thermal properties of the TPS/PLA composites by enhancing the thermal stability and stiffness of the blends. More importantly, incorporating a small amount of organoclay into PLA enhanced its compatibility with TPS, as depicted in morphological studies. The enhanced crystallization and compatibilization of the blends resulted in enhanced mechanical properties of eco‐friendly composite materials for sustainable packaging applications. [ABSTRACT FROM AUTHOR]

Apart from the inherent anomalous behaviour under tensile and compressive structures, auxetic structures have shown improved energy absorption characteristics that are of prime interest to various fields of study. This is further exemplified by additive manufacturing (AM) techniques and polymer composites to tailor the shape, geometry and form of these structures. Consequently, this paper aims to characterise the in-plane compressive behaviour and negative Poisson's ratio (NPR) of the most prominent auxetic structures fabricated additively used polymer nanocomposite materials. The study incorporates the use of glycol-modified polyethylene terephthalate (PETG) and nanocomposites of PETG filled with organically modified montmorillonite (OMMT) nanoclay particles to produce auxetic structures fabricated through fused filament fabrication (FFF). Different structures such as hexagonal re-entrant honeycomb structures, peanut-shaped honeycombs, chiral honeycomb structures and missing rib structures are characterised for their compressive performance through experimental approaches involving mechanical testing and digital image correlation (DIC). Different parameters such as the peak crushing strength, average crushing strength, NPR, specific energy absorption (SEA), and crush force efficiency (CFE) of these structures are evaluated at different strain rates/loading rates for varying concentrations of nanoclay and PETG. It is observed that higher loadings of nanoclay particles lower the compressive strength of the structures. Additionally, the NPR decreases with increasing strain rates and is also influenced by the composition and the resultant stiffness. Moreover, the geometrical parameters of the structure largely influence its strain energy absorption. The results have shown that such material-structure combinations can produce structures of high-performance capabilities suitable for aerospace applications. [ABSTRACT FROM AUTHOR]

High‐density polyethylene (HDPE) is a popular material for use in medical, packaging, and construction applications due to its low cost and good processing characteristics. Its chemical stability and resistance make it particularly suitable for use in storage tanks for chemicals and gases. However, its low gas barrier properties and limited strength have hindered its widespread use in such applications. This study puts forward a novel approach, micro‐nano torsional laminated extrusion (MNTLE), for preparing HDPE/montmorillonite (MMT) nanocomposites with improved mechanical and gas barrier properties. The MNTLE method yields a more uniform of fillers in the composites, which leads to greater mechanical strength (a 46.18% increase in tensile strength and a 27.37% rise in elongation break), along with a higher crystallinity (a 16.27% increase) compared to compression molding. Moreover, the improved dispersion and orientation of the Nano‐MMT in composites fabricated by MNTLE lead to a 41.9% reduction in oxygen permeability compared to press‐molded composites. Consequently, this study introduces an innovative processing method that enhances the mechanical and gas barrier characteristics of the material, thus offering potential applications in the manufacturing of lining materials for Type IV hydrogen storage tanks. Highlights: The MNTLE method is used to process composites.The MNTLE significantly improves the dispersibility of the filler.Mechanical properties of composites processed by MNTLE are enhanced.The crystallinity of the reinforced composite increased by 16.27%.The oxygen permeability of the composite prepared by MNTLE is reduced. [ABSTRACT FROM AUTHOR]

In this study, the influence of the organoclay (OC) nano-fillers (Cloisite 15A (CE15A), Cloisite 20A (CE20A), and Cloisite 30B (CE30B)) on the cure and swelling behaviors, compression set, abrasion resistance, and mechanical properties of a blend of 50/50 ethylene-propylene-diene monomer and acrylonitrile-butadiene rubber (EPDM/NBR) has been examined. It has been noted that the maximum torque values increase as filler loading increases. Comparing filled nanocomposites to unfilled samples, it has been observed that filled systems have a lower tendency to absorb solvent. Due to improved filler reinforcement, nanocomposites reinforced with CE30B showed the least solvent uptake across OC filled systems. The morphology of the CE30B-filled samples was more homogeneous when compared to the other (CE15A and CE20A) filler-reinforced nanocomposites. The mechanical properties of the CE30B-filled samples, followed by those of the CE20A and CE15A-filled systems, improved the most. This has been explained by CE30B OC's increased interaction between nanofiller and rubber matrix. Mechanical testing experimental results have been contrasted with various theoretical models. [ABSTRACT FROM AUTHOR]

The use of organically modified clays as nano-reinforcement in polymer matrices is widely investigated owing to their remarkable reinforcement at low filler loading. In this body of work, the nanocomposites were prepared by melt blending nanoclay with polyamide 11 (PA 11) utilising a twin-screw extruder in order to maximise the dispersion of clay particles within the matrix during compounding. The main aim of the work was to study the reinforcing effect of nanoclay within PA 11 using two micromechanical model namely Halpin-Tsai and Mori-Tanaka composite theories. These theories were used to predict the effective tensile modulus of PA 11 nanocomposites and the results were compared to the experimental data. In addition, the Halpin-Tsai model was used to predict the storage modulus and heat distortion temperature (HDT) of PA 11 nanocomposites. It was found that the tensile modulus for nanocomposites with a high clay aspect ratio exhibits up to 10% higher when compared to the nanocomposites with lower clay aspect ratio. Thus, it is believed that the combination of clay aspect ratio and modulus contributes to the super reinforcing effect of nanoclay within the PA 11 matrix. [ABSTRACT FROM AUTHOR]

Herein, bionanocomposites of chitosan (CS)/silver nanoparticle/organoclay/zinc oxide nanoparticle (CS/Ag/OC/ZnO) were prepared for antibacterial food packaging. This study examines the time variation in the AgNP synthesis method by comparing local (74-85% deacetylated) and commercial chitosan (75%-85% deacetylated) as a reducing and capping agent and seeks to reconstruct the optimum ratio formulations of AgNPs and ZnONPs in bionanocomposites for food packaging. The results reveal that the synthesis of AgNPs was successfully carried out using a local chitosan solution as a reducing and capping agent. The CS/Ag/OC/ZnO films exhibit structural, mechanical, and optical properties suitable for food packaging and antibacterial activity on Staphylococcus aureus and Escherichia coli. The relative inhibition zone increased with increasing numbers of AgNPs and ZnONPs. The inhibition zone values indicated that E. coli and S. aureus bacteria were sensitive to the film, namely 12.5 ± 1.5 mm, and 16 ± 0.0 mm, respectively. [ABSTRACT FROM AUTHOR]

The paper discusses the development of a multiscale computational model for predicting the permeability of multilayer protective films consisting of multiple polymeric and hybrid layers containing clay minerals as fillers. The presented approach combines three levels of computation: continuous, full atomic, and quantitative structure–property correlations (QSPR). Oxygen and water are chosen as penetrant molecules. The main predictions are made using the continuum model, which takes into account the real scales of films and nanoparticles. It is shown that reliable predictions of the permeability coefficients can be obtained for oxygen molecules, which is not always possible for water. The latter requires the refinement of existing QSPR methods and interatomic interaction potentials for the atomistic level of calculations. Nevertheless, we show that the maximum effect on permeability reduction from the addition of clay fillers to the hybrid layer can be achieved by using nanoparticles with large aspect ratios and a high degree of orientational order. In addition, the use of the hybrid layer should be combined with the use of polymer layers with minimal oxygen and water permeability. The constructed model can be used to improve the properties of protective coatings for food and drug storage and to regulate the gas permeability of polymeric materials. [ABSTRACT FROM AUTHOR]

Polymeric epoxy-based nanocomposites have tremendously grown in electronic and indoor high-voltage insulation applications over the last two decades. The interface between the epoxy resin and inorganic fillers surprisingly improves the performance compared to neat epoxy and conventional ceramic insulators. However, several configurations, including the filler loading, filler size, and synthesis process, substantially impact performance. Dielectrics employed in power equipment are often exposed to corona discharges, causing surface erosion and may cause flashover due to prolonged exposure to the discharges. Also, dielectrics must continuously endure heat from leakage currents or surrounding temperatures. The present work examines various configurations of the epoxy/ZnO composites for the corona discharge resistance and thermal stability: the effect of filler loading, preparation method of nanocomposites, and co-filling of nano-micro fillers. The ZnO nanoparticles were disseminated in the epoxy resin using a probe and bath sonicator with and without solvent. It also includes the impact of heated nanoparticles. The corona discharge tests were performed using a set-up similar to CIGRE working group D1.24. The studies of surface degradation were conducted using surface roughness metrics obtained from an optical 3D profilometer. Differential scanning calorimetry (DSC) was used to perform the thermal analyses as per ASTM E1356. It was found that compared to all the filled specimens, the neat epoxy experienced more severe erosion. In addition, the specimen filled with ZnO nanoparticles endured positive corona discharges compared to negative and AC discharges. The specimen prepared with heated nanoparticles without solvent using a probe sonicator showed high heat energy and heat capacity leading to thermal instability. Besides, the interface between nano-micro particles and the host material increases corona discharge resistance and thermal stability. [ABSTRACT FROM AUTHOR]

This research evaluates the use of organoclay/alginate hydrogels in removing Acid Yellow 23 in a fixed-bed column and contributes to the application of these composites in the context of the adsorption of anionic dyes that are present in wastewater. An organobentonite (OBent) was synthesized and encapsulated in an alginate matrix, using Ca2+ ions as a crosslinking agent. Experiments in fixed-bed columns showed that breakthrough and exhaustion times were longer with increasing bed height, which decreased with increases in flow rate and initial dye concentration. The Thomas, Yoon–Nelson, and Adams–Bohart models were well fitted to the experimental data for the breakthrough curves with high Adj. R2 correlation coefficients and low values of χ2. The theoretical adsorption capacity of the organobentonite/alginate hydrogel calculated from the Thomas model was 0.50 ± 0.01 mg/g (equivalent to 30.97 mg/g OBent), and this was obtained by using a 15 cm (10.10 g) bed height, 1 mL/min flow rate, and a 45 mg/L input dye concentration. The bed was regenerated with a 0.5 M NaOH solution, and the reuse of the saturated column bed was studied for two adsorption–desorption cycles. The results obtained in this study suggest the potential use of an organoclay/alginate hydrogel for the adsorption of pollutants in continuous systems. [ABSTRACT FROM AUTHOR]

This work evaluates the chemical impact of polyethylene terephthalate (PET) as plastic waste material used in clayey soil improvement. The purpose of this work is to study the behaviour of PET added in different percentages in soil, and how it affects the chemical composition of soil by applying rapid ageing cycles. The thermal stability of the clay-PET mixtures using the thermogravimetric method was studied, and the impact of PET quantity on pH was measured. To detect the migration of PET degradation products to the soil gas chromatography with mass spectrometry (GC-MS) was used. The GC-MS analysis results indicate the presence of DIBP, the concentration increased proportionally with the amount of PET added to the clay. The thermogravimetric analysis shows a thermal degradation of the polymeric chain starting from 200 °C. [ABSTRACT FROM AUTHOR]

This study used ethylene‐propylene diene monomers (EPDM), an elastomer, to develop foams incorporating clay as filler using simple compounding, chemical foaming, and peroxide‐mediated light crosslinking methods. The low‐temperature batch mixer was employed for compounding azodicarbonamide (ADC) as a foaming agent, dicumyl peroxide (DCP) as a crosslinker, followed by compression molding for sheet preparation and the high‐temperature foaming process. Fourier transform infrared spectroscopy (FTIR) equipped with a hot stage attenuated total reflection (ATR) was employed to elucidate the ADC decomposition and foaming. The DCP (0.25 phr) content was optimized based on the foaming expansion ratio (>4) and stability, which was further optimized in conjuncture with clay to generate high‐performance composite foams. The incorporation of 1% organoclay enhances the expansion ratio and specific tensile strength by >7 and ~ 270%, respectively, compared with EPDM foams without clay while displaying a density of 0.11 g/cm3. Overall, the developed foaming process can be extended to other elastomeric polymers for various applications such as protective gears (e.g., helmets and shin guards), thermal/sound insulation, packaging/containment, footwear soles, oil absorption, etc. [ABSTRACT FROM AUTHOR]

In this study, proton‐conducting sulfonated polyether ether ketone (sPEEK) membranes including tungstic acid, organically modified montmorillonite, and silicon dioxide were prepared using solution casting method for direct methanol fuel cells. All obtained composite membranes had adequate thermal stability for fuel cells, and their surfaces became more hydrophilic due to the incorporation of additives. The ion exchange capacities of the composite membranes were found to be very close to the sPEEK membrane. While the proton conductivity of the sPEEK membrane was 8.6 mS cm−1, the addition of additives led to an enhancement in the proton conductivity values. Among the prepared composite membranes, sPEEK‐H2WO4‐5 had the highest proton conductivity (36.5 mS cm−1) which was comparable to Nafion117 in water at room temperature. On the other hand, the methanol permeabilities of the composite membranes were in the same order compared to sPEEK but showed minor changes depending on the added materials and their compositions. Among the membranes obtained by solution casting, sPEEK‐H2WO4‐5 was found to be the best composite membrane due to its high proton conductivity and acceptable methanol permeability. Layer‐by‐layer modified sPEEK membranes were also obtained in the study for comparison and it was found that sPEEK‐PAH/H2WO4‐2 displayed the best selectivity value. [ABSTRACT FROM AUTHOR]

Intending to provide efficient and compact wastewater remediation, the present work is exploiting and introducing a novel composite prepared from porous starch aerogel (PSA) and organically modified Ca-montmorillonite (OMMT) for the removal of dyes from aqueous samples. First, potato starch components were used as a hydrolysis precursor to obtain PSA. The organoclay samples were prepared by co-intercalation of octadecylamine (ODA) into Ca-MMT using a low-temperature melting procedure. Composites with different starch-to-organoclay ratios of 10:1, 1:1, and 1:10 were then prepared by a blending process in distilled water and used for methyl orange (MO) uptake. The removal of methyl orange dyes increased with the amount of organoclay in the PSA matrix. Characterization revealed that organoclay synergy improved the PSA surface chemistry, while an important improvement in textural properties and thermal stability was also observed. The composite’s efficiency was demonstrated by high removal capabilities towards MO in most experimental runs, with a maximum adsorption capacity beyond 344.7 mg/g. The fitting result showed that MO adsorption follows a monolayer adsorption model, and chemisorption was the rate-controlling step. Nonetheless, this study proved the great potential of PSA/OMMT in dyeing wastewater treatment. Furthermore, starch modification is proven as an effective approach to enhancing the performance of starch-derived adsorbents.

Current interest in dispersion strategies for nanoparticle fillers is driving research into covalently attached polymer brushes. The primary need for these "hairy nanoparticles" is for testing and developing new technologies based on polymer nanocomposites. To that end, we have prepared polymer nanocomposites with covalently tethered chains on a naturally occurring montmorillonite clay template via a metal-mediated surface-initiated ring opening metathesis polymerization approach. The nanocomposites were characterized in terms of polymer:clay composition and of various chain architecture parameters such as molecular weight, polydispersity index, and grafting density. [ABSTRACT FROM AUTHOR]

Poly(amic acid) (PAA), a precursor of polyimide (PI), is synthesized by reacting dianhydride 4-(2,5-dioxotetrahydrofuran-3-yl)-1,2,3,4-tetrahydronaphthalene-1,2-dicarboxylic anhydride with diamine 3,3′-dihydroxybenzidine in N,N′-dimethylacetamide. Organoclays with different alkyl chain lengths were dispersed in PAA, and the weight percentages (wt%) of the organoclays varied. The PI hybrid films were prepared over multiple steps under heat treatment conditions. Bentonite (BTN) was used as the pristine clay, and octylamine (C8) and hexadecylamine (C16) were used to chemically modify the surface of BTN to obtain the desired organoclay samples. Organoclays C8-BTN and C16-BTN were dispersed in a PI matrix, and the organoclay content varied in the range of 1–9 wt%. The thermal, morphological, and optical properties of the PI hybrid films were investigated based on the organoclay content. Although the thermal stability of the PI hybrid film improved when a small amount of organoclay was added, it decreased when the nano-filler content exceeded a certain critical content. Specifically, in the hybrid containing C8-BTN, the critical content is 5 wt%, while in the hybrid with C16-BTN, the critical content is 7 wt%. In addition, the morphology of the clay dispersed in the matrix at the critical content showed the best dispersed phase. The physical properties (thermal characteristics, dispersibility, and optical transparency) of the PI hybrid film containing C16-BTN were better than those of the hybrid film containing C8-BTN. However, the thermal expansion of the C8-BTN hybrid was lower than that of the C16-BTN film at the same content.

This article narrates how processing "bias" affects polymer chain dynamics due to variable 2D-nanofiller interfaces. Importance of this biasing can be assessed by the significant improvement in thermal and mechanical properties we have recently published for polyurethane-2D clay nanocomposite coatings. We intricately look at the nanoscale structure and subsequent interface formation between 2D clay and PU chains to understand the changes in morphology. Polyurethane (PU) chain dynamics was observed through the gold (Au) sputtered patterns in field emission electron microscopy (FESEM) images. These were fitted with circles and our findings confirm the presence of an attractive interface between PU and 2D nanoclay. Circle fitting elicits important data like the critical area ( A c ) and critical relative frequency ( f c ) which are used to evaluate the polymer chain dynamics and morphology. We find that f c is related to circularity, and reinforcing nanoclay to the PU matrix enhances f c by 4.6% and 6.9% with simultaneous use of ultrasonic bath and high shear homogenizer. This is further correlated with the already established methods of small angle X-Ray scattering (SAXS) and Fourier transform infrared (FTIR) spectroscopy to generate a fresh perspective on interfacial interactions in PU-2D clay nanocomposites. Circle fitting treatment FESEM images of polyurethane (PU) nanocomposites. Difference in the gold sputtering patterns (GSPs) of PU on the surface of nanoclay (below) can be clearly observed as compared to the GSPs of bare PU (above). 1 wt% C30B-PU nanocomposite coatings were prepared using 3 processing schemes. FESEM images revealed gold sputtered patterns from the differently processed samples. Circle fitting analysis on GSPs helped in understanding the polymer nanofiller interface. Growth conformation of polymer chains in and around the 2D nanofiller provides fresh perspective into polymer chain dynamics. [ABSTRACT FROM AUTHOR]

The aggregation process of 2D nanofillers (organoclay and graphene oxide (GO)) is studied within the framework of micromechanical models. The degree of aggregation of these nanofillers, expressed as the number of individual plates in one aggregate (tactoid), is determined by the ratio of the nominal moduli of elasticity of the nanofiller and the matrix polymer. It is found that increasing the first of these moduli leads to an increase in the degree of aggregation, whereas increasing the second one, leads to its reduction. This means that it is practically impossible to obtain exfoliated (separate) graphene plates in a polymer matrix. Both the studied polymer/2D nanofiller nanocomposites are reinforced with separate nanofiller aggregates, which is the optimal variant of reinforcing them. [ABSTRACT FROM AUTHOR]

This study aimed to create CTAB-modified bentonite organoclay (Bt@CTAB) by mixing the naturally occurring mineral bentonite (Bt) with the cationic surfactant cetyltrimethylammonium bromide (CTAB). Elemental analysis, N2 adsorption–desorption isotherm, scanning electron microscopy (SEM), FTIR spectroscopy, XRD, and thermogravimetric (TGA) analysis have been employed to analyze both the unmodified Bt and the Bt@CTAB organoclay. The dye sorption onto Bt@CTAB organoclay was investigated in the batch and column modes using aqueous solutions of anionic food dyes, viz., Sunset yellow FCF (E110), Azorubine (E122), and Ponceau 4R (E124) (individually or in a mixture). Experimental variables affecting the adsorption process, such as initial dye concentration, contact time, temperature, pH, and adsorbent dose, are evaluated. From the kinetic investigations, the adsorption of E110, E122, and E124 dyes well matched the pseudo-second-order kinetic model. E110 and E122 dyes adsorption onto Bt@CTAB attained equilibrium in 120 min while attained in 240 min for E124. The investigated food dyes were expected to achieve maximum adsorption efficiencies at concentration of 100 ppm of (E110 and E124) and 150 ppm of (E124), an adsorbent dosage of 0.4 gL−1, and an initial pH 5. In addition, Langmuir model best fits the sorption isotherm data, with the maximum adsorption capacity at 303 K being 238 mg/g, 248.75 mg/g, and 358.25 mg/g for E110, E122, and E124, respectively. The Bt@CTAB organoclay can be regenerated up to the 4th cycle successfully. The thermodynamic studies revealed the spontaneous and exothermic nature of the adsorption of these anionic dyes onto Bt@CTAB organoclay. The prepared cationic Bt@CTAB organoclay was successfully applied for the removal of E110, E122, and E124 from real water samples, synthetic effluents, and colored soft drinks with a recovery (R%) higher than 95%. The plausible adsorption mechanism of E110, E122, and E124 onto Bt@CTAB organoclay is proposed to be due to electrostatic interaction and hydrogen bond formation. Finally, the present study shows that Bt@CTAB organoclay may be employed efficiently and effectively to remove anionic food dyes from a wide range of real water and colored soft drinks. [ABSTRACT FROM AUTHOR]

Clay modification by organic ammonium salts has been widely introduced in rubber/clay nanocomposites, but it is inapplicable in the polar rubbers to achieve high performance due to bad dispersion and poor compatibility. In this work, gel‐compounding method was utilized to prepare nitrile butadiene rubber (NBR)/clay nanocomposite, and then a hindered phenol antioxidant, triethylene glycol bis(3‐tert‐butyl‐4‐hydroxy‐5‐methylphenyl)propionate (AO‐245) with various contents, was mechanically blended to enhance the interactions in the nanocomposites. The elongation at break increases while the Shore A hardness, permanent set and stress at 100% or 300% strain decrease by adding AO‐245 into the nanocomposites. By adding only 5 phr AO‐245 in the nanocomposite, the tensile strength and elongation at break increased from 18.3 MPa and 521% to 20.5 MPa and 646%, respectively, which resulted from the repeated destruction/construction of the hydrogen bonds between AO‐245 and NBR. At high AO‐245 content, both clay networks and AO‐245 aggregate networks coexist in the nanocomposite, and the excess AO‐245 in the NBR matrix can form a separated phase leading to a new internal friction peak. [ABSTRACT FROM AUTHOR]

In this work, nanocomposites of polyvinyl chloride poly(epichlorohydrin-co-ethylene oxide)(ECO)/organoclay were prepared via melt processing and various parameters including nanoclay and rubber content (ECO) as well as rotor speed were tuned to find the optimum formulation for the highest thermal stability. The prepared products were characterized by X-ray diffraction as well as thermogravimetric analysis (TGA), derivative thermogravimetric (DTG) and differential thermal analysis XRD results showed that rotor speeds higher than 70 r/min are crucial for obtaining highly intercalated products with good thermal stability. From DTG analyses, it was observed that at lower concentrations of rubber, the rate of mass loss is higher which results in faster dehydrochlorination of the composite. The sample prepared with 2 phr OMMT, 30 phr rubber, and 70 r/min rotor speed showed the highest thermal stability. The selected nanocomposite showed the first weight loss at 294 ℃. Results of this research showed that even a slight change in each parameter has a great influence on thermal properties of the nanocomposites. The hydrogen bonding mode between ECO and organoclay were estimated by theoretical calculations using GAUSSIAN software. From the obtained results, the miscibility of OMMT and ECO polymer is related to the hydrogen bonds which are more preferred at chlorine atom of ECO polymer. [ABSTRACT FROM AUTHOR]

This work focuses on the preparation and characterization of new poly(GMA)@Fe3O4 and poly(GMA)@Fe3O4-NH2 nanocomposites. Firstly, the magnetite was synthesized and functionalized by different aminosilanes (mono, di and triamine); then, different percentages of these materials were dispersed by ultrasound in the poly(GMA) matrix. The structural, thermal and morphological properties of obtained composites were evaluated. For this, different characterizations such as Fourier transform infrared spectroscopy, X-ray diffraction, X-ray photoelectron spectrometry, scanning electronic microscopy and thermogravimetric analysis were employed. It was shown that the aminosilanes nature, the percentage of nanofillers and the use of ultrasonic treatment play a very important role in the structural, thermal and morphological properties of the obtained composites; the results show that the best composites with improved stabilities were obtained by Fe3O4 and NH2-Fe3O4 functionalized by monoamine as nanofillers. The yields of the obtained composites were very high in a lower reaction time, which is mainly due to the sonication process. The use of ultrasound also allowed preserving the epoxy ring known to be a very reactive function and an easily opened ring; this huge advantage will allow a possible modification of these composites for any application. [ABSTRACT FROM AUTHOR]

A method of montmorillonite modification with polar oligourethane containing reactive amino groups has been developed. It is shown that functionalized montmorillonite is capable of adding aromatic and aliphatic diisocyanates, as well as sequential addition of aromatic diisocyanates and glycerol, which is essential for montmorillonite application as filler for polymer materials. According to wide-angle X-ray scattering, interlayer distance d001 of montmorillonite in the obtained samples varies depending on nature of oligomer macromolecules in the interlayer space that is explained with different conformation and orientation of aromatic and aliphatic oligourethane fragments. [ABSTRACT FROM AUTHOR]

This review offers a summary of the epoxy-nanoclay nanocomposites research that has been performed. Epoxy-nanoclay nanocomposites have an across-the-board variety of aerospace, defense, construction, and automobile applications. Nanoclay is one of the ideal nano-reinforcement for epoxy because of its ease of workability, environmental accessibility, well-versed chemistry, and lower cost. The significant addition of a smaller quantity of nanoclay, mostly ≤5 wt.%, may efficiently improve polymer composites' properties. This review aims to provide a state-of-the-art overview of epoxy-nanoclay nanocomposites, including their preparation methods, mechanical, hygrothermal, and wear properties. The discussion highlights the nanoclay influence on the properties listed above and the morphology of epoxy-nanoclay nanocomposites. [ABSTRACT FROM AUTHOR]

The nature of interactions of a toxic dye, thioflavin T (TFT), with pristine clay (bentonite (Bet)), clay minerals (montmorillonite (Mnt) and vermiculite (Vt)) and their organically modified forms (OMnt, OBet and OVt) has been investigated in aqueous media, and a methodology was developed for the utilization of TFT-treated colored residues as nanopigments, without producing the second-generation waste materials. The uptake of TFT was found to be more in case of pristine clay and clay minerals than their organically modified forms. In case of Mnt, TFT was present in the interlayer region, as supported by XRD data, and on the surface as the surface charge of TFT-treated pristine Mnt became almost zero, as indicated by the change in zeta potential value (− 17.6 to − 0.03 mV). In case of Bet and Vt, TFT was found to be only on clay mineral's surface, as suggested by the change in zeta potential value (− 31 to − 0.6 mV in case of Bet and − 47 to − 0.04 mV in case of Vt). The corresponding increase in the particle size (158–443 nm in case of Bet and 145–460 nm in case of Vt) was also evocative of surface adsorption. In case of organically modified forms (OMnt, OBet and OVt), TFT was predominantly on the surface in all cases examined. The experimental data obtained during extractive removal of TFT using pristine and organically modified clays were best described with Langmuir adsorption isotherm model, whereas kinetic data are equipped with pseudo-second-order kinetic model. The intense yellow-colored solid material obtained after the extraction was used as colorant for the formation of polymer films with enhanced physico-chemical characteristics. These materials not only provide beautiful bright color but also prevent the accumulation of second-generation waste material. [ABSTRACT FROM AUTHOR]

To prevent the serious threat of textile wastewater, researchers have developed adsorption-based wastewater treatment using cheap, yet effective, adsorbent materials. Of which is natural bentonite, that has the advantages for adsorption due to its porous structure and functional groups but still suffers from its low affinity against anionic and hydrophilic azo dyes. Herein, we aimed of improving the affinity by amino acid tryptophan embedment into the locally isolated natural bentonite collected from Aceh Province, Indonesia. The prepared bentonite samples were characterized using Fourier transform infrared, X-ray diffraction, and scanning electron microscopy. Adsorptive removal was performed on naphthol blue black (NBB) in a batch system with variations of contact time, pH, and adsorbent dosage. The isotherm studies were carried out at optimum conditions (contact time=15 minutes; pH 1; adsorbent dosage=0.2 g) with several models including Langmuir, Freundlich, Sips, and Redlich-Peterson isotherm models. The characterization results revealed that the modification altered its functional group, crystallinity, and micro-surface morphology that add more benefits for adsorption. At optimum conditions, 99.2% NBB has been successfully removed from the aqueous solution. The isotherm studies suggested that the NBB adsorption onto the tryptophane-modified natural bentonite was dependent on Sips isotherm model (R2=0.999; root-meansquare-errors=1.11×10-4 mg/g). [ABSTRACT FROM AUTHOR]

Intending to provide efficient and compact wastewater remediation, the present work is exploiting and introducing a novel composite prepared from porous starch aerogel (PSA) and organically modified Ca-montmorillonite (OMMT) for the removal of dyes from aqueous samples. First, potato starch components were used as a hydrolysis precursor to obtain PSA. The organoclay samples were prepared by co-intercalation of octadecylamine (ODA) into Ca-MMT using a low-temperature melting procedure. Composites with different starch-to-organoclay ratios of 10:1, 1:1, and 1:10 were then prepared by a blending process in distilled water and used for methyl orange (MO) uptake. The removal of methyl orange dyes increased with the amount of organoclay in the PSA matrix. Characterization revealed that organoclay synergy improved the PSA surface chemistry, while an important improvement in textural properties and thermal stability was also observed. The composite's efficiency was demonstrated by high removal capabilities towards MO in most experimental runs, with a maximum adsorption capacity beyond 344.7 mg/g. The fitting result showed that MO adsorption follows a monolayer adsorption model, and chemisorption was the rate-controlling step. Nonetheless, this study proved the great potential of PSA/OMMT in dyeing wastewater treatment. Furthermore, starch modification is proven as an effective approach to enhancing the performance of starch-derived adsorbents. [ABSTRACT FROM AUTHOR]

Composites based on high-pressure polyethylene and ethylene–vinyl acetate copolymer containing a sepiolite clay powder with a chain-layered structure are studied, and an analysis of their physical and mechanical properties is carried out. No organomodification and compatibilization are required in the case of using sepiolite. It is shown that composite materials with the addition of sepiolite are superior with respect to a series of characteristics to composite materials containing conventionally applied layered clay powders. [ABSTRACT FROM AUTHOR]