Clay Nanocomposites Research Articles

Synthesis and Evaluation of Starch-Grafted-Poly[(Acrylic Acid)-Co-Acrylamide] Based Nanoclay Polymer Composite Fertilizers for Slow Release of Nitrogen in Soil

Nitrogen (N) losses from conventional N fertilizers contribute to environmental degradation and low N use efficiency. Highlighting the need for slow-release fertilizers (SRFs) to mitigate these problems, this study aims to develop slow-release N fertilizers using starch-grafted-poly[(acrylic acid)-co-acrylamide] based nanoclay polymer composites (NCPCs) and investigate their efficacy for slow N delivery in soil. Three types of NCPCs, NCPC(A) (poly [(acrylic acid)-co-acrylamide]), NCPC(W) (wheat starch-grafted-poly[(acrylic acid)-co-acrylamide), and NCPC(M) (maize starch-grafted-poly[(acrylic acid)-co-acrylamide) were prepared and characterized using FTIR spectroscopy and X-ray diffraction techniques. N-release behaviour of the products was assessed under two distinct soils, i.e., Assam (Typic Hapludults, pH 4.2) and Delhi (Typic Haplustepts, pH 7.9) soils. Additionally, the effects of varying soil moisture and temperature levels on N release were studied in the Assam soil. The N-release kinetics of the synthesized fertilizers were assessed using zero-order, first-order, Higuchi, and Korsmeyer−Peppas models. Degradability of the NCPCs was evaluated by measuring evolved CO2–C under various soil conditions as an indicator of microbial degradation. The results indicated that NCPC fertilizers significantly slowed down the release of N compared to urea. According to the R2 values obtained, it was evident that the first-order kinetic model most accurately describes the N release from both urea and NCPC-based N fertilizers in the studied soils. Among the formulations, NCPC(A) exhibited the lowest N release (42.94–53.76%), followed by NCPC(M) (51.05–61.70%), NCPC(W) (54.86–67.75%), and urea (74.33–84.27%) after 21 days of incubation. The rate of N release was lower in the Assam soil compared to the Delhi soil, with higher soil moisture and temperature levels accelerating the release. Starch addition improved the biodegradability of the NCPCs, with NCPC(W) showing the highest cumulative CO2-C evolution (18.18–22.62 mg g−1), followed by NCPC(M) (15.54–20.97 mg g−1) and NCPC(A) (10.89–19.53 mg g−1). In conclusion, NCPC-based slow-release fertilizers demonstrated a more gradual N release compared to conventional urea and the inclusion of starch enhanced their degradability in the soil, which confirms their potential for sustainable agricultural applications. However, soil properties and environmental factors influenced the N release and degradation rates of NCPCs.

Synthesis and Applications of Nanocomposites in Food Packaging Industry: A Review

The current review focuses on the applications of polymer nanocomposites in the packing industry. Nanocomposite fabrication may be carried out through several synthetic techniques based on the type of material required. Basically, it is the composite formation of polymeric matrix and a reinforcing nanofiller. The nanoclay used for the modification of nanocomposites acts as a reinforcement or filler. Montmorillonite (MMT) is the most frequently used clay material to obtain the desired properties of nanocomposite. Clay reinforcement enhances the food packing properties of the material because of its properties as flame retardant, tensile features, barrier properties, and biodegradability. Among bottom-up and top-down techniques, sol-gel synthesis, self-assembly, and polymerization are the most common techniques used for the synthesis of nanocomposites. Nanocomposites derived from bio-polymers make the material biodegradable which, in turn, is one of the most desirable features for their future use. Owing to improved characteristics, clay nanocomposites form a superior class of materials for food packaging, yet much finer dispersion of nanofillers and compatibility may be devised.

Nanoclay composites in electrochemical sensors

Nanoclays are layered structures in the nanoscale range with widespread application due to their unique properties such as swelling, cation exchange capacity, and ease of functionalisation using metals, metal oxides, and organic compounds such as carbon paste, polymers, and other biomolecules that form nanoclay composites. Nanoclay functionalisation with silver (Ag), zinc oxide (ZnO), and bimetallic silver–gold (Ag–Au) using hydrophilic and hydrophobic clays is here evaluated and discussed. The composites’ synthesis and morphological, crystallinity, and electroactive properties in comparison with pure nanoclay are also assessed. The layered structure and crystallinity of all these nanoclay composites were slightly changed. The clumped layered structures on the surface of the nanocomposites had dispersed white spots that indicated possible surface modification. The nano-films of the composites’ electroactivity were comparatively high, as seen from the increase in current in the cyclic voltammetry characterisation voltammograms and the differential pulse voltammograms of the pharmaceutical detection. Efavirenz, nevirapine, and zidovudine detection was improved by modification of the nanocomposite with human serum albumin (HSA), as shown by the higher current, thus indicating improved conductivity of the composites compared to the pure nanoclays. Applying HAS-modified nanocomposites in the analysis of efavirenz, nevirapine, and zidovudine on a glassy carbon electrode (GCE) showed good linearity and acceptable detection limits comparable to those of previous studies. Therefore, it has potential for application in pharmaceutical quality control and environmental monitoring.

Removal of Cu(II) from aqueous solutions by novel EDA-functionalized clay nanocomposite fabricated as nanoadsorbents

Removal of Cu(II) from aqueous solutions by novel EDA-functionalized clay nanocomposite fabricated as nanoadsorbents

AI optimization and mathematical simulation validated by nondestructive testing for resonance frequency in advanced composite structures for bridge applications

This paper presents a novel approach integrating artificial intelligence (AI) optimization and mathematical simulation to predict the resonance frequency of nanoclay-reinforced concrete cylindrical shell structures intended for bridge applications. These composite structures, known for their enhanced mechanical properties, require precise evaluation of their vibrational behavior to ensure structural stability and longevity. Traditional methods for predicting resonance frequencies are often time-consuming and prone to inaccuracies, especially in complex materials like nanoclay composites. To address this, an AI-based optimization algorithm was developed, incorporating Particle Swarm Optimization (PSO) and a mathematical modeling to simulate resonance characteristics under varying material and geometric parameters. The mathematical modeling is validated using nondestructive testing (NDT) techniques, such as modal analysis, which provided real-world resonance data without damaging the structure. The nondestructive testing results is compared against the mathematical model to ensure accuracy and reliability. The integration of nanoclay into the concrete matrix significantly altered the vibrational properties, enhancing the stiffness and reducing damping losses, which is crucial for bridge applications where dynamic loads are prevalent. The optimized model not only predicted resonance frequencies with high accuracy but also demonstrated its potential for large-scale bridge infrastructure. This methodology offers a streamlined and robust tool for engineers, reducing the need for physical prototyping and providing enhanced design capabilities. Future research will focus on expanding the model to incorporate additional material behaviors and load conditions, furthering its application in civil engineering.

Adsorption of Uranium (VI) From Aqueous Solution Using Melamine Formaldehyde Organo Clay Nanocomposite Foam as a Novel Adsorbent

Uranium is a toxic radioactive element and is usually found in the environment in hexavalent form. It has become necessary to remove uranium, which can be released into the environment in excessive amounts through nuclear industrial activities, from access waters. Melamine formaldehyde/organo clay nano composite foam (MFCNCF) was prepared as a novel adsorbent by hardening with thermal treatment. Structural, crystallographic textural and surface morphological characterization of the prepared adsorbent was made by Fourier transform infrared spectrophotometry (FTIR), X-Ray diffraction (XRD), Scanning electron microscopy (SEM) and High-resolution transmission electron microscopy (HRTEM) analyses. This study aimed to investigate the adsorption of U(VI) from aqueous solutions by MFCNCF and its dependence on various variables, such as initial uranium concentration, adsorption time, adsorbent dosage, initial pH, and temperature. Additionally, its adsorption isotherm analysis and adsorption kinetics and thermodynamics were also examined. For this purpose, batch adsorption experiments were carried out and the equilibrium concentration of U(VI) in the aqueous solution was measured with a UV-Vis spectrophotometer at a wavelength of 433 nm, which corresponds to its maximum absorptivity. The results regarding adsorption kinetics showed that 30 min was sufficient to reach adsorption equilibrium and the data showed a high fit to the pseudo-second-order kinetic model. Isotherm analysis also revealed a high fit of the data to the Type III isotherm and the Halsey model. Based on these fits, an adsorption mechanism involving two regions (electrostatic and complex formation) is proposed for the current adsorption system. The adsorption isosteric enthalpy and entropy values for the first and second regions were found to be −5.35 and 2.02 kJ/mol and −16.98 and 6.40 J/mol, respectively. The experimental results showed that the prepared nanocomposite foam adsorbent is an effective and potential alternative for the effective removal of U(VI) from aqueous solutions.

Nanocomposites based on MWCNT and nanoclay: Effect of acrylated epoxidized soybean oil on curing and composite properties

UV and thermal-curing hybrid epoxy adhesives are generally developed with a combination of epoxy acrylates and thermal-curing epoxy resin. This study modified bisphenol-A type epoxy resin (ER) with acrylated epoxidized industrial crop soybean oil (AESO) to obtain a dual-curable epoxy system. Hydroxylated multi-walled carbon nanotube (MWCNTOH) and montmorillonite-type nanoclay (NC) first was used as nano reinforcement in this system. Both thermal and UV-curing were applied to composites. Tensile and hardness tests, thermogravimetric analysis (TGA), and four-point probe electrical conductivity measurements were used for the nanocomposite characterization. Although (UV+thermal) curing increased the thermal strength of the nanocomposites, it caused a decrease in their electrical conductivity and moisture absorption. The highest tensile strength values were obtained as 107 MPa and 97 MPa for thermally cured 1.5 wt% MWCNTOH and 2 wt% NC composites, respectively. The effect of the AESO ratio on UV curing of nanocomposites was investigated and 10 % was found to be the most suitable. MWCNTOH composites also exhibited the highest electrical conductivity with a percolation threshold of 1.5 wt%. The effect of hydrothermal aging on thermal and electrical conductivity properties showed that only T5 and T10 values of thermally or (UV+thermally) cured MWCNTOH and NC composites decreased, T50 values did not change significantly.

Preparation, characterization and applications of polyethersulfone/bentonite clay composite for protein removal

In the current work, asymmetric polyethersulfone/bentonite clay nanocomposite (PES/BNT) membranes with differing clay dosages were successfully prepared by the phase inversion method aimed at protein separation. Means of characterization tools were harnessed to validate the fabrication process. The morphology and structure of membranes were examined by scanning electron microscope (SEM) and Fourier-transform infrared spectroscopy (FTIR) while additional surface properties such as pore size, porosity and hydrophilicity measurements were assessed. The permeability-selectivity trade-off of the membranes were assessed to probe the influence of additive content on the ultimate membrane functionality. The results indicated that best membrane performance was achieved with a BNT content of 0.225 g, resulting in enhanced dispersibility within the polymeric matrix. Besides, the inclusion of clay additive led to an increase in pore size ratio in the skin layer, further improving membrane permeability. The optimal membrane exhibited a permeate flux of 20.5 kg.m−2.h−1, while rejected 93 % of bovine serum albumin (BSA). Meanwhile, porosity, pore size and the contact angle measurements have recorded 71.8 %, 22.6 nm and 40.53°, respectively. These findings suggested that the PES/BNT membrane's permeation and separation characteristics, rendering them a viable option for a wide range of water and wastewater treatment applications.

Polycaprolactone, clay and vanadium oxide nanocomposites: development and performance evaluation

Polycaprolactone, clay and vanadium oxide nanocomposites: development and performance evaluation

Release Kinetics of Sulfentrazone from Chitosan Clay Sulfentrazone Nanocomposite

Introduction: With a rational objective to reduce groundwater contamination from pesticides and thereby reducing ecotoxicological effect of pesticide, present research programme was carried out. Sulfentrazone is a well-known effective pesticide that is used for soybean crops. But at the same time, sulfentrazone is known for its high leaching potential through soil and could lead to ground water contamination Method: So we have synthesized a novel chitosan clay nanocomposites of sulfentrazone at three different concertations of sulfentrazone, 37.64%, 52.44% and 59.85% and its release pattern was studied at three different buffer systems like pH 2, pH 4 and pH 6. Release pattern of Sulfentrazone has been quantified by using High Performance Liquid Chromatography (HPLC) technique. Various mathematical tools have been applied to understand the release kinetics of chitosan clay sulfentrazone nanocomposites Result: Correlation coefficient (R2) of many models has been plotted and the Huguchi model was found to be the most suitable for these nanocomposites. The salient finding of this study is that the release rates of sulfentrazone at pH 4 is 68.39%, 42.62% and 37.75% after 8 hours at three different loading. This release pattern is higher than the release pattern at pH 6 and pH 2. Conclusion: Based on these release data, it is very clear that chitosan clay sulfentrazone nanocomposite can control the release of sulfentrazone at regular soil pH conditions, which is pH 6.

Preparation of Melamine Urea Formaldehyde Organo Clay Nanocomposite Foams Using Thermal Processing and Microwave Irradiation Techniques and Investigation of Their Thermal Insulation and Compressive Strength

Preparation of Melamine Urea Formaldehyde Organo Clay Nanocomposite Foams Using Thermal Processing and Microwave Irradiation Techniques and Investigation of Their Thermal Insulation and Compressive Strength

Correction to “A correlation between morphology and mechanical performance of injected‐molded PE/EVA/clay nanocomposites: Insight into phase miscibility and interfacial phenomena”

Correction to “A correlation between morphology and mechanical performance of injected‐molded <scp>PE</scp>/<scp>EVA</scp>/clay nanocomposites: Insight into phase miscibility and interfacial phenomena”

A comparative study of thermal and morphological properties of polyhydroxybutyrate/bentonite clay and polyhydroxybutyrate/organically modified nanoclay composites

AbstractBacterial biopolymers are polymeric materials that are produced by microorganisms. Due to its inherent brittleness and slow crystallization rate, it has limited industrial applications. Polyhydroxybutyrate (PHB) composites have been created to tackle these problems by combining non‐modified clay and organically modified nanoclay. In this study, 3 wt % of two different kinds of clays were incorporated to PHB through melt mixing method to prepare composites of PHB/bentonite Clay (BC) and PHB/organically modified nanoclay (Cloisite 30B (C30B)). The characteristics of PHB and its composites were investigated to study their thermal, rheological, morphological, surface properties and biodegradability. The study showed that the incorporation of C30B and BC into the PHB matrix improved the crystallization temperature to 97.30 and 96.82°C respectively as compared to the crystallization temperature of the PHB matrix as 88.79°C. The increased result of storage modulus (G') and loss modulus (G") in its rheological analysis confirmed that there was proper melt intercalation in case of both PHB/C30B and PHB/BC composite. The morphological characteristics results provide less coagulation and good clay distribution over the polymer matrix which leads to improved contact angle of 66.60° and 68.15° in case of PHB/BC and PHB/C30B respectively. Further both the composites and PHB film showed biodegradation characteristics. In the realm of nanocomposite films for various applications, where the cost is the major consideration, the PHB/BC composite films are promising economical solution in place of high cost PHB/C30B nanocomposite films.Highlights The BC/PHB and C30B/PHB composite films were developed using a micro‐compounder. Each films having a thickness 0.6 mm was extruded using a die. Uniform dispersion of clay is characterized from SEM. PHB with clay, boosted complex viscosity, storage, and loss modulus. PHB decomposes readily in compost, as do PHB/C30B and PHB/BC composites.

Simple and scalable preparation of lignin based porous carbon coated nano-clay composites and their efficient removal for the diversified iodine

Here, lignin and nano-clay were used to prepare novel composite adsorbents by one-step carbonization without adding activators for radioactive iodine capture. Specially, 1D nano-clay such as halloysite (Hal), palygorskite (Pal) and sepiolite (Sep) were selected as skeleton components, respectively, enzymatic hydrolysis lignin (EHL) as carbon source, lignin based porous carbon/nano-clay composites (ELC-X) were prepared through ultrasonic impregnation, freeze drying, and carbonization. Characterization results indicated lignin based porous carbon (ELC) well coated on the surface of nano-clay, and made its surface areas increase to 252 m2/g. These composites appeared the micro-mesoporous hierarchical structure, considerable N doping and good chemical stability. Results of adsorption experiments showed that the introduction of ELC could well promote iodine vapor uptake of nano-clay, and up to 435.0 mg/g. Meanwhile, the synergistic effect between lignin based carbon and nano-clay was very significant for the adsorption of iodine/n-hexane and iodine ions, their capacity were far exceed those of a single material, respectively. The relevant adsorption kinetic and thermodynamics, and mechanism of ELC-X composites were clarified. This work provided a class of low-cost and environmentally friendly adsorbents for radioactive iodine capture, and opened up ideas for the comprehensive utilization of waste lignin and natural clay minerals.

Effect of covalently functionalized Indian bentonite clay on thermal, mechanical strength and morphology structure of extrusion/injection‐molded nylon 6 composites

AbstractThe research and development of functional polymer composites and their production have posed significant challenges, particularly in creating high mechanical strength and thermal stability composites. In this study, we utilized a micro corotation extruder and injection molding to produce covalently functionalized Indian bentonite clay‐nylon 6 high‐strength nanocomposites. For comparison, two different amines, 3‐aminopropyl trimethoxysilane and N‐[3‐(trimethoxysilyl) propyl] ethylene di‐amine, were used to functionalize bentonite clay. Additionally, 3% and 5% less amino clay filler was added in the nanocomposite to manufacture the polymer composite. Analytical techniques such as Powder X‐Ray Diffraction, Fourier transform infrared, thermal gravimetric analysis, and Brunauer–Emmett–Teller surface area were used to characterize the molecular orientation of amine functionalization on clay minerals. Wide‐angle X‐ray diffraction, atomic force microscopy, and transmission electron microscope were used to characterize the nylon 6 intercalated in amino clay nanocomposite and the polymer structure morphology. Thermogravimetric analysis and differential scanning calorimetry were used to investigate the crystalline thermal behavior of clay‐nylon 6 composites. From the results, it was observed that the composition containing 5 wt.% amino clay demonstrated a significant improvement in tensile strength when compared with the composition containing 3 wt.% amino clay. The mechanical strength and the thermal behavior showed a significant improvement of ⁓200% for 5% amino clay‐nylon 6 nanocomposite.

Establishing the Link across the Synthesis Reaction Kinetics, Structural Changes, and Photocatalytic Efficiency of an Enhanced Chitosan–Clay (1:3) Nanocomposite

This research investigates the influence of synthesis kinetics on the structural and photocatalytic properties of chitosan–clay nanocomposites (Cs/MMT) and chitosan–hectorite nanocomposites (Cs/HET), employing an optimized initial stoichiometry of 1:3. Utilizing a variety of analytical techniques, including X-ray diffraction (XRD), transmission electron microscopy (TEM), and Fourier-transform infrared spectroscopy (FTIR), the study explores the structural evolution of the nanocomposites and their photocatalytic performance using semiconductor catalysts TiO2 and ZnO. The findings emphasize the significant impact of reaction kinetics, particularly after 3 h of reaction time, on the structural features of the nanocomposites. Notably, Cs/MMT demonstrates greater crystalline stability compared to Cs/HET due to variations in octahedral cavity occupancy in the initial clays. FTIR and TEM analyses depict the progressive evolution of the nanocomposites during the reaction, shedding light on how reaction kinetics drive the formation of specific bonds within the nanocomposites. In terms of photocatalytic activity, this study provides insights into the complex dynamics of photocatalytic degradation, with a specific focus on the performance of TiO2 and ZnO under diverse experimental conditions. The superior efficacy of TiO2 as a catalyst, particularly when integrated with Cs/MMT nanocomposites, is unequivocally demonstrated, with degradation rates exceeding 80%. This preference stems from TiO2 consistently exhibiting higher degradation rates compared to ZnO, attributed to structural disparities between montmorillonite and hectorite, influencing catalyst–support interactions. The findings underscore the critical importance of selecting suitable catalyst and support matrix combinations for optimizing performance in specific applications.

Covalently assembling multi-dimensional carbon-based nanoclay composites via ionic liquid linkers into PVA membrane for molecular separation

The application of membrane-based separation technology in purifying azeotropic solutions plays a crucial role in minimizing energy consumption during reactive distillation. The strategic integration of multi-dimensional structural composites within mixed matrix membranes (MMMs), characterized by a robust framework and efficient molecular transport channels, poses challenges but demonstrates significant potential for advancing the development of high-performance membrane fabrication. Herein, we proposed a novel strategy to covalently assemble halloysite nanotubes (HNTs) and graphene oxide (GO) using ionic liquids (ILs) as linkers. When incorporated into the polyvinyl alcohol (PVA) matrix, the ILs@HNTs@GO (IHGO) composites exhibit excellent interfacial compatibility, and ILs also enhanced the composite’s selective transfer ability to water molecules. The optimal separation performance for pervaporation dehydration from a ternary solution was respectively 2.57 (selectivity) and 1.74 (permeability) times higher than those of the pristine PVA membrane. The structural stability of the MMMs and their separation mechanism has been comprehensively validated by adjusting the content of GO in IHGO composites and conducting simulations. This study holds significant theoretical and practical implications for organic compounds purification, while simultaneously paving new avenues for the fabrication of structurally robust and high-performance MMMs with optimal filler effectiveness.

Study of vulcanization characteristic, mechanical, dynamic mechanical and thermal properties of silicone rubber, EPDM, and their hybrid clay nanocomposites

Study of vulcanization characteristic, mechanical, dynamic mechanical and thermal properties of silicone rubber, <scp>EPDM,</scp> and their hybrid clay nanocomposites

A novel strategy to prepare rubber/clay nanocomposites via compounding clay gel into cocoamidopropyl betaine modified styrene butadiene rubber

In this study, high performance styrene-butadiene rubber (SBR)/clay nanocomposites (NCs) modified by cocoamidopropyl betaine (CAPB) are prepared via an efficient and facile strategy. CAPB-modified SBR was compounded with clay gel via gel compounding method to obtain SBR/clay composites. The effect of processing condition and CAPB on the mechanical properties of the SBR/clay composites was investigated. XRD and TEM results show that clay dispersion in SBR matrix is significantly improved due to the success of CAPB in the hydrophilic modification of SBR. The clay-SBR interaction is enhanced and more SBR molecular chains are adsorbed to the clay, significantly improving the mechanical properties of SBR/CAPB/clay NCs, as demonstrated by SEM and DMA. The maximum tensile strength of SBR/CAPB/clay NCs achieved 16.3 MPa at a clay loading of 40 phr, which is 10 times that of pure SBR. The tensile strength of the SBR/CAPB/clay NC incorporated with 20 phr clay has exceeded that of the SBR composite incorporated with 40 phr commercial organic clay. This work demonstrates that this strategy, which combines the CAPB-modification of SBR with the gel compounding method, is an effective and feasible method to improve the mechanical strength of SBR.

Starch–Organo Layer Silicate Masterbatch Formulation in LLDPE–Starch–Clay Nanocomposite Processing: Changes in Transparency, Barrier, and Biodegradability

Starch–Organo Layer Silicate Masterbatch Formulation in LLDPE–Starch–Clay Nanocomposite Processing: Changes in Transparency, Barrier, and Biodegradability