Nanoclay Content Research Articles

Comprehensive Analysis of Wear, Friction, and Thermal Resistance in PVDF/Nanoclay Composites Using Taguchi Methodology for Enhanced Tribological Performance

This study discusses the tribological characteristics of Polyvinylidene Fluoride (PVDF)/nanoclay composites, focusing on the effects of nanoclay content (0, 1, 2 and 3 wt.%), load, sliding speed, and sliding distance on the wear rate, friction coefficient, specific wear rate, and temperature. A Taguchi Design of Experiments technique was applied to optimize and assess these aspects. The results demonstrated that nanoclay addition considerably improved the wear resistance and frictional stability of the PVDF composites. Specifically, a nanoclay concentration of 3 wt.% gave the lowest wear rate (0.05 mg/m) with a 10 N load and 100 m sliding distance, lowering wear by roughly 23% compared to unreinforced PVDF. The friction coefficient was similarly lowered by 12% with 3 wt.% nanoclay, reaching a value of 0.38 at the highest load of 40 N. Interaction effects demonstrate that load and sliding distance are key elements impacting wear performance, with large loads and long distances virtually tripling the wear rate. ANOVA results quantify nanoclay’s contribution to a wear rate reduction of 51.29%, whereas load and sliding distance contributed 22.47% and 16.98%, respectively. Temperature increases due to frictional heating reached 10 °C under rigorous test conditions, although nanoclay treatment decreased this increase by an average of 15%. Characterization by XRD and FTIR verified the nanoclay dispersion inside the PVDF matrix, whereas the SEM images demonstrated smoother surfaces and fewer wear tracks in the nanoclay-reinforced samples. These findings illustrate the efficiency of nanoclay in increasing the wear resistance of PVDF, making these composites appropriate for high-performance applications. This research provides useful insights into enhancing PVDF/nanoclay composites, with possible uses in situations that demand endurance and thermal stability.

Microstructure development and dynamic-mechanical properties of polybutadiene rubber/nanoclay: Effect of curing system

This study investigates the fabrication and characterization of polybutadiene rubber (BR) nanocomposites incorporating organoclay (OC) through melt mixing with a focus on the microstructure development and properties of the cured materials using sulfur curing and electron beam irradiation. The role of epoxidized natural rubber (ENR50) as a compatibilizer to improve interfacial interactions is explored. X-ray diffractometer (XRD) and scanning electron microscopy (SEM) analyses confirm the intercalation structure of clay nanoplates within the nanocomposites. Mechanical properties measurements highlight the enhancement of tensile strength and elongation at break with increasing nanoclay content in sulfur-cured nanocomposites while in the case of the irradiated samples the tensile strength increased as the nanoclay content increased from 3 to 7 wt% up to a dose of 150 kGy after which it decreased with further dose increments and exhibit a dose-dependent behavior. Dynamic Mechanical Analysis (DMA) reveals a strong chain-nanoparticle interaction with irradiated samples at 150 kGy displaying superior storage modulus and reduced loss factor compared to sulfur-cured counterparts. Furthermore, the incorporation of ENR50 as a compatibilizer proved beneficial in enhancing the interaction between the BR chains and the modified nanoclay. These findings offer valuable insights into the design and performance of rubber nanocomposites for advanced applications.

Evaluating the properties of starch/chitosan films with the incorporation of various nanoclays for use in food packaging.

This study evaluates the properties of starch/chitosan films (SCF) produced via the casting method, incorporating 40% (w/w) plasticizers (glycerol and sorbitol) and various concentrations (0, 3, 5, and 10% (w/w)) of nanoclays (Cloisite 20A, Cloisite 30B, and K-10). The effects of each nanofiller on the films were thoroughly investigated. Films containing nanoclays exhibited reduced water solubility and enhanced thermal stability compared to films without nanofillers. A higher nanoclay concentration (10% (w/w)) led to a reduction in the solubility of the starch/chitosan films, with a decrease of approximately 15% relative to the SCF sample. Incorporating the three types of nanoclays improved tensile strength at break, particularly in samples with 3% and 5% (w/w) nanoclay content, achieving an approximate 68% increase in tensile strength at break compared to the SCF sample. Atomic Force Microscopy (AFM) analysis revealed that increasing nanofiller content significantly heightened surface roughness. Films incorporating Cloisite 30B demonstrated lower surface roughness than those with Cloisite 20A and K-10 nanoclays, especially at concentrations of 3% and 5% (w/w), with a reduction of approximately 40%. X-ray diffraction (XRD) analysis indicated superior interaction in films containing Cloisite 20A and 30B, while films with 10% (w/w) K-10 exhibited a diffraction peak at 8.88°, suggesting inadequate incorporation. These findings align with the AFM analysis results for this film. Consequently, the integration of nanoclays improves the properties of starch/chitosan films, with formulations utilizing 20A and 30B nanoclays at 3% and 5% (w/w) showing the most promising potential for future applications in food packaging.

Experimental evaluation of nanoclay assisted water based EOR method

Recently, one of the most applicable nanoparticles (NPs) is nanoclay that is especially used in drilling to enhance the rheology of the drilling fluids. However, the experimental analysis of nanoclay in enhanced oil recovery (EOR) applications was rarely investigated. The main goal of this study is to find an ideal nanoclay concentration for the EOR fluid in two steps. The first is nanoclay stability that focus on finding the most stable nanofluid and the second is interfacial tension (IFT) and contact angle (CA) measurement that concentrate on selecting the best EOR fluid. Experiments such as nanofluid preparation, nanofluid stability, Dynamic Light Scattering (DLS), Zeta potential, X-Ray Diffraction (XRD) and Scanning Electron Microscope (SEM) analysis, clay swelling tests, CA and IFT measurements were performed for this purpose. All of the experiments were done in ambient pressure and temperature. The core samples and thin sections that are used in the experiments are oil-wet in nature. Results of the experiments confirm the stability of nanoclay in presence of the selected surfactant Cetyl Trimethyl Ammonium Bromide (CTAB) employed in the study. On the other hand, nanoclay has the ability to reduce the IFT nearly 5 dyne/cm, and also the combination of nanoclay and CTAB modify CA in the order of 10. It is founded that the optimum concentration for EOR fluid during the experiments is 0.5 weight% (wt%) CTAB and 0.1 wt% nanoclay.

Investigation of the Brittleness and Sensitivity of the Gypseous Sand Improved by Nano-clay

This study examines the brittleness index and sensitivity ratio of two gypseous sand soils under saturation conditions improved by nano-clay. The soil samples were obtained from the cities of Al-Najaf and Tikrit containing 29% and 55% gypsum, respectively. The tests were performed on remolded specimens in a direct shear box. The soil specimens were examined mainly under saturated conditions for both different soil and nano-clay contents (0, 2, 5, and 7 %) under three normal stress levels: 25, 50, and 100 kPa. Additional tests were performed under dry soil conditions for comparison. The calculations of the brittleness index and sensitivity ratio of the saturated soil specimens were dependent on the newly suggested definitions of the peak values of the shear stress. The tP is the peak value in the dry condition, whereas the tR is the peak value in the saturation condition. The results emphasize that the values of the brittleness index and sensitivity ratio require more attention to the possibility that the soil is brittle owing to increased gypsum dissolution and the demolition of the soil structure. The brittleness index and sensitivity ratio increased with increasing gypsum content and decreased with increasing nano-clay content and average stress levels. The optimum percentage of nano-clay for both soil specimens was found to be 5%.

Physico-mechanical Properties of Nano Bio-films For Application in Food Packaging

Petroleum-based packaging has long dominated the packaging industry, raising environmental concerns. As a result, the packaging industry has started using nano bio-plastics. Incorporating nanoparticles, nano bio-plastic packaging helps in prolonging product shelf life. Additionally, packaging manufactured of nano bio-plastic is made of biodegradable polymers. Nano bio-films made from polylactic acid (PLA) and nanoclay were produced using a solvent casting process. 1.0%, 3.0% and 5.0% (wt.) of nanoclay were added to the PLA solution. The mechanical, chemical, morphological and transparency properties of nano bio-films were investigated. To improve their suitability for food packaging applications, tensile test, Fourier-transform Infrared Spectroscopy (FTIR), scanning electron microscopy (SEM) and UV-barrier test were performed. With tensile strength (TS) of 30.36 MPa and elongation at break (EAB) of 7.05%, respectively, nano bio-films with 3.0 wt. % nanoclay demonstrated higher mechanical properties than pure PLA film with about 35% of increment. In aspects of FTIR analysis, no significant differences were found with both nano bio-films and pure PLA film. The SEM morphology shows that adding nanoclay at 3.0 wt. % improves the adhesion between the PLA matrix and the nanoclay. The addition of nanoclay had a minimal impact on the PLA film's transparency, and it was interesting to see that nanoclay concentration of 1.0 wt. % and 3.0 wt. % had roughly the same light transmission values of 84.86% and 83.95%, respectively. According to the findings of this study, the PLA nano bio-film with 3.0 wt% nanoclay exhibits the optimum physico-mechanical properties.

High Self‐Supporting Chitosan‐Based Hydrogel Ink for In Situ 3D Printed Diabetic Wound Dressing

AbstractCustomizable 3D‐printed biopolymer hydrogels, highly sought after for diabetic wound management, face challenges in clinical application due to weak physical crosslinking within their constituent inks. In this study, a novel chitosan‐based hydrogel ink with a dense yet reversible physical crosslinking network is subtly designed for the rapid in situ fabrication of personalized diabetic wound dressing. This robust network is established through multiple electrostatic and hydrogen bonding interactions between unique carboxymethyl chitosan and nanoclay, further reinforced by the introduction of amide bonds, which act as double hydrogen bond donors/acceptors. Benefiting from this network, the ink with low nanoclay content exhibits remarkable self‐supporting properties, enabling high‐fidelity, large‐scale, and complex 3D printability without additional processing, while substantially retaining its inherent rheological properties after autoclave sterilization and the incorporation of active components. Given these advantages, this multifunctional 3D printable hydrogel can be rapidly in situ constructed on diabetic wounds. Simultaneously, the 3D‐printed hydrogel demonstrates biodegradability, anti‐swelling, and appropriate mechanical properties, along with remarkable in vitro antibacterial and pro‐angiogenic capabilities, leading to effective diabetic wound healing in vivo. This work offers a new strategy for creating highly self‐supporting biopolymer inks and paves the way for developing advanced personalized wound dressings.

Production of Defragmentable Bioplastic using Starch Extracted from Annona Muricata (Soursoup) Seed Reinforced with Bentonite Nanoclay

Abstract Seeds of Annona Muricata, often called soursop or guyabano were used as a source of starch for the production of defragmentable bioplastic. The researchers used mixture of water and starch content of 10 and 20 grams respectively from Annona Muricata (soursop) seeds with various concentration (20%, 25%, 30%) of glycerol (plasticizer) and reinforced with three different concentrations (0%, 3%, 6%) of bentonite nanoclay (filler). The characterization of the bioplastic was carried out by determining the effect of variation of the ratio between the quantity of starch from soursop seeds, bentonite nanoclay, and glycerol. The starch-based defragmentable bioplastic was evaluated with its water retention, degradation, and mechanical properties. The result showed that the tensile strength improved significantly with the addition of bentonite nanoclay and the elongation at break with the addition of glycerol. Same way in water retention test, where the presence of the bentonite nanoclay increased the strength of the bioplastic with its water solubility. In soil burial test, a higher level of glycerol concentration increased the rate of the bioplastic degradation. By adding the bentonite nanoclay as a filler, the rate of bioplastic degradation decreased compared to the bioplastic without filler. In shelf-life test, adding glycerol as plasticizer improved the shelf life of bioplastics. A high concentration of glycerol served as an anti-fungal for bioplastics.

Mechanical Performance on Flax Fibre Epoxy Composites Filled with Montmorillonite Nanoclay for Lightweight Applications

The objective of this study is to investigate the mechanical performance on develop flax/epoxy composite filled with montmorillonite nanoclay for lightweight applications. For this purpose, firstly, nanoclay at different weight percentages montmorillonite nanoclay such as 0.5, 1, 1.5 was dispersed homogeneously into epoxy resin with the help of ultrasanitization process. For better nanoclay distribution in composite, the montmorillonite nanoclay concentration higher than 1.5% was not analyzed. Secondly, using this mixture, flax fiber based composites were produced by vacuum bag molding process. Finally, the mechanical properties of flax/epoxy composites filled with different percentages montmorillonite nanoclay were determined with tensile, flexural, and in-plane shear test. From the experimental results obtained, the addition of montmorillonite nanoclay indicate positive effect on the performance of the composites compared with the neat composite samples, if the montmorillonite nanoclay distribute homogeneously in the epoxy. The composites added with 0.5 wt.% nanoclay showed the highest tensile modulus and tensile strength. Moreever, the elasticity modulus of composite samples with 0.5% nanoclay addition is approximately 87% higher than the pure composite. Also, the composite samples loaded with 1.5 wt.% of montmorillonite nanoclay performs better under flexural loading conditions.

Development of cement slurries with additives of nanoclay particles for the construction of oil wells at elevated temperatures

Relevance. Strength decrease is a phenomenon that becomes more pronounced as the temperature rises above 110°C. It is characterized by significant chemical and microstructural changes that Portland cement undergoes at high temperatures. Adding silica particles (SiO2) to cement can significantly increase cement resistance to strength reduction when the temperature exceeds 110°C. Nanoclays are currently used in the cement industry to increase the strength of the cement matrix due to their ability to fill capillary micropores and due to their relatively small particle size. Aim. To investigate the effect of adding nanoparticles (nanoclay) to Saudi grade G cement on compressive and tensile strength, and cement stone permeability under high temperature conditions (300°С). Objects. Six samples of cement mortars with different concentrations of nanoclay, cement stones from, tested after 7 and 28 days of hardening at 25 and 300°C. Methods. Cement chemical composition was evaluated by the X-ray fluorescence method with the WORKSTN-V Olympus Vanta X-ray fluorescence analyzer. Cement physical composition was evaluated by the method of ray diffraction on the Mastersizer 2000 laser particle size analyzer. The test of the grouting stone samples was carried out in accordance with ISO 10426-2:2003 on a hydraulic press 65-L1132. The tensile strength of the samples by the Brazilian method was tested in accordance with ASTM D 3967-08 standard on a hydraulic press 65-L1132. The permeability of the samples was determined by single-phase stationary filtration at a facility for studying the filtration and capacitance properties of the PIK-OFP-UCH core in accordance with ISO 10426-2:2003. Results. The data obtained showed that cement destruction at extremely high temperatures can be avoided by using nanoclay (up to 3% by weight of cement). The microstructure of the cement matrix was significantly affected due to the aggregation of nanoparticles when more than 3% of nanoclay was added. All rheological characteristics of the cement slurry were improved by the addition of nanoclay particles.

Assessing the Fatigue Stress Behavior of Starch Biodegradable Films with Nanoclay Using Accelerated Survival Test Methods

A destructive degradation model was applied on films made from different concentrations of starch, glycerol and nanoclay using various elongation levels as a stress variable at different stress times and stretch cycles. The log tensile quotient (logarithm of the tensile strength to the corresponding break cycle) was recorded as the response variable. The log tensile quotient increased, and the log exact break time decreased, as the elongation level increased. The treatment containing the highest starch and nanoclay and lowest glycerol content proved to be the most resistant to stress conditions and the most versatile in relation to the varying log tensile quotients, while the treatments containing the lowest nanoclay and highest glycerol contents, regardless of the starch concentration, manifested the lowest log tensile quotient at higher levels of log exact break time. According to multiple regression findings, the break cycle governed mostly the stress conditions in the degradation model, followed by the sample ID and the log exact break time. The term log tensile quotient, attempted for the first time on data concerning biodegradable films enhanced with nanoclay, seems very promising for deeper research due to its ability to retrieve predictive information from survival equations and to discriminate the difference between film structures.

Toward 3D printability prediction for thermoplastic polymer nanocomposites: Insights from extrusion printing of PLA-based systems

The development of new thermoplastic-based nanocomposites for, as well as using, 3D printing requires extensive experimental testing. One typically goes through many failed, or otherwise sub-optimal, iterations before finding acceptable solutions (e.g. compositions, 3D printing parameters). It is desirable to reduce the number of such iterations as well as exclude failed experiments that often require laborious disassembly and cleaning of the 3D printer. This issue could be addressed if we were able to understand, and ultimately predict ahead of experiments if a given material can be 3D printed successfully. Herein, we report on our investigations into forecasting the printing and resultant properties of polymer nanocomposites while encompassing both material properties and printing parameters, enabling the model to generalize across various thermoplastics and additives. To do so, nanocomposites of two different commercially available bio-based PLAs with varying concentrations of nanoclay (NC) and graphene nanoplatelets (GNP) were prepared using a twin-screw extruder. The thermal and rheological properties of the nanocomposites were analyzed. These materials were printed at varying temperature and flow using a pellet printer. The quality of the printing was evaluated by measuring weight fluctuation, internal diameter of cylindrical specimen, and surface uniformity. The interactions between material properties and printing parameters are complex but captured effectively by a machine learning model, specifically we demonstrate such a predictive model to forecast printability and, printing quality utilizing a Random Forest algorithm. Printability was predicted by developing a classification model with constraints based on the weight fluctuation (ΔW) of the printed sample w.r.t. the optimal print; defining “not printable” for −1.0≤ΔW<−0.8 and “printable” for ΔW≥−0.8. The classification model for predicting printability, performed well with an accuracy of 92.8% and identified flow index and complex viscosity, contributing 52% to the model’s importance. Another model to predict ΔW of the only on successful prints also showed strong performance, emphasizing the importance of viscoelastic properties, thermal stability, and printing temperature. For diameter change (ΔDi), the Random Forest model identified flow consistency index, complex viscosity, and thermal stability as influential parameters, with crystallization enthalpy gaining increased importance, reflecting its role in crystallization and shrinkage. In contrast, the surface roughness average (RA) model had lower performance, yet revealed remarkable insights regarding the feature importance with crystallization enthalpy and complex viscosity being most significant.

Prediction of Mechanical Properties of Nano-Clay-Based Biopolymeric Composites.

An understanding of the mechanical behavior of polymeric materials is crucial for making advancements in the applications and efficiency of nanocomposites, and encompasses their service life, load resistance, and overall reliability. The present study focused on the prediction of the mechanical behavior of biopolymeric nanocomposites with nano-clays as the nanoadditives, using a new modeling and simulation method based on Comsol Multiphysics software 6.1. This modeling considered the complex case of flake-shaped nano-clay additives that could form aggregates along the polymeric matrix, varying the nanoadditive thickness, and consequently affecting the resulting mechanical properties of the polymeric nanocomposite. The polymeric matrix investigated was biopolyamide 11 (BIOPA11). Several BIOPA11 samples reinforced with three different contents of nano-clays (0, 3, and 10 wt%), and with three different nano-clay dispersion grades (employing three different extrusion screw configurations) were obtained by the compounding extrusion process. The mechanical behavior of these samples was studied by the experimental tensile test. The experimental results indicate an enhancement of Young's modulus as the nano-clay content was increased from 0 to 10 wt% for the same dispersion grades. In addition, the Young's modulus value increased when the dispersion rate of the nano-clays was improved, showing the highest increase of around 93% for the nanocomposite with 10 wt% nano-clay. A comparison of the modeled mechanical properties and the experimental measurements values was performed to validate the modeling results. The simulated results fit well with the experimental values of Young's modulus.

Improving flame resistance and shielding properties for cross-linked polyethylene (XLPE) using nanoclay filler

Polymers play an essential role in both industry and medical fields due to their diverse and adaptable properties. In this work, prepared crosslinking polyethylene (XLPE) samples with hydrophilic bentonite nanoclay fillers (H2Al2O6Si) at concentrations of 0, 1, 2.5, 4, and 5 wt% enhance their flame-retardant and radiation shielding efficiency. The research investigated flame retardancy and thermal stability parameters. The XLPE/H2Al2O6Si nanocomposite polymer sheets were exposed to a collimated beam of fast neutrons using an Am/Be neutron source (5 Ci) and to gamma radiation using a 137Cs point source (5 μCi) to assess their radiation shielding properties. The study found that uniform dispersion of nanoclay particles enhanced the thermal properties of the composite, forming a char layer that acted as a barrier, slowing thermal decomposition and reducing the heat release rate. Limiting oxygen index (LOI) increased from 28% to 34%, and burning rate improved with higher nanoclay concentrations. Additionally, absorption and optical band gap calculations decreased with increasing filler concentrations. Radiation attenuation capabilities increased by approximately 40% for neutrons and 30% for gamma radiation compared to pure XLPE. The study concluded that incorporating nanoclay fillers into XLPE enhances its shielding capabilities and improves flame resistance properties, making the prepared samples suitable for various industrial applications.

Improving the compatibility of polylactic acid/polycarbonate blends with nanoclay and Joncryl as chain extenders

AbstractThis study aimed to optimize the compatibility and performance of PLA/PC blends by investigating the effects of Cloisite 20A nanoclay (NC) and Joncryl chain extender (CE). PLA/PC blends with varying NC and CE loadings were prepared, and the optimal formulation was identified. The optimal NC and CE content were then used to produce PLA/PC blends with varying PC ratios. The test specimens were produced by mixing the mixture in a twin‐screw micro compounder and subsequent injection molding into dog bone specimens to investigate the thermal, mechanical, and morphological properties of the blends. Scanning electron microscopy and dynamic mechanical analysis confirmed the immiscibility of the unmodified blend, but significant improvements in blend morphology were observed with high NC/CE ratios. The presence of NC/CE resulted in reduced droplet size of dispersed PC phase and a new intermediate glass transition temperature (Tg) in DMA, suggesting partial miscibility. The highest thermal stability improvement was achieved with 5 wt% NC alone or a combination of 5 wt% NC and 1 wt% CE. Composites containing NC/CE showed the most significant improvements in composite properties, demonstrating their effectiveness as compatibilizers and improved compatibility in PLA/PC blends. These results indicate that the use of NC/CE is a promising method for expanding the applicability of PLA/PC blends.

Mechanical behavior of GFRP-Polymer sandwich composites with montmorillonite nanoclay

Abstract A sandwich composite consists of high stiffness and high strength outer layers called face sheets and low-density inner layers called core. In the present study, the sandwich composites comprising glass fabric/epoxy face sheets and epoxy modified with montmorillonite (MMT) nanoclay core are fabricated by a co-curing method. The sandwich panels show higher static tensile and three-point flexural properties such as ultimate strength, elastic modulus, and failure strain on adding up to 3 wt.% of MMT nanoclay contents than pristine sample. The former properties reduce at 4 and 5 wt.% of nanoclay contents owing to the formation of clustering of clay particles within the matrix. The stress-strain behavior of sandwich panels with 0–5 wt.% of MMT nanoclays obtained by laminated plate model follows experiments. The maximum lateral deflection of sandwich panels with nanoclays predicted by assuming them to be a simply supported beam is in-line with experimental results. For low-velocity single impact perforation load, the maximum force of sandwich panels improves on the infusion of up to 3 wt.% of clay while maximum displacement decreases. The ballistic limit velocity and energy absorption of panels improve on adding up to 3 wt.% of clay. Beyond the ballistic limit at different initial velocities, the residual velocity of sandwich panels decreases on addition of up to 3 wt.% of clay and energy absorption increases.

The nano-clay effect on the improvement of the thermal, flammability, and mechanical behavior of epoxy/glass fiber/ATH hybrid composites

More than 50% of the flame retardants used in the polymer and plastic industries are metal hydroxides. Among them, aluminum trihydroxide (ATH) is the most widely used due to its low toxicity and corrosiveness and its cost-effectiveness. The use of high-volume ATH in polymers reduces the mechanical properties. In this work, clay nanoparticles were added into epoxy/glass fiber/ATH hybrid composites to improve the mechanical and thermal properties of the composites. The effect of nano-clay content (1, 3, and 5 phr) on mechanical properties such as tensile and flexural strength and modulus, and thermal properties was investigated. Thermal properties were evaluated by Differential Scanning Calorimetry (DSC), and Thermogravimetric Analysis (TGA). The result of mechanical tests showed that adding 3 phr of clay nanoparticles increases tensile and flexural strength by 10% and 9.2%, respectively. The flammability of the composites was measured in horizontal mode. The flammability results revealed that introducing 3 phr of nano-clay improves the flammability of the composites by 41%.

Tribological behavior of epoxy/nano-clay nanocomposites used as a floor coating

Floor coating is a contemporary technique used to substitute traditional flooring materials like ceramic, oak, and alabaster with epoxy paint. The properties of epoxy floor coatings were studied in terms of mechanical properties, wear resistance, and tribological properties. Nano-clays (MMT for epoxy) were added for reinforcement in different proportions (0, 0.5, 1, 2, and 4 wt.%) using the ultrasound dispersing device. The results show that the wear resistance of the nanocomposite coating reinforced with 2% nanoclay is improved by 82% compared to pure epoxy. The hardness increases by about 13.8% and 19.7% when the nanoclay content is 0.5% and 4%, respectively, compared to pure epoxy, while the adhesive strength decreases with increasing the weight percentage of nanoclay in the composites. In addition, results show that scratch hardness improved by 37.5% and 118.75% when nanoclay content was 0.5% and 4%, respectively.

The Effect of Nanoclay Type on the Mechanical Properties and Antibacterial Activity of Chitosan/PVA Nanocomposite Films

Nanoclays are a class of nanomaterials extensively used to prepare polymer nanocomposites. In this study, four types of common nanoclays were selected to prepare chitosan–polyvinyl alcohol (CP) nanocomposite films. Montmorillonite cloisite Na+ (MMT), organically modified montmorillonite (OMMT), and bentonite (BNT), as layered aluminosilicates, and halloysite nanotubes (HNT), as a tubular nanoclay, were blended with CP films at concentrations of 1.5, 3 and 4.5%. The nanocomposite films were characterized by FTIR, XRD, SEM/EDX, AFM, tensile strength, and antibacterial tests. SEM/EDX results showed a more uniform distribution of the OMMT and HNT nanoclays in the polymer matrix. AFM images showed a rougher surface for nanocomposite films compared to CP film. Increasing the nanoclay concentration in the films from 1.5 to 4.5% resulted in higher tensile strength for HNT and MMT while the trend was reversed for OMMT and BNT. Among the samples, nanocomposite films composed of OMMT and BNT showed the highest tensile strength at the lowest concentrations (CP-OMMT1.5 99 ± 3.7 MPa, CP-B1.5 81 ± 1.5 MPa). The nanocomposite films prepared from OMMT showed the highest antibacterial activity against E. coli and S. aureus with an inhibition zone of 15 and 19 mm, respectively. The results of this study showed that BNT and OMMT are promising nanoclays for enhancing the mechanical properties and antibacterial activity of hydrophilic polymers. The results of this research can provide new insights into selecting suitable nanoclays for different applications.

Functional Technical Textile-Based Polymer Nanocomposites with Adsorbent Properties of Toxins and Dyes also Have Antibacterial Behavior.

This is the first study of non-woven fabrics elaborated by melt-blowing from polymer nanocomposites made of Nylon 6 and nanoclay (Cloisite 20A) modified with an amine (1,4 diaminobutane dihydrochloride). Morphological and physical characteristics, adsorption capacity, and antibacterial properties are presented. From the X-ray diffraction (XRD) results, it was possible to observe a displacement of the signals to other 2θ angles, due to an α to ϒ phase shift. The scanning electron microscopy (SEM) images showed that the mean diameter of fiber decreased as the content of nanoclay increased. The mechanical tests showed that the tear strength force of neat nylon was 1.734 N, but this characteristic increased to 2.135 N for the sample with 0.5% modified nanoclay. The inulin adsorption efficiency of the Nylon 6/C20A 1.5% and Nylon 6/C20A 2% samples at 15 min was 75 and 74%, respectively. The adsorption capacity of Nylon 6/C20A 1.5% and Nylon 6/C20A 2% for methylene blue and methyl orange remained above 90% even after four adsorption cycles. In addition, non-woven fabrics present antibacterial activity against E. coli.