Cloisite 20A Research Articles

Effect of pre‐mastication on dispersion of nanoclay in presence of carbon black in an inner liner compound: Studies on physicomechanical and functional properties

AbstractThe present study demonstrates the use of “pre‐mastication” technique for getting higher dispersion of organoclay, Cloisite 15A, in an inner liner compound based on 70:30 bromobutyl and natural rubber blend, in presence of higher concentration of carbon black (60 phr) for the improvement of functional properties like fatigue cut growth and air permeability resistance. Studies have showed that the organoclay was almost equally distributed within the blend both in absence as well as in presence of carbon black. The vulcanization curve showed a marked increase in cure acceleration as well as a significant rise in the maximum torque value because of higher crosslinking aided by the participation of the quaternary amine present in Cloisite 15A; however, in the carbon black loaded compound, the cure acceleration was not so pronounced because of engaging interaction between amine and functional groups of carbon black. The microscopic study revealed a good dispersion of Cloisite 15A within the elastomer blend‐ in presence of carbon black. The anisotropic platelets of Cloisite 15A and carbon black particles jointly formed “nano units”, which occluded a portion of elastomer segments vis‐a‐vis partial intercalation within the clay gallery. Such a reinforcing model was instrumental in improving the physicomechanical and functional properties under static and dynamic conditions. The organoclay displayed a much‐improved properties at 2 and 4 phr doses in presence of 60 phr carbon black because of formation of enough “nano units” while deterioration was observed at 6 phr dose due to clay aggregation. Based on the results obtained on functional properties it was concluded that the 4 phr of organoclay compounded in “pre‐mastication” mode delivered the best improvement and thus it was recommended for future up‐scaling study.

Influence of the Nanoclay Concentration and Oil Viscosity on the Rheological and Tribological Properties of Nanoclay-Based Ecolubricants

This manuscript describes a rheological and tribological study carried out on eco-friendly lubricants. These ecolubricants were made up of nanoclays as dispersed phase (a layered nanosilicate (montmorillonite Cloisite 15A) and a fiber-like nanoclay (sepiolite Pangel B20)) and vegetable-based oil as continuous phase (castor oil (CO), high oleic sunflower oil (HOSO) and their mixtures). A series of nanoclay-based ecolubricants were prepared by varying both nanoclay concentration and base oil, and thus, its viscosity. Friction and wear behaviors were assessed by using a ball-on-three plates tribometer cell. The results showed that the fiber-like sepiolite Pangel B20 yielded an important reduction in the wear scar diameter, thus revealing its potential as anti-wear and load-carrying additive in ecolubricant formulations, while Cloisite 15A proved to have friction improving properties. These anti-wear and friction reducing properties were found to be influenced by both nanoclay concentration and oil viscosity.

Review: The Comparison of Clay Modifier (Cloisite Types) in Various Epoxy-Clay Nanocomposite Synthesis Methods

Nanocomposites are a new material discovery in the 21st century. One of the nanocomposite materials which are useful in life is epoxy-clay nanocomposites. Epoxy clay nanocomposites have a reasonably wide application in industrial fields such as aerospace, defense, automobile, etc. The purpose of writing this review is to conduct a literature review on mechanical properties in various Cloisite as a filler of Epoxy-clay Nanocomposites. There are several examples of cloisite, namely Cloisite 10A, Cloisite 15A, Cloisite 20A, Cloisite 25A, Cloisite 30B, and Cloisite 93A. Cloisite has the advantage of producing mechanical properties, especially in the tensile modulus and strength, which is more increased than conventional reinforcing materials. These methods' synthesis results were then characterized using TEM, SEM, XRD, and other tests to determine their mechanical properties. The material parameters resulting from nanocomposites' synthesis are well seen from the high Tensile strength and modulus values. The highest increase in mechanical properties was found in the cloisite 93A by the ultrasonic synthesis method or mechanical stirring based on the study results.

A study on coating with nanoclay on the production of flame retardant cotton fabrics

In this study, flame retardant properties of 100% cotton fabrics were tried to be improved by using commercial nanoclay (Cloisite 20A) which is a clay based montmorillonite. Flame retardancy and thermal decomposition behavior of the samples were characterized by the vertical burning test, limiting oxygen index (LOI), and thermogravimetric analysis (TGA). The surface morphology of untreated and treated fabric was examined using a scanning electron microscope (SEM). Fourier-transform infrared spectroscopy (FTIR) analysis was carried out for Cloisite 20A, untreated and coated fabrics. The results of the tests showed that the coating treatment even at low nanoclay concentration is enough to have a considerable flame retardant effect. This result was attributed to the barrier effect of the nanoclay.

Pillared cloisite 15A as an enhancement filler in polysulfone mixed matrix membranes for CO2/N2 and O2/N2 gas separation

The Cloisite 15A (C‒15A), an organically modified montmorillonite clay, was further modified with iron (Fe) pillars. Mixed matrix membranes (MMMs) were fabricated by incorporating Fe pillared Cloisite 15A (P–C15A) at different loading percentage of 0.1–1.5 wt% within the polysulfone (PSf) matrix. Fabricated membranes were characterized using thermal studies (TGA and DSC) and scanning electron microscopy (SEM). The morphological studies of fabricated MMMs confirmed that the P–C15A was well embedded through the PSf matrix. To investigate the effect of P–C15A incorporation, MMMs were tested for their gas permeation behavior using pure CO2, N2, and O2 gases. The gas permeation of MMMs was increased with the increase in loading percentage of P–C15A, whereas the gas selectivity was maintained at par to that of neat PSf membrane until it diminished at 1.5 wt% percentage of P–C15A causing mineral agglomeration. PSf/P–C15A (1 wt%) MMMs exhibited 232% and 274% increase in CO2 and O2 gas permeability respectively, while showing minimal variation in the selectivity of O2/N2 and CO2/N2 compared to that of neat PSf membrane. Furthermore, the gas separation performance of neat and P–C15A incorporated MMMs were compared with the Robeson upper bound. The PSf/P–C15A (1 wt%) MMM shown to have CO2 permeability of 18.01 barrer with the CO2/N2 and O2/N2 gas pair selectivities of 4.95 and 18.34 respectively, which depicted closeness towards the Robeson upper bound.

Diffusion and cure kinetic of sonicated nanoclay-reinforced unsaturated polyester resin

The influence of applying ultrasonic waves on cure kinetic parameters of unsaturated polyester resin (UP) reinforced with Cloisite 10A nanoparticles (10A) via non-isothermal differential scanning calorimetry has been studied. Advanced integral isoconversional method was used to study the influence of sonication on activation energy, pre-exponential factor and reaction model in terms of conversion degree. Furthermore, the kinetic parameters of Vyazovkin and Sbirrazzuoli diffusion factor (VS diffusion factor) and Kamal equations were obtained. The results proved that by applying ultrasound the dominance of the diffusion phenomenon shifted to lower conversion degrees. XRD and TEM tests were performed on samples containing nanoclay before and after the application of ultrasonic waves. The results showed that the application of ultrasonic waves had no significant effect on the intercalation and exfoliation of nanoclay platelets. Ultrasound breaks down agglomerates and thus more styrene adsorbs by nanoclay platelets. It was observed that in the final stage of the cure reaction, the sonication has a great effect on the activation energy and reduces it dramatically. Finally, the influence of sonication on optimal cure cycle of thin composite parts was investigated. The results showed that the application of ultrasonic waves increased the crosslinking reaction rate of the unsaturated polyester resin and decreased the optimum cure cycle time.

Formulating low cost modified bentonite with natural binders to remove pesticides in a pilot water filter system

A low cost bentonite was modified with Fe3+ and hexadecyltrimethylammonium (HDTMA) cations and subsequently optimized to be used in small-scale water filter systems. Two types of formulations were assessed: immobilization of modified clays on anthracite particles and their extrusion as pellets using the natural binders, colophony resin and carnauba and bee waxes. The innovation of this work was to assess which clay formulation showed better performance for the adsorption of the pesticides MCPA, tebuconazole and terbuthylazine in a pilot or pre-commercial water filter system. A commercial organoclay (Cloisite 10A®) and activated carbon were also assayed for comparison purposes. The characterization studies showed that the disintegration in water of the formulated clay adsorbents behaved better when formulated with carnauba wax as binder. The adsorption study was performed in a semi-pilot system by treating 40 L of contaminated water with pesticides in a closed circuit for 24 h at 0.8 bar where the formulated clays were placed in a fixed bed configuration with anthracite particles. Pesticide removal varied depending on the type of formulation, the highest removal efficiency (90–100 %) was reached for the immobilized HDTMA-clay on anthracite particles, which showed better pore distribution according to scanning electron microscopy. The values were similar to those rendered by the commercial Cloisite10A® and activated carbon. The outcomes from this work suggested the convenience of using the new formulated adsorbents based on low-cost raw materials in water purification systems, which may open economic possibilities and employment opportunities for rural areas.

Investigating microbial properties of traditional Iranian white cheese packed in active LDPE films incorporating metallic and organoclay nanoparticles

Iranian white Cheese is a traditional type of cheese in Iran which is popular and widely consumed because of its pleasant organoleptic properties. To manufacture this cheese, raw milk is heated below pasteurization temperature, therefore, pathogenic and spoilage bacteria remain and cause several diseases in public health. In this research three kinds of nanocomposite films based on LDPE incorporated 1) Ag, CuO, ZnO, 2) Cloisite 15A, Cloisite 20A, Cloisite 30B that produced by extrusion method were used for packaging of the cheese and kept in 4°C during 28 days. Data analysis carried out using SPSS statistical software based on a completely randomized design. The results showed the nanocomposite films incorporated with metal nanoparticles had a significant decrease in the growth of Staphylococcus aureus, coliform, mold and yeast after 28 days, while, the growth of lactic acid bacteria decreased but less than control film. Sensory properties of cheese samples packed in active films were not significantly changed. However, physicochemical characteristics such as pH and moisture content were affected significantly by active films. Overall migration of packaging active films in food simulants were within amounts allowed by national and international legislations.

Synergistic effects of organoclay Cloisite 15A on recycled polyethylene terephthalate

In this work, composites of recycled polyethylene terephthalate (PET-r) and organoclay Cloisite 15A (C15A) were strategically obtained by the intercalation method in the molten state. The synergistic effect of C15A with the recycled PET matrix was evaluated using different concentrations of C15A (1, 3, 5, and 7% wt). The influence of the C15A organoclay concentrations on rheological and thermal properties was investigated and corroborated with morphological observations. Both X-ray diffraction results and scanning electron microscopy analysis revealed that the obtained PET-r composites present a high degree of intercalation. The relaxation times measured from nuclear magnetic resonance also confirmed the synergistic interaction between the clay lamellae and PET-r matrix. The compatibility of the C15A with the polyester matrix is verified for the higher clay additions (5–7% wt) from the improved rheological properties in comparison to the neat PET-r. The higher C15A content (7% wt) provided an increment of 7 °C in the glass transition temperature and better thermal stability with an 11 °C increase in the composite degradation temperature. These beneficial results are associated with the higher number of processing cycles during the recycling and molding steps, which favor the chain size breakage and, thus, the clay lamellae are better dispersed in the PET-r matrix.

Electro-active control of the viscous flow and tribological performance of ecolubricants based on phyllosilicate clay minerals and castor oil

Lubricating fluids with highly improved tribological performance very often entail the use of environmentally disrespectful formulations. Based on organoclay dispersions in castor oil, the present research explores the development of simple and sustainable lubricants that enable an “active control” of the tribological behavior under the action of electric fields. Storage stable formulations with high electro-rheological (ER) performance were obtained with 2 wt% organo-modified montmorillonites (OMt) dispersions in castor oil. Their strong ER potential was assessed through the dynamic yield stress values obtained from steady flow curves at 25 °C under electric fields up to 4 kV/mm. Broadband dielectric spectroscopy measurements demonstrated a local maximum (or shoulder) in the dielectric loss, ε´´, in the frequency range 5–10 kHz which is related to interfacial polarization. It was found that the OMt clays had a much greater ER potential than other types of clay mineral (e.g. halloysite nanotubes) that did not exhibit any polarization relaxation in ε´´. Moreover, in general, a fairly good correlation of the yield stress values with the drop in the permittivity, Δε´ = ε0´ – ε∞´, was found for the OMt clays. Preliminary electro-tribological tests were carried out using a ball-on-three plates setup, with an optimal formulation prototype consisting of 2 wt% Cloisite 15A dispersion in castor oil. The results demonstrated a reduction of up to 9% of the friction coefficient in the mixed lubrication regime. This outcome, based on organo-modified layered nanosilicates dispersions in castor oil, revealed the feasibility of producing a “new generation” of lubricants which, with no need for hazardous chemicals, may assist in the development of a novel concept of lubrication through electric potentials.

PET/CLOISITE 15A composite fibers - studies on the structure and the flame inhibition mechanism

The improvement of poly(ethylene terephthalate) (PET) fibers flame retardancy is usually achieved by using antipyrenes, which may be incorporated into polyester molecules during polycondensation or are physically mixed with polymer in the fiber formation process. In this article we present an alternative method to reduce the flammability of PET fibers and fabrics which is analogous to dyeing them with a dispersed dyes in a high temperature bath. We have tested this method many times using various modifiers so far. This time, we applied a commercial organophilized montmorillonite Cloisite®15A (C15A). In the presented work, using Limited Oxygen Index (LOI) flammability tests and the thermogravimetric analysis (TGA) method, the effectiveness of the modification used was demonstrated and its optimal variant was determined. Based on Fourier Transform-Infrared Spectroscopy (FT-IR) studies, the existence of interactions between PET macromolecules and the C15A modifier in the entire temperature range of the oxidative degradation was confirmed. Using the Wide-Angle X-ray Scattering (WAXS) and Small-Angle X-ray Scattering (SAXS) methods, the basic parameters of the nanostructure of the studied fibers were determined, and their nanocomposite nature was confirmed. The most important goal, which was successfully achieved, was to explain the mechanism of flame inhibition by the applied modifier C15A.

Preliminary Insights into Electro-Sensitive Ecolubricants: A Comparative Analysis Based on Nanocelluloses and Nanosilicates in Castor Oil

The newest generation of lubricants needs to adapt to stricter environmental policies. Simple and sustainable formulations with tunable rheological properties under the action of electric potentials may be the key. The present research explored the feasibility of producing electro-sensitive ecolubricants based on nanocellulose (crystalline and fibrillar) or nanoclay (Cloisite 15A montmorillonite and halloysite nanotubes) dispersions in castor oil, at concentrations that ranged from 2 to 6 wt.%. Broadband dielectric spectroscopy (BDS) measurements allowed for a first estimate on the electro-responsive potential of the nanofluids. The nanocelluloses and the montmorillonite suspensions presented a relaxation event in the dielectric loss, ε″, centered at ca. 2–4 kHz, which is related to interfacial polarization. Moreover, their actual electro-rheological (ER) effect under high electric potentials up to 4 kV/mm was assessed by determining the magnitude of the yield stress from steady flow curves at 25 °C. It was found that the nanocelluloses and the montmorillonite showed an enhancement of three orders of magnitude in their yield stress values at 4 kV/m. This enhancement was much greater than in the halloysite nanoclay, which did not exhibit any polarization). This is the starting point for the development of environmentally friendly ER lubricating fluids, based on nanocellulose and montmorillonites (layered nanosilicates), which might assist in reducing the friction and wear through the application of controlled electric fields.

Physico‐mechanical, rheological and gas barrier properties of organoclay and inorganic phyllosilicate reinforced thermoplastic films

AbstractInsertion of 2:1 organo‐modified phyllosilicate tactoids into rheologically tough thermoplastics has extraordinary potential candidate in oxygen permeability and microstructural toughening. Herein, two commercially abundant clays have been taken for improvement of the thermoplastic's gas barrier property in reasonably low loading. The cause of low loading has been accounted to the usage of maleated polyethylene (MA‐g‐PE) during the melt mixing tenure. The optimized nanocomposite compression molded film has been tested against uniaxial stretching, which showed a negligible change in the residual permanent set with sacrificing the elongation at break feature. Moreover, nanoindentation was also performed to get the hardness of the sample surface. The flow behavior of the nanocomposites showed thixotropic likely with increasing the frequency. Oxygen transmission rate (OTR) has significantly decreased for tallow amine‐modified nanoclay system (cloisite 15A) in comparison to cloisite Na+ providing 'tortoise path' formation inside the matrix. Thus, hitherto, the work could demonstrate and provide the information of comparative studies between organo‐clay and simple phyllosilicates, which could be remediation of the loopholes in mechanical toughening and gas barrier lineaments.

Quantitative electron tomography of polylactic acid/clay nanocomposites for better comprehension of processing–microstructure–elastic modulus

The objective of performing transmission electron microscopy (TEM) tomography (TEMT) on poly (lactic acid) (PLA)/clay samples is to characterize their 3D microstructure by obtaining the dispersion distribution and orientation of the dimensions of the clays. This information cannot be elucidated from a qualitative TEM analysis or from conventional characterization techniques such as X-ray diffraction. The nanocomposites are obtained by mixing PLA with Cloisite 20A and 30B at different extrusion shear rates which have been analyzed in 3D. Quantitative TEMT is performed to all the nanocomposites and the resulting 3D quantitative characterization (geometry of clay particles misalignment degree and distribution) is used for a more realistic comprehension of the mechanical behavior of the nanocomposites.

Synthesis of montmorillonite/modified graphene oxide filler and its effect on the properties of PP composites

This work reports the easy production of hybrid organoclays composed of Cloisite 20A and modified graphene oxide (r-mGO) at different proportions, and their effect on PP composites properties. In this way, it is proposed to evaluate both, the effect of the amount of r-mGO in the hybrid organoclay, and the effect of the amount of the hybrid organoclay on the PP composites. Morphological and structural details of PP composites were followed by scanning electron microscopy and X-ray diffraction, respectively. The thermal stability of the composites was analyzed by thermogravimetric analysis and differential scanning calorimetry, tensile mechanical properties were also tested. The results show that the obtained laminated hybrid material exhibited homogeneous intercalation of Cloisite 20A and r-mGO. The interactions among the clay intercalant molecules and graphene oxide grafting makes them remain united even in a polymeric matrix, acting as a good reinforcer and resulting in a rigid polymeric composite with improved mechanical properties at low content of the filler, mainly when having small amounts of r-mGO.

Effect of organoclay modifier structure on the viscoelastic and thermal properties of poly(methyl methacrylate)/organoclay nanocomposites

Poly(methyl methacrylate) (PMMA)/clay nanocomposites (NCs) were prepared by suspension polymerization of methyl methacrylate in the presence of two different organoclays (Cloisite 30B, Cloisite 15A) with clay loading ranged from 0.5 to 5 wt%. Increase in molecular weight of the PMMA matrix with addition of the clay was revealed by gel permeation chromatography (GPC) and intrinsic viscosity measurements. As confirmed by X-ray diffraction (XRD), the NCs had an intercalated structure. The organoclays-MMA/PMMA compatibility was investigated by swelling tests and solubility parameter approach. Rheological behavior of PMMA NCs in molten state was analyzed through construction of master curves of complex viscosity, storage, and loss modulus by applying the time–temperature superposition procedure. Melt rheology, scanning electron microscopy (SEM), and UV/Vis spectroscopy results confirmed higher extent of clay dispersion in the NCs with Cloisite 30B. Compared to pure PMMA, all these NCs show increase of glass transition temperature as measured by DSC and improved thermal stability determined by thermogravimetric analysis (TGA). The results obtained by dynamic mechanical analysis showed that the storage modulus of the NCs was higher by incorporation of clay into the PMMA matrix, increasing as the amount of clay increased and that their mechanical performance was significantly enhanced.

Removal of levulinic acid from aqueous solutions by clay nano-adsorbents: equilibrium, kinetic, and thermodynamic data

In this research, the removal of levulinic acid from aqueous solutions was examined by using clay nano-adsorbents, namely montmorillonite and Cloisite 20A. The batch adsorption experiments were exerted at a different contact time (30–210 min), initial levulinic acid concentrations (20–100 g L−1), adsorbent amounts (0.05–0.25 g), and temperatures (25–45 °C). The equilibrium, kinetic, and thermodynamic data were obtained by using the adsorption capacities of clay nano-adsorbents. It was found that Cloisite 20A exhibited a higher adsorption capacity than montmorillonite. Different adsorption isotherm and kinetic models were utilized to explain the adsorption mechanism and the parameters of these models were determined. Moreover, the thermodynamic analysis was performed to express the adsorption process. For the adsorption of levulinic acid on both clay nano-adsorbents, the adsorption equilibrium data were well represented by the Freundlich isotherm model and the adsorption kinetic data were well characterized by the pseudo-second-order kinetic model for the removal of levulinic acid by two clay nano-adsorbents.

Optimization of antibacterial and mechanical properties of an active LDPE/starch/nanoclay nanocomposite film incorporated with date palm seed extract using D-optimal mixture design approach

A novel active LDPE/TPS nanocomposite films containing date palm seed extracts (Kabkab variety) were developed using D-optimal mixture design. 20 different blends of components including LDPE, TPS, Cloisite 20A, PE-g-MA, EDTA and date palm seed extract in different proportions were prepared. Using trace and counter plots the effects of each component on the mechanical and antibacterial properties of the composites were studied. The results showed that the films containing a mixture of date seed extract and EDTA had notable antibacterial activity against E. coli and S. aureus; however, these components weakened the mechanical properties of the prepared films. At the same time Cloisite 20A nanoparticles strengthened the films mechanical properties.The optimized formulation for the overall best antibacterial and mechanical properties was 67.5 wt% for LDPE, 4.1 wt% for date seed extract, 2.8 wt% for Cloisite 20A and 2.5 wt% for EDTA. The studied properties of the manufactured film samples were close to the values predicted by the model.

Study on the Morphology and Fiber Properties of Nanoclay Added Polyvinyl Alcohol (PVA) Nanofibrous Mats: Effect of Mechanical Dispersion

In this study, polyvinyl alcohol (PVA) polymer and Cloisite 15A, a modified form of organo Montmorillonite nanoclay, are used to produce nanofibrous mats via electrospinning technique. Pure PVA nanofibrous mats from mechanically stirred polymeric solutions at 8, 10 and 12 wt % PVA percents; and nanoclay added PVA nanofibrous mat samples are produced at increased nanoclay weight/ polymer weight ratios (1/13, 1/11, 1/9 and 1/6) using several mechanically stirred nanoclay-PVA solutions at various proportions of nanoclay and PVA polymer wt % in solutions. The viscosities, surface tensions and electrical conductivities of solutions were measured. FESEM (Field Emission Scanning Electron Microscopy) analysis, fiber diameter distribution with Image J software analysis and tensile testing was applied to nanofibrous samples. Increased polymer concentration led to bead-free nanofibrous PVA mats. EDX analysis approved nanoclay is present in samples produced from nanoclay added PVA solutions. Mechanical stirring for nanoclay dispersion enabled smooth nanofibrous structures only in low (1/13) nanoclay weight/ polymer weight ratios and showed very little tensile increase from 1 wt % clay loading to 2 wt % addition. A direct increase in tensile strength wasn’t achieved with nanoclay content increase in PVA nanofibrous mats; this might be due to the effect of poor nanoclay distribution adversely affecting tensile results. Morphological analysis proved that nanofibrous structures were far away from smooth fiber structures as they transformed from smooth nanofibers into non-uniform fibrous structures at increased nanoclay weight/ polymer weight ratios in nanoclay added PVA samples. Keywords: nanofibrous mat, electrospinning, polyvinyl alcohol (PVA), nanoclay, mechanical dispersion DOI : 10.7176/CPER/62-08 Publication date: May 30 th 2020

Organic modifier induced interfacial transformation, morphology and physico-mechanical properties of PP/NR based blend nanocomposites

The influence of incorporating organic modified nanoclay (Cloisite 10A) (C 10A) on the morphology, interfacial characteristics, and physico-mechanical properties of polypropylene (PP) melt blended with natural rubber (NR) is investigated here. Melt-mixing technique was employed to prepare nanocomposites with varying amounts of C 10A (1, 3, 5, 7 phr). Nanoclay, depending on its concentration, ‘instigated dramatic transformation of phase morphology from a co-continuous type to a non-uniform sea-island type leading to well-defined matrix-droplet morphology. Besides, addition of nanoclay refined the phase morphology and effectuated synergistic improvement in physico-mechanical properties, where 3 wt% nanoclay modified system exhibited optimal properties for end use application in automotive industry thereby establishing the morphology-property correlation.