Commercial Organoclay Research Articles

Chain extension of poly(butylene terephthalate)/organically modified clay nanocomposites

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

Engineering porous clay nanoarchitectures from unusual commercial organoclay: Supported manganese oxide as stable catalysts in the total oxidation of volatile organic compounds

The porous engineering of clay nanoarchitectures (PCN) achieved from a well-known but little-explored commercial organoclay C-20A is reported. Thorough characterizations (by XRD, TGA, N2 sorption, ICP, SEM, TEM, 27Al MAS NMR, DR UV-Vis, XPS, Py-FTIR and H2-TPR) confirmed a delaminated structure presenting a specific surface area of 504 m² g−1, twelve times higher than the sodic montmorillonite used as reference and featuring a new pore system comprising a size range from supermicropores to small mesopores (1.3–10 nm). The role of these PCN as support of manganese oxide for the gas-phase total catalytic oxidation of volatile organic compounds (VOCs) was evaluated. PCN with 5 % of Mn resulted in a higher nanoparticle dispersion (10 nm) compared to the sodic montmorillonite (17 nm). The highest catalytic activity was reached with PCN containing 10 % of Mn achieving a benzene, toluene and ortho-xylene oxidation of 54 %, 39 % and 34 %, respectively, at 350 °C. The catalyst was stable up to 36 h under these conditions.

Adsorption of sulfamethoxazole and ethofumesate in biochar- and organoclay-amended soil: Changes with adsorbent aging in the laboratory and in the field

Biochars and organoclays have been proposed as efficient adsorbents to reduce the mobility of agrochemicals in soils. However, following their application to soils, these adsorbents undergo changes in their physicochemical properties over time due to their interaction with soil components. In this study, the adsorption capacity of a commercial biochar and a commercial organoclay for the antibiotic sulfamethoxazole (SFMX) and the pesticide ethofumesate (ETFM) was evaluated over aging periods of 3 months in the laboratory and 1 year in the field, subsequent to their application to a Mediterranean soil. The results showed that the adsorption of SFMX and ETFM in the soil amended with the adsorbents was greater than in the unamended soil, but for both chemicals, adsorption decreased with aging of the adsorbents in the soil. Characterization of the adsorbents before and after aging revealed physical blocking of adsorption sites by soil components. The loss of adsorption capacity of the adsorbents upon aging led to higher leaching of SFMX and ETFM in the soil containing field-aged adsorbents, although leaching remained lower than in unamended soil. Our findings reveal that, under the Mediterranean environment studied, the efficacy of the studied materials as adsorbents is maintained to a considerable extent for at least one year after their field application, which would have positive implications in their use for attenuating the dispersion of agricultural contaminants in the environment.

Effect of the Intercalation and Dispersion of Organoclays on Energy Demand in the Extrusion of Recycled HDPE/PP Nanocomposites

Few studies have drawn on any systematic research into the energy demand to produce polymer-based nanocomposites. Regarding the problem, it is well-known that single screw extrusion is an energy-intensive process, so the incorporation of energy meters must be considered to examine the energy efficiency of the process. In this study, the effect of a nanoclay addition on the energy demand of the extrusion process was examined by extruding recycled high-density polyethylene (rHDPE) and recycled polypropylene (rPP) with a gradual compression screw with both dispersive and distributive mixers. The rHDPE/rPP was modified by adding commercial organoclay (OMMT) (3 wt%) and olefin block copolymer (OBC) (5 wt%) as compatibilizers. The energy consumption was measured on the total energy of the extruder machine. Mass throughput (MT) and specific energy consumption (SEC) were obtained at different screw speeds (10, 20, 30, 40, 50 RPM). The SEC of OMMT and OMMT/OBC nanocomposites was 25–50% lower than rHDPE/rPP, especially at higher throughputs. X-ray diffraction (XRD) and scanning electron microscope (SEM) illustrated the degree of intercalation and dispersion of the organoclay at different screw speeds. Better organoclay intercalation and dispersion were found at lower temperatures. Rheological curves showed a decrease in the viscosity at extrusion rates of nanocomposite mixtures. Melt temperature measured at die exit was reduced in the presence of organoclay over the screw speeds studied. This work suggests that the processing of rHDPE/rPP based nanocomposites can result in minor costs when processing conditions are carefully selected.

Thermal behavior of polyethylene terephthalate/organoclay nanocomposites: investigating copolymers as matrices

AbstractPolyethylene terephthalate (PET)/clay nanocomposites have been widely studied. However, different PET copolymers are also produced in large scale but not commonly investigated as matrices for nanocomposites. In this work, PET‐based nanocomposites, with PET homopolymer and two PET copolymers as matrices, were prepared by melt blending with a commercial organoclay. The focus of this study was to investigate the thermal behavior of these materials by differential scanning calorimetry and thermogravimetric analysis and to provide a satisfactory crystallization kinetic modeling. X‐ray diffraction analysis showed that the nanocomposites exhibited clay intercalation. The glass transition temperature and the thermal stability of the materials decreased with an increase in clay content. The presence of clay did not affect the degree of crystallinity developed by the materials, although it caused the anticipation and acceleration of the crystallization events. A discussion is made about the application of a modified Avrami model for non‐isothermal crystallization and its validity. The modified Avrami model has proven to be a good choice for the non‐isothermal crystallization kinetic modeling of these nanocomposites under various heating/cooling rates, being useful for simulations under processing conditions.

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.

Adsorption of diclofenac sodium onto commercial organoclay: Kinetic, equilibrium and thermodynamic study

The presence of pharmaceutic compounds has been widely detected in water and wastewater due to the increase in their production and consumption. Since conventional treatments are not able to totally remove these microcontaminants, more efficient technologies, such as adsorption, must be investigated. This study aimed to evaluate the adsorption of diclofenac sodium (DS) onto commercial organoclay (Spectrogel® Type C) in static system. Process optimization was performed through Central Composite Design (CCD) and the adsorbent mass of 0.5 g and agitation speed of 200 rpm were selected as the optimum conditions. The variable initial concentration of DS was not statistically significant. Pseudo-first order model showed the best correlation to kinetic experimental data and the investigation of adsorption mechanism revealed that external mass transference was the main rate-controlling step. Equilibrium data obtained at 15 °C and at 30 °C were best described by Freundlich isotherm model and at 50 °C by Temkin isotherm model. The maximum adsorption capacity from Langmuir was of 0.133 mmol/L at 50 °C. Thermodynamically, the process is spontaneous and endothermic. Characterization analysis depicted that DS adsorption takes place on the surface of Spectrogel, which is not significantly modified by the process.

Effect of organoclay and preparation method on properties of antimicrobial cellulose acetate films

The aim of the present study was oriented to evaluate the effect of a commercial organoclay and the technique of preparation on the physical and antimicrobial properties of active eco‐friendly nanocomposites films. To this antimicrobial nanocomposite films were fabricated from cellulose acetate (CA) powder, triethyl citrate (TEC) plasticizer, a commercial organoclay Cloisite30B (C30B), and cinnamaldehyde (Ci) as active agent. All nanocomposites showed the intercalation of the polysaccharide inside the organoclay structure, however, the level of the intercalation and the quality of the clay dispersion were dependent on the method selected to prepare them (solution‐casting or extrusion). In addition, nanocomposites obtained by extrusion evidenced a better dispersion of organoclay. Important changes on the color properties of films were evidenced, which was associated to the thermal degradation of the quaternary ammonium surfactant of the Cloisite30B. On the other hand, organoclay was unable to reduce the cinnamaldehyde loss during the extrusion and storage, nevertheless, a slight effect of the Cloisite30B on the cinnamaldehyde release to a food simulant was observed to nanocomposites prepared by extrusion. Finally, despite cinnamaldehyde loss was observed over time, the content of residual active compound into the films was able to impart antimicrobial activity against Escherichia coli for 14 weeks. POLYM. COMPOS., 40:2311–2319, 2019. © 2018 Society of Plastics Engineers

Fixed Bed Adsorption of Benzene, Toluene, and Xylene (BTX) Contaminants from Monocomponent and Multicomponent Solutions Using a Commercial Organoclay

Benzene, toluene, and xylene (BTX) are potential contaminants of groundwater, and there is a need to improve current remediation techniques, such as adsorption. Different materials can be applied in this process, like organoclays that have affinity for organic compounds. The aim of this work was to study BTX removal from mono-, bi-, and tricomponent solutions in a dynamic fixed bed system filled with organoclay. For the monocomponent system, using a 1.6 mmol/L adsorbate concentration, the useful removal quantities were 0.012, 0.030, and 0.140 mmol/g for benzene, toluene, and p-xylene, respectively. Based on the results, the affinity order was p-xylene > toluene > benzene. The multicomponent tests presented similar affinity tendency toward the organoclay. The mathematical model of Yan described the majority of the experimental breakthrough curves better than the model of Thomas. Partition was identified as the prevailing mechanism in BTX uptake, and the main adsorption sites were associated with the nanosi...

Adsorption of benzene, toluene, and xylene (BTX) from binary aqueous solutions using commercial organoclay

AbstractOrganoclays are promising alternative adsorbents for the removal of organic pollutants. The aromatic hydrocarbons benzene, toluene, and xylene (BTX) are typical petroleum contaminants found simultaneously in natural leaking. Therefore, investigations on multi‐component adsorption become essential to study this issue. Based on that, in the present study, a commercial organoclay from Brazil has been tested for its adsorption potential for binary aqueous mixtures of BTX. Kinetic and equilibrium batch adsorption experiments were performed to elucidate the differences in the affinities between the BTX contaminants and the organoclay. The kinetic study indicated that for benzene‐toluene, benzene‐xylene, and toluene‐xylene systems the contaminants preferentially adsorbed were toluene, p‐xylene, and p‐xylene (in the beginning of the assays), respectively. The affinity for the organoclay might be related to physicochemical properties of BTX. In the adsorption equilibrium studies, the obtained BTX isotherms were all linear, characterized by constant adsorption affinities. The observed differences between BTX adsorption capacities at equilibrium for mono and bi‐component systems confirmed the competition for adsorption sites of the organoclay.

Impact of salinity and dispersed oil on adsorption of dissolved aromatic hydrocarbons by activated carbon and organoclay

Adsorption capacity of phenol and naphthalene by powdered activated carbon (PAC), a commercial organoclay (OC) and a lab synthesized organoclay (BTMA) was studied using batch adsorption experiments under variable feed water quality conditions including single- and multi- solute conditions, fresh water, saline water and oily-and-saline water. Increasing salinity levels was found to reduce adsorption capacity of OC, likely due to destabilization, aggregation and subsequent removal of organoclay from the water column, but did not negatively impact adsorption capacity of PAC or BTMA. Increased dispersed oil concentrations were found to reduce the surface area of all adsorbents. This decreased the adsorption capacity of PAC for both phenol and naphthalene, and reduced BTMA adsorption of phenol, but did not negatively affect naphthalene removals by either organoclay. The presence of naphthalene as a co-solute significantly reduced phenol adsorption by PAC, but had no impact on organoclay adsorption. These results indicated that adsorption by PAC occurred via a surface adsorption mechanism, while organoclay adsorption occurred by hydrophobic or pi electron interactions. In general, PAC was more sensitive to changes in water quality than either of the organoclays evaluated in this study. However, PAC exhibited a higher adsorption capacity for phenol and naphthalene compared to both organoclays even in adverse water quality conditions.

Adsorption of toluene into commercial organoclay in liquid phase: Kinetics, equilibrium and thermodynamics

Organoclays are usually used as sorbents to reduce the spread of organic compounds and to remove them at contaminated sites. This study investigated the liquid‐phase adsorption of toluene on organoclay (Spectrogel® Type C) of Brazilian company SpectroChem. In spite of not having a large amount of pores, this organoclay is a low‐cost, effective adsorbent. Regarding the pH investigations, considerable effects of pH on the adsorption process were not observed. In the kinetics studies, it was observed that the process comes into equilibrium after 1 h with rates of about 90 % toluene removal. The experimental kinetic data were best fitted by a mass transfer in external film model. For the equilibrium study, the best fit was by the MSAM model at 288.15 K, the Dubinin‐Radushkevitch model at 298.15 K, and the Sips model at 308.15 K. Further, the thermodynamic parameters showed that toluene adsorption on organoclay Spectrogel‐C is an endothermic process. For tests of regeneration, ethanol was the eluent, which proved more promising.

Structure and properties of nanocomposites based on poly(butylene succinate) and supercritical carbon dioxide-processed montmorillonite

Montmorillonite is intercalated with different amounts of tetradecyltrihexylphosphonium chloride in supercritical carbon dioxide and poly(butylene succinate)-based nanocomposites are prepared with the organically modified or commercial organoclay via melt-mixing. The effect of amount of tetradecyltrihexylphosphonium chloride on the structure of organically modified montmorillonite tactoids, organically modified montmorillonite dispersion and finally on properties of nanocomposites is systematically investigated. Different from the compact spherical structure for pristine montmorillonite tactoids, flexible expanded structure with large cavities on the surface can be obtained for organically modified montmorillonites, and their structure show slight difference with the tetradecyltrihexylphosphonium chloride amount. It is interesting to find that, despite almost no polymer molecule being intercalated into the interlayer, significant dispersion can be achieved for the scCO2-processed organically modified montmorillonite in polymer matrix, due to the easily broken tactoid structure. It is noteworthy, montmorillonite-tetradecyltrihexylphosphonium chloride 08, which is modified with 0.8 CEC tetradecyltrihexylphosphonium chloride, less than in most of the literature, shows almost the same degree of dispersion in poly(butylene succinate) matrix as commercial montmorillonite, which has a stronger interaction with the polymer. Differential scanning calorimetry and dynamic modulus analysis results demonstrate that the crystallization temperature and storage modulus of poly(butylene succinate)-based nanocomposites increase with the amount of tetradecyltrihexylphosphonium chloride, and montmorillonite-tetradecyltrihexylphosphonium chloride08/poly(butylene succinate) shows even higher crystallization temperature and low-temperature storage modulus compared to commercial montmorillonite/poly(butylene succinate).

Effect of organoclay and compatibilizers on microstructure, rheological and mechanical properties of dynamically vulcanized EPDM/PP elastomers

Dynamically vulcanized thermoplastic elastomers (TPVs)/oraganoclay nanocomposites were successfully fabricated from polypropylene with ethylene propylene diene monomer (EPDM). Two types of compatibilizers, ethylene propylene diene monomer grafted maleic anhydride and polypropylene grafted maleic anhydride, were incorporated to improve the dispersion of commercial organoclay (15A). In the present work, the role of interfacially located organoclay on the coalescence in TPV nanocomposites was investigated systematically with contact angle measurements and theoretical models to ensure their localization at the polymer/polymer interface, which is experimentally verified by scanning electron microscopy and atomic forced microscopy. Using a rheological method it was shown that coalescence of the dispersed phase is slowed down when organoclay is present at the interface. With the increase of organoclay contents, the size of EPDM droplet decreased due to the in situ formed brush-like interface around the compatibilized EPDM droplet. It was shown that the mechanical properties were improved due to good dispersion of organoclay in the compatibilized TPV nanocomposites.

Silylated montmorillonite as nanofillers for plasticized PVC nanocomposites: Effect of the plasticizer

Poly(vinyl chloride) (PVC) nanocomposites were prepared by compounding PVC with different clay minerals, which were previously dispersed into dioctyl phthalate (DOP) or epoxidized soybean oil (ESO) as plasticizers, with the help of an ultrasonication. Sodium montmorillonite (Na+-Mt) and those obtained from its functionalization with N-(2-aminoethyl-)-3-aminopropyl-trimethoxy-silane (NH2-Mt) or 3-mercaptopropyl-trimethoxy-silane (SH-Mt), as well as a commercial organoclay, Cloisite 30B, were employed as the nanoparticles. The incorporation of amino or mercaptosilane on the Na+-Mt surface was estimated by Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD) and thermogravimetric analysis (TGA). The clay PVC nanocomposites containing 2.5phr of different clay minerals were characterized by XRD, dynamic mechanical analysis, thermal degradation and dielectric analysis. It was found a high exfoliation degree for the nanocomposites containing silylated clays, as suggested by the absence of reflections. Na+-Mt also displayed a high exfoliated structure for system plasticized with ESO. The presence of different clay minerals resulted in an increase of the storage modulus without affecting the glass transition temperature. Regarding thermal stability, those systems plasticized with ESO presented the best results obtained from thermogravimetric analysis, and the presence of Cloisite 30B, a clay mineral modified with ammonium salt, presented the worst performance in both plasticized systems.

Preparation of PET/clay nanocomposites via in situ polymerization in the presence of monomer‐activated organoclay

Various polyethylene terephthalate (PET)/clay nanocomposites containing a commercial organoclay (organophilic montmorillonite nanoclay [OMMT]) and a monomer‐activated OMMT (remodified OMMT) were prepared via in situ interlayer polycondensation of dimethyl terephthalate and ethylene glycol. In order to remodify the commercial OMMT nanoparticles, a diacid chloride monomer was applied. The prepared nanocomposites were characterized by diverse methods, including X‐ray diffraction, differential scanning calorimetry, thermogravimetric analysis, and intrinsic viscosity measurements. The results of the study revealed that the PET/(remodified OMMT) nanocomposites possess a better state of clay dispersion as well as significantly better thermal properties as compared with the PET/OMMT nanocomposites. Moreover, the PET/(remodified OMMT) nanocomposites showed higher crystallization temperature, degree of crystallinity, maximum degradation temperature, and lower half‐time of crystallization than that of the PET/OMMT nanocomposites. It was found that the remodification process for OMMT led to less of a foaming problem during in situ polymerization. J. VINYL ADDIT. TECHNOL., 21:70–78, 2015. © 2014 Society of Plastics Engineers

Enhancements of clay exfoliation in polymer nanocomposites using a chemical blowing agent

AbstractA novel approach, via the use of a blowing agent (BA), to enhance clay exfoliation in polymer nanocomposites is reported. A commercial organoclay was treated with a common low‐cost BA, which was then melt‐processed with polymers in an extruder. The characterization results revealed that the degrees of exfoliation of the clay were increased when using BA. Consequently, the resultant nanocomposites exhibited improvements in thermal degradation temperature as compared to their corresponding polymers and nanocomposites without the involvement of BA. They also presented simultaneous improvements in stiffness, strength, ductility and toughness. These property enhancements were mainly attributed to the presence of BA in clay interlayers which degraded during melt compounding, generated gases and pushed clay layers apart, facilitating clay exfoliation under the shear forces. This work demonstrates the potential of using a BA to produce high‐performance polymer/clay nanocomposites by melt processing. © 2014 Society of Chemical Industry

Binary and ternary nanocomposites based on PVDF, PMMA, and PVDF/PMMA blends: polymorphism, thermal, and rheological properties

Binary and ternary nanocomposites based on poly(vinylidene fluoride) (PVDF), poly(methyl methacrylate) (PMMA), and PVDF/PMMA blends were successfully prepared through a melt-mixing process, using a commercial organoclay (15A) as the nanofiller. The 15A was more finely dispersed (intercalated/partially exfoliated) within the PVDF matrix compared with the PMMA matrix. A higher PVDF content in the ternary composite essentially led to a superior degree of 15A dispersion. The 15A addition induced the polar β-form PVDF crystals, whereas the presence of PMMA in ternary composites reduced the efficiency in promoting β-form formation by 15A. Adding 15A also enhanced the nucleation of PVDF, but the enhancement was inferior while PMMA was present. Conversely, the crystal growth of PVDF was retarded with the existence of 15A, and the PVDF/15A binary composite exhibited the greatest retardation. The equilibrium melting temperature (Tm°) of PVDF in the neat state and in the blends increased after 15A addition. The PVDF/15A binary composite possessed an evidently higher β-form Tm° than the α-form Tm° of neat PVDF (~20.1 °C rise). Similar effects on the individual components, 15A declined the thermal stability of PVDF but increased that of PMMA in the ternary composites. Rheological property measurements revealed that the ternary composites performed in-between that of individual PVDF/15A and PMMA/15A binary composites. A percolation of 15A (pseudo)network structure was developed in the composites, and a more elastic behavior was observed with increasing PVDF content in the composites.

Polypropylene/organoclay/SEBS nanocomposites with toughness–stiffness properties

Polypropylene nanocomposites with a different amount of styrene-ethylene-butylene-styrene block copolymer (SEBS)/clay were prepared via a melt mixing technique. To improve the dispersion of commercial organoclay (denoted as OMMT), various amounts of SEBS were incorporated. At a fixed content of OMMT, the mechanical properties were improved with increasing SEBS content. The obtained nanocomposites were characterized through X-ray diffraction (XRD), differential scanning calorimetry (DSC-TG) and mechanical tests. The thermal–morphological–mechanical properties were investigated. The nanomaterials presented an improved decomposition temperature, a small decrease in tensile strength, a higher Young's modulus and a spectacular increase of 300% in impact strength.

Effect of organoclay on blends of individually plasticized thermoplastic starch and polypropylene

Cornstarch and polypropylene (PP) blends were prepared by melt mixing at a constant 70:30 (mass/mass) ratio in a co-rotating twin-screw extruder. Both components were plasticized individually; glycerol and acetyl tributyl citrate (ATBC) were used as plasticizers for starch and PP, respectively. A commercial maleated polypropylene (mPP) was added to the mixtures as a compatibilizing agent. A commercial organoclay was also incorporated at increasing contents (1.0, 2.5 and 5.0mass% over the total mass of the blends). The extruded materials were pelletized, compression-molded, and characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), thermogravimetric analysis (TGA), dynamic mechanical analysis (DMA) and capillary rheometry. XRD results indicated that the addition of ATBC contributed to the increase of PP crystallinity from 62% to 72%. The incorporation of the organoclay caused alterations inside the PP-dispersed phase, particularly when its composition reached the amount of 5.0mass%. SEM images revealed a coarse morphology for the blend prepared in the presence of mPP alone. XRD, SEM and DMA data revealed that improvements in the compatibility between the immiscible components were achieved by the organoclay incorporation. The evolution of the XRD patterns for the hybrid materials submitted to aging at high humidity conditions for 120 days indicated that organoclay particles were located preferentially in the starch matrix at the end of this experiment.