Different Types Of Organoclays Research Articles

Development of emulsified acid system (EAS) using organoclays (OC): Rheology and implication to the acidizing

Matrix acidizing is a well-stimulation technique extensively used in the petroleum industry to increase well productivity by removing scales and creating channels in the rocks. However, conventional acidizing fluids used in this process have some limitations such as rapid reactions with scale and fines, high acid strength, and corrosion of equipment at high temperatures. To address these issues, emulsified acid system (EAS) is used in fracturing and acidizing operations for carbonate reservoirs to improve well productivity by removing formation damage. EAS can help to improve well productivity by creating deeper and narrower wormholes through reduced reaction rates of acid due to the external oil phase. However, EAS has limitations such as low stability at high temperatures, high viscosity that restricts pumping rates, potential formation damage, and difficulty in achieving homogenous mixing. Pickering emulsions, which use solid microparticles as a stabilizer instead of surfactants, show promise in overcoming these challenges due to their easy preparation, good thermal stability, and low viscosity at high shear rates.This study investigates the use of different types of organoclays (OC) for the development of an emulsified HCl acid systems for carbonate reservoirs. Several experiments were conducted to demonstrate and evaluate the use of OC for EAS and to improve field operations. To advance the development of EAS, a meticulous process was undertaken to select and optimize OCs as the key component. It include mineral characterization by XRD and XRF techniques, optimization of OC concentration (250–1000 ppm), and mixing speed (4000–8000 RPM). The thermal stability of the EAS was evaluated for a temperature range of 25–160 °C and a comprehensive analysis of EAS rheology (0.1–1000 sec−1) was performed. The conductivity, drop-test analysis, as well as micrographic analysis, were carried out to ensure the formation of invert emulsion. It was found that the required mixing speed was 6000 RPM and the optimum OC concentration was 500 ppm for developing a stable invert emulsion. The viscosity of the EAS shows increasing trends with an increase in temperature at the low shear rates (below 10 sec−1); however, at high shear rates (higher than 10 sec−1), the EAS viscosity decreases with temperature. The study found that OCs are promising emulsifiers for creating EAS with good thermal stability and low viscosity at high shear rates. The EAS formulated using OC were robust and thermally stable, making them suitable for field mixing procedures. Additionally, the OC used in the study are cost-effective, readily available, environmentally friendly, and have a high surface area, making them advantageous as an emulsifier.

Mechanical, thermal and rheological characterization of polystyrene/organoclay nanocomposites containing aliphatic elastomer modifiers

In this study, organoclay containing polystyrene (PS) based nanocomposites were prepared by extrusion in the presence of aliphatic elastomer modifiers. Three different types of aliphatic elastomeric materials and three different types of organoclays were used. Their effects on the morphology, and mechanical, thermal, and rheological properties of PS were investigated by scanning electron microscopy (SEM), transmission electron microscopy (TEM) and x-ray diffraction (XRD), tensile and impact tests, differential scanning calorimetry (DSC), and melt flow index measurements, respectively. Lotader AX8900, Lotader AX8840 and Lotader 2210 were chosen as the aliphatic elastomeric compatibilizers; and Cloisite 15 A, Cloisite 25 A and Cloisite 30B were chosen as the organoclays. The organoclay content was kept constant at 2 wt% and elastomer content was kept constant at 5 wt% throughout the study. Significant improvement is observed on the basal spacing for 30B containing samples according to XRD analysis. SEM studies indicate that the clay particles mostly reside between the PS matrix and the spherical elastomeric domains. Additions of elastomer and organoclay decrease the MFI value of PS. Mechanical test results show that, improvement is observed in elongation at break of unfilled PS with the addition of elastomers. Organoclay addition increases the tensile modulus of PS. According to thermal characterizations, the glass transition temperature (Tg) of PS decreases with elastomer addition, whereas organoclay addition shifts Tg values to higher temperatures.

Polylactide/organoclay nanocomposites: The effect of organoclay types on the structure development and the kinetic of cold crystallization

Polylactide (PLA)/organoclay composites were prepared by melt compounding with 4 phr of two different types of organoclays (cloisite 20A and cloisite 30B). Structure development and nonisothermal kinetic of cold crystallization of PLA/organoclay nanocomposites were examined by using of X‐ray diffraction technique, transmission electron microscopy, melt viscoelastic measurements, and differential scanning calorimetry. XRD results demonstrated that the melt intercalation of PLA chains into the cloisite 30B and cloisite 20A galleries was achieved to the same extent. However, it was shown that, PLA/cloisite 20A sample exhibited a significant viscosity upturn and a pronounced nonterminal low frequency storage modulus whose values were greater than those of PLA/cloisite 30B nanocomposite. A detailed analysis of the linear melt viscoelastic properties for the filled and unfilled samples at low frequencies was conducted by fitting the complex viscosity and storage modulus data with Carreau–Yasuda and Fractional Zener models, respectively. The glass transition, cold crystallization, melting temperature, and degree of crystallinity of virgin PLA and PLA/organoclay nanocomposites were inspected. Subsequently, the cold crystallization kinetics was analyzed by Avrami, Jezioney, and Lauritzen–Hoffman kinetic models. It was shown that, the crystallization rate followed Avrami equation with the exponent n around 2.4. From Lauritzen–Hoffman equation and Kissinger model, the nucleation parameter Kg and activation energy were estimated, respectively. J. VINYL ADDIT. TECHNOL., 25:48–58, 2019. © 2018 Society of Plastics Engineers

An experimental study on composite adhesives reinforced with different types of organo-clays

ABSTRACTIn this study, the mechanical properties of single lap joints prepared by adding nanoclays with different properties into adhesives with different characteristics (toughened, flexible, paste-type, and rigid) were experimentally investigated. Single lap joints and bulk specimens were produced using DP460, DP125, Araldite 2015, and AV138 as adhesives. High-concentration hydrocarbon-doped organo-clay (HDOC-1) obtained from Çankırı, low-concentration hydrocarbon-doped organo-clay (HDOC-2) obtained from Erzurum, and organo-clay (OC) were incorporated into the adhesives as reinforcements at two different concentrations (1% and 2% wt.). The aluminum alloy AA2024-T3 was used as the adherend material. Evaluation of experiment results showed that both the characteristics of the adhesive (toughened, flexible, paste-type, and rigid) and the different forms of clays significantly influenced failure loads of the joints. Moreover, increasing or decreasing the amount of clay added into the adhesive also affected failure loads of the joints; 1% wt. reinforcement provided the best results.

Effect of electric field on polymer/clay nanocomposites depending on the affinities between the polymer and clay

ABSTRACTApplying an electric field is an efficient way to fabricate polymer/clay nanocomposites. It helps to achieve a good dispersion of nanoclays which improves the performance of the polymeric system. In this study, the effect of an alternating current (A.C.) electric field was investigated on clay exfoliation with various combinations of polymer/clay nanocomposites. Three different types of organoclays (Cloisite 10A, 20A, 30B) were introduced in polypropylene (PP) and poly(lactic acid) (PLA) matrices. Their rheological properties showed that the A.C. electric field was effective in enhancing the dispersion of organoclays in both the PP/clay and PLA/clay composites. The efficiency of the A.C. field varied depending on the combination of polymer and clay nanoparticles. In the case of PP, the best combination was PP/C20A followed by PP/C10A and PP/C30B. In contrast, PLA/clay showed an opposite trend. This difference arises from the different affinities between the polymers and the functional groups of the clays. The Hansen solubility parameter was introduced to quantify the affinities between the polymer and clay. The electric field was more effective for polymer/clay combinations that had less difference in the Hansen solubility parameter. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016, 133, 43582.

The role of layered silicate loadings and their dispersion states on the gas separation performance of mixed matrix membrane

Mixed matrix membranes (MMMs) embodying different types of organoclays, namely Cloisite® 5, Cloisite® 15A and Cloisite® 30B as the disperse phase for gas separation membranes, were prepared. Polysulfone (PSF) has been used as host matrix to prepare asymmetric membranes attained by the dry–wet phase inversion casting process. FESEM analysis has revealed that defect-free asymmetric MMM morphology with no issues pertaining to non-ideal organic–inorganic interphase was fabricated. The effects of organoclay types and loadings on gas permeation properties were characterized by constant pressure and the variable volume method. From the gas permeation experiment, all nanocomposites exhibited significant reduction in the gas permeation rate even with the addition of very low clay loadings (less than 1wt%). The results suggested that the clay particle loading dictated the extent at which the organoclays were dispersed in the polymer matrix as well as their gas discrimination ability. The information on the degree of clay dispersion, aspect ratio, and the number of clay stacks per tactoid unit was gleaned by making use of the famous phenomenological models derived by Nielsen and Cussler׳s group. PSF–C15A membranes with the loading of 0.05wt% were found to be comprised of exfoliated clay nanoplatelet (confirmed by XRD and TEM analysis) with calculated aspect ratio of more than 500 giving rise to striking selectivity (CO2/CH4 ideal selectivity=52.67 for PSF–C15A0.05) well above the recognized intrinsic selectivity for PSF membrane.

Bio-based semi-aromatic polyamide/functional clay nanocomposites: preparation and properties

In this paper we first describe the design and synthesis of two novel cationic functional modifiers, i.e. a functionalized β-cyclodextrin (β-CD) derivative and tris(3-aminophenyl)phenyl phosphine oxide (TAP). Cloisite Na+ (clay-Na) and the modifiers were used for the preparation of the organoclay containing phosphine oxide (clay-PO) and of the organoclay containing β-cyclodextrin (clay-CD) via ion-exchange reaction. Biobased semi-aromatic polyamide (BPA)/functional clay (clay-PO and clay-CD) nanocomposites subsequently were prepared via solution blending. Effects of the two different types of organoclays on the flammable, thermal and mechanical properties of these biobased semi-aromatic polyamide nanocomposites were then studied. The properties of the nanocomposites were found to be strongly related to the nature of the modifiers. The clay-CD based nanocomposites (BPACD) showed more enhancements in thermal stability. The modifier containing the phosphine oxide moiety and triamine groups had stronger interactions with the polymer matrix, and exhibited superior mechanical properties, good flame retardancy and high thermal stability. Thus, we provide a new approach for comprehensive improvement of the properties of these bio-based semi-aromatic polyamide nanocomposite materials.

Effect of clay structure and type of organomodifier on the thermal properties of poly(ethylene terephthalate) based nanocomposites

In the current investigation, nanocomposites of poly(ethylene terephthalate) (PET) with different types of organo-clays were produced using the melt mixing technique. Two types of commercial inorganic clays (Laponite-synthetic hectorite and Kunipia-montmorillonite) were studied after cation-exchange with hexadecyltrimethylammonium bromide (CTAB) while two commercial organo-modified montmorillonite clays (Nanomer I.30E modified with primary octadecylammonium ions and Cloisite 10A modified with quaternary dimethyl benzyl hydrogenated-tallow ammonium ions) were also investigated. The structure of the nanocomposites was studied by X-ray diffraction measurements. A detailed crystallization analysis was carried out by means of both isothermal and non-isothermal (melt and cold) measurements. All data were analyzed using the simple Avrami equation along with advanced isoconversional methods. The nucleation activity of the filler was investigated in every case. Lauritzen–Hoffman analysis was employed to isothermal data to estimate the nucleation parameters. From all these measurements it was found that the organo-clay I.30E induces the higher crystallization rates and lower activation energy and is more effective regarding the PET crystallization compared to the other types of organo-clays. The I.30E organo-clay nanocomposite exhibited also the higher immobilized amorphous fraction and the higher nucleation parameter Kg in the Lauritzen–Hoffman analysis. This is due to its better dispersion and exfoliation of the clay nanolayers into the PET matrix, compared to the other organoclays.

Effect of different types of organoclays and compatibilizers on the properties of polystyrene‐based nanocomposites

AbstractPolystyrene/organoclay nanocomposites were prepared by melt intercalation in the presence of elastomeric impact modifiers. Three different types of organically modified montmorillonites; Cloisite® 30B, 15A, and 25A, were used as reinforcement, whereas poly [styrene‐b‐(ethylene‐co‐butylene)‐b‐styrene] (SEBS‐g‐MA) and poly(ethylene‐b‐butyl acrylate‐b‐glycidyl methacrylate) (E‐BA‐GMA) elastomeric materials were introduced to act as impact modifier. Owing to its single aliphatic tail on its modifier and absence of hydroxyl groups, Cloisite® 25A displayed the best dispersion in the polystyrene matrix, and mostly delaminated silicate layers were obtained in the presence of SEBS‐g‐MA. This was attributed to the higher viscosity of SEBS‐g‐MA compared with both E‐BA‐GMA and poly(styrene‐co‐vinyloxazolin) (PS). In addition, the compatibility between SEBS‐g‐MA and PS was found to be better in comparison to the compatibility between E‐BA‐GMA and PS owing to the soluble part of SEBS‐g‐MA in PS. The clay particles were observed to be located mostly in the dispersed phase leading to larger elastomeric domains compared with binary PS/elastomer blends. The enlargement of the elastomeric domains resulted in higher impact strength values in the presence of organoclay. Good dispersion of Cloisite® 25A in PS/SEBS‐g‐MA blends enhanced the tensile properties of this nanocomposite produced. It was observed that the change in the strength and stiffness of the ternary nanocomposites mostly depend on the type of the elastomeric material. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013

Preparation and properties of melt-intercalated linear low density polyethylene/clay nanocomposite films prepared by blow extrusion

Linear low density polyethylene (LLDPE)/clay nanocomposite films with two different types of organoclays (Cloisite® 30B and Cloisite® 20A) were prepared using a melt blow extrusion method and their properties such as optical, tensile, water vapor and oxygen gas barrier, and antimicrobial activity were tested. Apparently the nanocomposite films are smooth, homogeneous, and flexible, but less transparent than the neat LLDPE film. XRD result indicated slightly intercalated nanostructures were formed with both organoclays. Though oxygen barrier properties improved after formation of the nanocomposite, the tensile strength (TS) and water vapor permeability (WVP) were not improved in the nanocomposite films. This is probably due to the lower compatibility between nonpolar, hydrophobic LLDPE polymer matrix and clay nanoparticles. Antimicrobial test showed the LLDPE/Cloisite® 30B nanocomposite film had a bacteriostatic activity against Gram-positive bacteria, Listeria monocytogenes.

Organoclay localization in polyamide 6/ethylene-butene copolymer grafted maleic anhydride blends: the effect of different types of organoclay

Localization of organoclays between two phases of polyamide 6 (PA6)/maleic anhydride grafted ethylene-butene copolymer (EB-g-MAH) blends, prepared via melt mixing, was investigated as a function of organoclay type. Cloisite 30B, Cloisite 20A and Cloisite 15A were used as different types of organoclay. The influence of different blend compositions and clay contents were also studied. Contact angle measurements have been applied to determine surface tension of components and then to calculate the wetting coefficient which is a useful parameter for prediction of the organoclay location. In general, all organoclays were found to locate in the more hydrophilic polyamide 6 phase. However, for Cloisite 20A and Cloisite 15A transmission electron microscopy (TEM) observations revealed some organoclay layers in the EB-g-MAH phase. Phase structure and nanocomposite morphology were evaluated using scanning and transmission electron microscopy and small angle X-ray scattering (SAXS). Results indicated the formation of an exfoliated or an intercalated morphology in different samples. Dynamic-mechanical thermal analysis and thermal gravimetric analysis were used as an experimental probe to confirm the location of nanoclays predicted via wetting coefficient. The shifting of glass transition temperature for PA6 phase confirmed that nanoclays are more distributed in this phase.

Preparation, characterization, and application of NR/SBR/Organoclay nanocomposites in the tire industry

AbstractThe natural rubber/styrene butadiene rubber/organoclay (NR/SBR/organoclay) nanocomposites were successfully prepared with different types of organoclay by direct compounding. The optimal type of organoclay was selected by the mechanical properties characterization of the NR/SBR/organoclay composites. The series of NR/SBR/organoclay (the optimal organoclay) nanocomposites were prepared with various organoclay contents loading from 1.0 to 7.0 parts per hundreds of rubber (phr). The nearly completely exfoliated organoclay nanocomposites with uniform dispersion were confirmed by transmission electron microscopy (TEM) and X‐ray diffraction (XRD). The results of mechanical properties measurement showed that the tensile strength, tensile modulus, and tear strength were improved significantly when the organoclay content was less than 5.0 phr. The tensile strength and the tear strength of the nanocomposite with only 3.0 phr organoclay were improved by 92.8% and 63.4%, respectively. It showed organoclay has excellent reinforcement effect with low content. The reduction of the score and cure times of the composites indicated that the organoclay acted as accelerator in the process of vulcanization. The incorporation of a small amount of organoclay greatly improved the swelling behavior and thermal stability, which was attributed to the good barrier properties of the dispersed organoclay layers. The outstanding performance of co‐reinforcement system with organoclay in the tire formulation showed that the organoclay had a good application prospect in the tire industry, especially for the improvement of abrasion resistance and the reduction of production cost. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2011

Comparative study of nanocomposites of polyolefin compatibilizers containing kaolinite and montmorillonite organoclays

AbstractThis work studied the morphology and physical properties of nanocomposites of different ethylene copolymers and functionalized polyethylenes with two different types of organoclays, to assess the potential application of these fillers as reinforcing components in the design of polyethylene and other polyolefinic based nanocomposites with enhanced properties. A polyethylene‐grafted‐maleic anhydride (PEMA), a poly(ethylene‐co‐acrylic acid), a poly(ethylene‐co‐vinyl acetate), and an ionomer of poly(ethylene‐co‐methacrylic acid) containing a small fraction of polyamide 6 were used to prepare nanocomposites by melt compounding in internal mixer. Two different types of commercial clays were used to obtain nanocomposites with the same organoclay content (5 wt %), i.e., an organomodified montmorillonite and an organomodified kaolinite. The morphology was evaluated by wide angle X‐ray scattering, scanning electron microscopy, transmission electron microscopy, and optical microscopy. The thermal, mechanical and barrier properties were evaluated by differential scanning calorimetry and thermogravimetric analysis, tensile tests and oxygen transmission rate experiments, respectively. From the results, it was seen that PEMA and the ionomer are the best polymer matrices to disperse both organoclays under the conditions applied. Kaolinite and montmorillonite appeared to be dispersed in the nanorange, however, higher aspect ratio was observed for montmorillonite. The best improvements in thermal degradation and in mechanical reinforcement were shown for organomodified kaolinite nanocomposites. But the best improvements in thermo‐oxidative degradation and in oxygen barrier were seen for the nanocomposites with organomodified montmorillonite. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010

Microcellular Foaming of Polypropylene/Clay Nanocomposites with Supercritical Carbon Dioxide

The solid-state foaming of two series of polypropylene (PP)/clay nanocomposites based on two different types of organoclays were studied. The wide-angle X-ray diffraction results showed that a supercritical carbon dioxide (scCO 2) saturation process could lead to the further exfoliation of clay when the initial interlayer spacing was larger enough. It was found that the incorporation of clays exerted significant impacts on cell nucleation and growth and the effect of clays was determined by their dispersion state. However, the influence of clay on the foaming of the PP/clay nanocomposites became marginal at a higher saturation pressure and a lower foaming temperature.

Rheological studies of uncured epoxy–organoclay nanocomposite coatings

AbstractWe investigated the influence of loading two different types of organoclay on the linear viscoelastic properties of an uncured epoxy nanocomposite coating. Meanwhile, the effect of sonication in the dispersion process on the characteristics of nanocomposite has been studied. To achieve fully dispersed structures of clay-epoxy, we applied high shear mixing and high-intensity ultrasound during the synthesis of clay-epoxy nanocomposites.The flow properties of the compositions with clay loadings more than 4 wt% of low CEC quaternary ammonium modified clay, as analyzed by rheomechanical spectroscopy (RMS), showed a solid-like behavior. While the neat resin system exhibited Newtonian flow, some nanodispersed coatings exhibited pseudo plastic flow behavior, typical of polymeric fluids such as gels and pastes. With varying the type of the clay the resultant coatings exhibited a storage modulus ranging from 0.01 to over 400 Pa and a loss modulus ranging from 4 to over 200 Pa. Moreover, the complex viscosity was ranging from 12 to 1100 Pas as the clay loading increased from 0 to 8wt %. The strong increase in modulus of one type of the clays was due to the mainly intercalated and dispersed silicate platelets. The increase rate in storage modulus of these compositions decreased at higher organoclay loadings and was not linear. These results can lead to the prediction of film formation properties and application conditions of these nanocomposite coatings

Preparation and cure behavior of organoclay‐modified allyl‐functional benzoxazine resin and the properties of their nanocomposites

AbstractA new type of polybenzoxazine‐clay nanocomposites were prepared by the in‐situ polymerization of allyl‐functional benzoxazine monomer, bis(3‐allyl‐3,4‐dihydro‐2H‐1,3‐benzoxazinyl)isopropane (B‐ala), in the presence of two different types of organoclay, allyldimethylstearylammonium‐montmorillonite and propyldimethylstearylammonium‐montmorillonite. The organoclays were mixed with molten B‐ala, followed by pouring into glass mold and then gradual curing up to 250°C. DSC and IR were used to follow the cure behavior of B‐ala in the presence of organoclay, indicating that organoclays catalyzed the ring opening of cyclic benzoxazine structure. The XRD of the nanocomposites showed featureless patterns, suggesting the exfoliation of the organoclay into the matrix. The viscoelastic properties of the hybrids showed that the glass transition temperatures (Tg) of the nanocomposites shifted to lower temperature in the presence of small amount of organoclay, but Tg started to increase with the increase of the organoclay content. This result suggests that, in the presence of organoclay, the curing reaction of ally and benzoxazine occurred in a different way, resulting in a different network structure. However, the presence of dispersed layered silicates into the matrix enhanced the thermal stability over the neat thermoset resin. POLYM. COMPOS., 2008. © 2008 Society of Plastics Engineers

Epoxy-organoclay nanocomposites: morphology, moisture absorption behavior and thermo-mechanical properties

The morphology and moisture barrier characteristics are studied of epoxy-based nanocomposites reinforced with layered silicates. Two different types of organoclay, including the quaternary alkylamine modified montmorillonite (KH-MT) and the octadecylamine modified montmorillonite (I30P), were studied. The X-ray diffraction (XRD) and transmission electron microscopy (TEM) indicate that the I30P system exhibited a large increase in interlayer d -spacing from 3.39 mm to over 8 nm during the curing process, whereas the KH-MT system showed negligible changes in reflection angle and d -spacing, with the final interlayer distance of 3.39 nm after cure. The moisture absorption behaviour was different for different organoclays: the moisture absorption rate was similar for the neat polymer and the KH-MT system, which could be fitted to Fick's second law. The moisture absorption rate of the I30P system was much lower than the two systems, which was predicted using a non-Fickian model based on the ID Langmuirian solution. The deviation from the Fickian diffusion for the latter system is associated with exfoliated morphology and more uniform dispersion of clay particles, which altered the diffusion path of water molecules in the nanocomposite. The moisture diffusivity of nanocomposites in general decreased with increasing clay content, the reduction being more pronounced for the I30P system. The normalized permeability also showed a systematic degradation with increasing clay content, which agrees well with the prediction based on the tortuous path model.

Nanocomposites of poly(trimethylene terephthalate) with various organoclays: morphology, mechanical and thermal properties

Three types of organoclay, 12C-MMT, 18C-MMT, and DK2-MMT, have been used to prepare poly(trimethylene terephthalate)(PTT)/organoclay nanocomposites via melt blending using a co-rotating twin screw extruder. The effect of different types of organoclays on morphology, thermal stability, static and dynamic mechanical properties was examined. The results of wide angle X-ray diffraction (WAXD) and transmission electron microscopy (TEM) suggest that different interaction between the different organoclays and the PTT matrix lead to different morphologies (intercalation or exfoliation) of the three types of nanocomposites. Thermogravimetric analysis (TGA) shows that the nanocomposites are more thermally stable than the neat PTT. Moreover, mechanical properties are improved for all the nanocomposites. Dynamic mechanical analysis (DMA) shows that nano-sized organoclay dispersed in PTT matrix enhances the storage modulus of the material and causes change of the α relaxation of PTT.