Papers by Keyword: Bentonite Clay

Abstract: Preparation, characterization, and machine learning prediction of characteristics of acid-treated organobentonite-based highly porous foams via polymerized high internal phase emulsion were reported in this work. The effect of acid-treated organobentonite (AC-BTN) as an inorganic filler on the properties of poly(DVB)HIPE porous foam was experimentally investigated. Incorporating AC-BTN into the continuous phase of the high internal phase emulsion would improve thermal and mechanical properties and also increase the surface area of the resulting materials when compared to the unfilled poly(DVB)HIPE foam. Various amounts of AC-BTN, i.e., 0, 1, 3, 5, 7, and 10 wt.% of AC-BTN, were incorporated into the continuous phase to enhance the properties of poly(DVB)HIPE foam. The surface area and the degradation temperatures (T_d) for the series of poly(DVB)HIPE foam filled with AC-BTN increased with increasing filler content from 0 to 10 wt.%. The maximum improvement of mechanical properties was found with the addition of 5 wt.% of AC-BTN into the continuous phase of poly(DVB)HIPE foam. Moreover, the adsorption of CO₂ gas by poly(DVB)HIPE foam filled with AC-BTN was found to increase as well. It has been demonstrated in this study that the adsorption of CO₂ by poly(DVB)HIPE foam filled with AC-BTN increased by 127% (from 0.00295 to 0.00670 mol/g) compared with neat poly(DVB)HIPE foam. Additionally, the machine learning (ML) method with a linear regression algorithm was employed for the characterization of poly(DVB)HIPE foam and the prediction of properties according to composite composition. Surface area, pore volume, T_d, compressive stress, and Young’s modulus were evaluated. The accuracy of prediction using a machine learning application with a linear regression model for properties of poly(DVB)HIPE foam filled with AC-BTN was also reported.

Abstract: Cellular concrete (known as foamed concrete) is a lightweight building material with low densities ranging from 900 kg/m³ to 1900 kg/m³, which can have potential applications in civil engineering practices. However, it is very weak in withstanding tensile loads which leads to cracks during shrinkage in the drying stage. Therefore, six different groups of cellular concrete are prepared for a possible application in grouting underneath the foundations to achieve a minimum compressive strength of 2000 psi (13.79 MPa) as per ASTM C476, and for soil nail grout with a minimum compressive strength of 3000 psi (20.86 MPa) as per ASTM C109 at 28 days. Furthermore, these mixtures are undergoing laboratory testing for pushout (using steel cylinders with varied diamters and thickneses) and pullout tests as the subsequent part of this project. All groups contain 0.34 water-to-cement ratio, same size and amounts of sands and superplasticizer (SP). The first group included four control mixes without bentonite and polypropylene fiber (PPF) additives with varied foam content (C1-F1,F2,F3,F4). The remaining groups consist of 17 different mixes blended with either one or both additives. The content effect of foam agent, bentonite clay, and PPF as additives on the density and compressive and flexural strengths of cellular concrete are investigated in this study. The results revealed that the introduction of bentonite and/or PPF in cellular concrete mixtures increased the density and strength. The results revealed that low dry densities (less than 1900 kg/m³) of blended cellular concrete mixtures can reach high compressive strength of 24.37 MPa with 4.74 MPa flexural strength that make them feasible for geotechnical and structural engineering applications.

Abstract: In this work were studied the properties of moulding bentonite clay calcined at different temperatures and the properties of moulding sand-clay mixtures based on these clays.

Abstract: In this work, were obtained nanocomposite membranes polyamide66/Paraíba bentonite clay, treated with a quaternary ammonium salt in order to make it organophilic. The membranes were prepared as thin films using the technique of phase inversion from the nanocomposites obtained by solution. The membranes were characterized by X-ray diffraction (XRD), differential scanning calorimetry (DSC), thermogravimetry (TG) and scanning electron microscopy (SEM). By means of X-ray diffractogram, it was revealed that the membranes remained organically treated clay presented exfoliated and/or partially exfoliated structure. From curves of DSC and TG, it was observed that membrane of PA66 with 3% w/w of with treatment clay showed higher thermal stability compared with the same content of clay without treatment. From the SEM photomicrographs, there was a selective layer (skin filter) on top and one porous layer at the bottom of all membranes studied. Moreover, it was verified that the presence of clay provided a significant structural modification in the membranes of polymer nanocomposites.

Abstract: The bentonite clay fillers are mostly used for the development of nanocomposites, due to having characteristics which provide to obtain in nanometric particles. The bentonite clay was treated with an ammonium quaternary salt to modify it to organophilic clay. The polymeric membranes and nanocomposites were prepared using the phase inversion technique. The bentonite and organophilic clays were characterized by X-ray fluorescence (XRF), X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FTIR). The membranes were characterized by XRD. The results of XRF, XRD and FTIR confirmed the presence of quaternary ammonium salt in the organoclay structure. The XRD diffraction patterns of nanocomposites membrane showed exfoliated and/or partially exfoliated structure. According to the obtained results, it could be seen that the treatment performed on the surface of the clay was quite promising and efficient to be added as nanofillers on polymeric membranes.

Abstract: Recent advances in biodegradable polymers have attracted a great interest not only in traditional areas such as biomedical and pharmaceutical industry, but also in packaging applications, articles and injected membranes. The aim of this work was to produce bio-nanocomposites poly (lactic acid) - PLA with bentonite clay. The bio-nanocomposites were produced by melt intercalation with incorporation of 1 to 3 wt% of organoclay. The degree of dispersion of clays in the polymer, and consequently the structure of bio-nanocomposites produced was evaluated by X-ray diffraction (XRD), and the thermal properties were studied by differential scanning calorimetry (DSC). XRD results indicated the formation of intercalated structures. It was observed the appearance of crystalline melting double peaks in bio-nanocomposites PLA.

Abstract: In this study bionanocomposites were prepared from biodegradable polymer matrices such as poly (lactic acid) (PLA) and PBAT/PLA blend commercially known as Ecovio^®, with abundant smectite clays in Paraíba and modified (OMMT) with Praepagen quaternary ammonium salt. Systems with PLA and with the blends of PBAT/PLA were prepared with addition of bentonite clay at a concentration of 3wt.%. in a twin screw corrotational extruder. The systems containing PLA/OMMT and blend of PBAT/PLA/OMMT were characterized by X-ray diffraction (XRD) and Heat Deflection Temperature (HDT). From the diffractograms of bionanocomposites PLA/OMMT and PBAT/PLA/ OMMT it was observed a probably microcomposite structure. It was also observed that the HDT of PBA/PLA/OMMT and the blend of PBAT/PLA bionanocomposites was lower in relation to pure PLA and its PLA/OMMT bionanocomposite.

Abstract: The nanocomposites are hybrid materials where at least one of the components has nanometric dimensions and in the same way as traditional composites are formed, one of the components is the matrix in which nanoparticles are dispersed. One of the possibilities of applications of nanocomposites is to obtain polymer films for applications in the barrier, or separation promoted by the dispersion of the clay lamellae. In this work, nanocomposites of nylon 6/bentonite clay were obtained by melt intercalation. The used clay was the Brasgel PA, and quaternary ammonium salt was Praepagen-HY, used in organophilization of the clay. By XRD, it was observed the disappearance of the characteristic peak of clay, and this can be facilitate the possible exfoliation of clay in the produced films from the nanocomposite. By SEM, it was observed, an apparently dense layer with no pores.

Abstract: Membranes can be defined as polymer film that acts as a semipermeable barrier to filtration in a molecular scale, separating two phases. In this work, microporous membranes were obtained from hybrid organic/inorganic polyamide66 (PA66) and clay mineral from Paraíba State, treated with a quaternary ammonium salt in order to make it organophilic. The membranes in the form of thin films were prepared by immersion-precipitation technique from the nanocomposites obtained by solution, with a pre-determined reaction time of 2 h, with characteristics suitable to be used in microfiltration process for separation of the oil present in water. Samples of natural and organophilic clay were characterized by X-ray fluorescence (XRF) and Fourier transform infrared spectroscopy (FTIR). Meanwhile, the membranes were characterized by differential scanning calorimetry (DSC) and scanning electron microscopy (SEM). The results of FRX and FTIR confirmed the presence of quaternary ammonium salt in the clay structure after treatment with organic salt. Through DSC analysis it was observed almost no change in the melting temperature of the pure polyamide66 membranes. By SEM, it was revealed an asymmetric morphology consisting of a skin layer and a porous sublayer, showing the pore size distribution appropriated to water-oil separation.

Abstract: The development of nanocomposites polymer matrix with clay from Brazil has been naturally abundant and low cost alternative. In this study, we obtained nanocomposites polyamide66 (PA66) with 1% and 5% of bentonite clay from Brazil, to be used as microporous organic/inorganic hybrid membranes. The clay was treated with a quaternary ammonium salt in order to make it organophilic. The membranes in the form of thin films were prepared using the technique of immersion-precipitation of solution from the nanocomposites. Treated clay and untreated clay were characterized by X-ray diffraction (XRD) and Thermogravimetry (TG). The membranes were characterized by TG and XRD. The result of XRD showed the presence of quaternary ammonium salt in the structure of clay, after organophilization. For TG, we observed that the treated clay showed higher thermal stability when compared to untreated clay. For TG, we observed that in general the membranes of PA66 with treated clay, present decomposition temperature higher when compared with untreated clay, thus revealing a greater thermal stability of membranes PA66 with treated clay. Through the X-rays patterns, it was found that membranes with 1% of nanoclay present exfoliated structure and can therefore be applied as microporous membranes.