The Experts below are selected from a list of 288 Experts worldwide ranked by ideXlab platform
Luis A Perezmaqueda - One of the best experts on this subject based on the ideXlab platform.
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sonication as a tool for preparing nanometric Vermiculite particles
Nanotechnology, 2002Co-Authors: J L Perezrodriguez, F Carrera, J Poyato, Luis A PerezmaquedaAbstract:We have studied the effect of ultrasound on two different natural macroscopic Vermiculite samples from Ojen and Santa Olalla (Spain). We describe the conditions for the preparation of nanometric particles by sonochemistry. Sonication produces not only a delamination effect in the [00l] direction, but also a breaking of layers in the other directions, while the crystalline character is retained. Some differences have been observed in the behaviour of both Vermiculites. Thus, the Santa Olalla sample suffers an important decrease in crystallite size with up to 30 h treatment time; longer treatment times do not produce any effect on crystallite size. On the other hand, the Ojen sample suffers a decrease in its crystallite size with up to 80 h treatment time, remaining unchanged for longer treatments. The crystallite sizes in the [00l] direction are much smaller for the Ojen sample than for the Santa Olalla sample. In addition, the Santa Olalla sample maintains the typical laminar shape after sonication, while the Ojen sample suffers a morphological change. The different behaviours seem to be related to the different compositions and, therefore, the different layer charges of both Vermiculite samples.
Syed Sakhawat Shah - One of the best experts on this subject based on the ideXlab platform.
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effect of sonication conditions solvent time temperature and reactor type on the preparation of micron sized Vermiculite particles
Ultrasonics Sonochemistry, 2014Co-Authors: Laurence Reinert, Jeanmarc Leveque, Laurent Duclaux, Fabrice Muller, Shaukat Saeed, Syed Sakhawat ShahAbstract:Abstract The effects of temperature, time, solvent and sonication conditions under air and Argon are described for the preparation of micron and sub-micron sized Vermiculite particles in a double-jacketed Rosett-type or cylindrical reactor. The resulting materials were characterized via X-ray powder diffraction (XRD), Field Emission Scanning Electron Microscopy (FE-SEM), Fourier Transform Infrared (FTIR) Spectroscopy, BET surface area analysis, chemical analysis (elemental analysis), Thermogravimetry analysis (TGA) and Laser Granulometry. The sonicated Vermiculites displayed modified particle morphologies and reduced sizes (observed by scanning electron microscopy and laser granulometry). Under the conditions used in this work, sub-micron sized particles were obtained after 5 h of sonication, whereas longer times promoted aggregation again. Laser granulometry data revealed also that the smallest particles were obtained at high temperature while it is generally accepted that the mechanical effects of ultrasound are optimum at low temperatures according to physical/chemical properties of the used solvent. X-ray diffraction results indicated a reduction of the crystallite size along the basal direction [0 0 1]; but structural changes were not observed. Sonication at different conditions also led to surface modifications of the Vermiculite particles brought out by BET surface measurements and Infrared Spectroscopy. The results indicated clearly that the efficiency of ultrasound irradiation was significantly affected by different parameters such as temperature, solvent, type of gas and reactor type.
B. Smetana - One of the best experts on this subject based on the ideXlab platform.
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Role of Vermiculite and zirconium–Vermiculite on the formation of zircon–cordierite nanocomposites
Applied Clay Science, 2013Co-Authors: Marta Valášková, J. Tokarský, M. Hundáková, J. Zdrálková, B. SmetanaAbstract:Abstract The Zr 4 + –Vermiculites were studied in their new role of the zircon precursor in the clay minerals mixtures which were prepared for firing of the zircon–cordierite nanocomposites. Currently there is a lack of data available about the structure of Zr 4 + –Vermiculites, on which this study was performed. The modeling of the arrangement of interlayer material in the Zr 4 + –Vermiculite led to new findings that water molecules are attracted more strongly by Mg 2 + cations than by Zr-tetrameric cations, and that both the tetrameric cations [Zr 4 (OH) 14 (H 2 O) 10 ] 2 + and [Zr 4 (OH) 8 (H 2 O) 16 ] 8 + may be present in the interlayer space of the Zr 4 + –Vermiculites. Vermiculites from two different localities Czech Republic (Verm1) and from Brazil (Verm2) were intercalated using the zirconyl chloride (ZrOCl 2 –30% solution in HCl) and the prepared Zr 4 + –Vermiculites were designated as Zr 4 + –Verm1 and Zr 4 + –Verm2, respectively. Influence of the Zr 4 + –Verm1 and Zr 4 + –Verm2 in the mixtures of clay minerals on the properties of zircon–cordierite nanocomposites were investigated by their comparison with the properties of the zircon–cordierite nanocomposites, which were prepared using saturation of the clay minerals mixtures containing Verm1 and Verm2 with the zirconyl chloride (ZrOCl 2 –30% solution in HCl). The zircon–cordierite nanocomposites fired from the clay mineral mixtures containing Zr 4 + –Verm1 and Zr 4 + –Verm2 showed a maximum porosity of P = 58 and 60%, skeletal density SD = 3.2 and 3.6, and the smallest pores with a median pores diameter MDP = 18 and 15 μm, respectively, in comparison with the zircon–cordierite nanocomposites fired from the clay mineral mixtures containing Verm1 and Verm2 and saturated with zirconyl chloride solution. The type of Vermiculite Verm1 or Verm2 in the clay mineral mixtures did not affect the contents of the crystalline mineral phases in cordierite and zircon–cordierite nanocomposites.
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Role of Vermiculite and zirconium–Vermiculite on the formation of zircon–cordierite nanocomposites
Applied Clay Science, 2013Co-Authors: M. Valášková, J. Tokarský, M. Hundáková, J. Zdrálková, B. SmetanaAbstract:The Zr4 +–Vermiculites were studied in their new role of the zircon precursor in the clay minerals mixtures which were prepared for firing of the zircon–cordierite nanocomposites. Currently there is a lack of data available about the structure of Zr4 +–Vermiculites, on which this study was performed. The modeling of the arrangement of interlayer material in the Zr4 +–Vermiculite led to new findings that water molecules are attracted more strongly by Mg2 + cations than by Zr-tetrameric cations, and that both the tetrameric cations [Zr4(OH)14(H2O)10]2 + and [Zr4(OH)8(H2O)16]8 + may be present in the interlayer space of the Zr4 +–Vermiculites. Vermiculites from two different localities Czech Republic (Verm1) and from Brazil (Verm2) were intercalated using the zirconyl chloride (ZrOCl2–30% solution in HCl) and the prepared Zr4 +–Vermiculites were designated as Zr4 +–Verm1 and Zr4 +–Verm2, respectively. Influence of the Zr4 +–Verm1 and Zr4 +–Verm2 in the mixtures of clay minerals on the properties of zircon–cordierite nanocomposites were investigated by their comparison with the properties of the zircon–cordierite nanocomposites, which were prepared using saturation of the clay minerals mixtures containing Verm1 and Verm2 with the zirconyl chloride (ZrOCl2–30% solution in HCl). The zircon–cordierite nanocomposites fired from the clay mineral mixtures containing Zr4 +–Verm1 and Zr4 +–Verm2 showed a maximum porosity of P = 58 and 60%, skeletal density SD = 3.2 and 3.6, and the smallest pores with a median pores diameter MDP = 18 and 15 μm, respectively, in comparison with the zircon–cordierite nanocomposites fired from the clay mineral mixtures containing Verm1 and Verm2 and saturated with zirconyl chloride solution. The type of Vermiculite Verm1 or Verm2 in the clay mineral mixtures did not affect the contents of the crystalline mineral phases in cordierite and zircon–cordierite nanocomposites.Web of Science75-7610810
J L Perezrodriguez - One of the best experts on this subject based on the ideXlab platform.
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sonication as a tool for preparing nanometric Vermiculite particles
Nanotechnology, 2002Co-Authors: J L Perezrodriguez, F Carrera, J Poyato, Luis A PerezmaquedaAbstract:We have studied the effect of ultrasound on two different natural macroscopic Vermiculite samples from Ojen and Santa Olalla (Spain). We describe the conditions for the preparation of nanometric particles by sonochemistry. Sonication produces not only a delamination effect in the [00l] direction, but also a breaking of layers in the other directions, while the crystalline character is retained. Some differences have been observed in the behaviour of both Vermiculites. Thus, the Santa Olalla sample suffers an important decrease in crystallite size with up to 30 h treatment time; longer treatment times do not produce any effect on crystallite size. On the other hand, the Ojen sample suffers a decrease in its crystallite size with up to 80 h treatment time, remaining unchanged for longer treatments. The crystallite sizes in the [00l] direction are much smaller for the Ojen sample than for the Santa Olalla sample. In addition, the Santa Olalla sample maintains the typical laminar shape after sonication, while the Ojen sample suffers a morphological change. The different behaviours seem to be related to the different compositions and, therefore, the different layer charges of both Vermiculite samples.
M. Hundáková - One of the best experts on this subject based on the ideXlab platform.
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Vermiculite in polycaprolactone films prepared with the used of ultrasound
Materials Today: Proceedings, 2020Co-Authors: Karla Čech Barabaszová, M. Hundáková, Sylva Holešová, Vojtěch MohylaAbstract:Abstract The morphologic and phase properties of polycaprolactone/Vermiculite films prepared by ultrasound intensive mixing were evaluated. Two types of the mechanically processed natural Mg - Vermiculite (ball and jet milled) with different particle size and morphology and trichlormethan as an exfoliation agent were used. The polycaprolactone/Vermiculite films were prepared using 1, 3 and 5 wt% of Vermiculite nanofiller and were evaluated by the following methods: 3D optical confocal microscope, scanning electron microscopy, X-ray diffraction and Fourier transforms infrared spectroscopy. The positive effect of Vermiculite particles on homogeneous distribution in PCL matrix was shown. The hydrophilic surfaces of each PCL film with the water contact angle in interval value of 62–74° were measured.
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Role of Vermiculite and zirconium–Vermiculite on the formation of zircon–cordierite nanocomposites
Applied Clay Science, 2013Co-Authors: Marta Valášková, J. Tokarský, M. Hundáková, J. Zdrálková, B. SmetanaAbstract:Abstract The Zr 4 + –Vermiculites were studied in their new role of the zircon precursor in the clay minerals mixtures which were prepared for firing of the zircon–cordierite nanocomposites. Currently there is a lack of data available about the structure of Zr 4 + –Vermiculites, on which this study was performed. The modeling of the arrangement of interlayer material in the Zr 4 + –Vermiculite led to new findings that water molecules are attracted more strongly by Mg 2 + cations than by Zr-tetrameric cations, and that both the tetrameric cations [Zr 4 (OH) 14 (H 2 O) 10 ] 2 + and [Zr 4 (OH) 8 (H 2 O) 16 ] 8 + may be present in the interlayer space of the Zr 4 + –Vermiculites. Vermiculites from two different localities Czech Republic (Verm1) and from Brazil (Verm2) were intercalated using the zirconyl chloride (ZrOCl 2 –30% solution in HCl) and the prepared Zr 4 + –Vermiculites were designated as Zr 4 + –Verm1 and Zr 4 + –Verm2, respectively. Influence of the Zr 4 + –Verm1 and Zr 4 + –Verm2 in the mixtures of clay minerals on the properties of zircon–cordierite nanocomposites were investigated by their comparison with the properties of the zircon–cordierite nanocomposites, which were prepared using saturation of the clay minerals mixtures containing Verm1 and Verm2 with the zirconyl chloride (ZrOCl 2 –30% solution in HCl). The zircon–cordierite nanocomposites fired from the clay mineral mixtures containing Zr 4 + –Verm1 and Zr 4 + –Verm2 showed a maximum porosity of P = 58 and 60%, skeletal density SD = 3.2 and 3.6, and the smallest pores with a median pores diameter MDP = 18 and 15 μm, respectively, in comparison with the zircon–cordierite nanocomposites fired from the clay mineral mixtures containing Verm1 and Verm2 and saturated with zirconyl chloride solution. The type of Vermiculite Verm1 or Verm2 in the clay mineral mixtures did not affect the contents of the crystalline mineral phases in cordierite and zircon–cordierite nanocomposites.
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New aspects on Vermiculite filler in polyethylene
Applied Clay Science, 2013Co-Authors: Marta Valášková, J. Tokarský, M. Hundáková, Karla Čech Barabaszová, Vlastimil Matějka, Erich Pazdziora, Dusan KimmerAbstract:Abstract The Vermiculite from Brazil (fy Grena in Czech Republic) was used as clay mineral nanofiller to polyethylene. Two Vermiculite size fractions were prepared in a planetary ball mill and in the jet mill. The Vermiculite/polyethylene nanocomposites were prepared with 7 mass% and 3.5 mass% of Vermiculite nanofillers using melt compounding procedure without additives. The characterization of Vermiculite nanofillers and their corresponding clay polymer nanocomposites (CPN) was made based on the results obtained using the X-ray powder diffraction, particle size distribution and specific surface area measurements. The surfaces of CPN plates were studied using atomic force microscopy. The arrangement of the PE chains near the Vermiculite structure was investigated by molecular modeling. Finding that the CPN have an effect on bacterial growth was confirmed by long-term evaluation of the living/deceased Enterococcus faecalis bacteria on the surface plates of the CPN.
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Role of Vermiculite and zirconium–Vermiculite on the formation of zircon–cordierite nanocomposites
Applied Clay Science, 2013Co-Authors: M. Valášková, J. Tokarský, M. Hundáková, J. Zdrálková, B. SmetanaAbstract:The Zr4 +–Vermiculites were studied in their new role of the zircon precursor in the clay minerals mixtures which were prepared for firing of the zircon–cordierite nanocomposites. Currently there is a lack of data available about the structure of Zr4 +–Vermiculites, on which this study was performed. The modeling of the arrangement of interlayer material in the Zr4 +–Vermiculite led to new findings that water molecules are attracted more strongly by Mg2 + cations than by Zr-tetrameric cations, and that both the tetrameric cations [Zr4(OH)14(H2O)10]2 + and [Zr4(OH)8(H2O)16]8 + may be present in the interlayer space of the Zr4 +–Vermiculites. Vermiculites from two different localities Czech Republic (Verm1) and from Brazil (Verm2) were intercalated using the zirconyl chloride (ZrOCl2–30% solution in HCl) and the prepared Zr4 +–Vermiculites were designated as Zr4 +–Verm1 and Zr4 +–Verm2, respectively. Influence of the Zr4 +–Verm1 and Zr4 +–Verm2 in the mixtures of clay minerals on the properties of zircon–cordierite nanocomposites were investigated by their comparison with the properties of the zircon–cordierite nanocomposites, which were prepared using saturation of the clay minerals mixtures containing Verm1 and Verm2 with the zirconyl chloride (ZrOCl2–30% solution in HCl). The zircon–cordierite nanocomposites fired from the clay mineral mixtures containing Zr4 +–Verm1 and Zr4 +–Verm2 showed a maximum porosity of P = 58 and 60%, skeletal density SD = 3.2 and 3.6, and the smallest pores with a median pores diameter MDP = 18 and 15 μm, respectively, in comparison with the zircon–cordierite nanocomposites fired from the clay mineral mixtures containing Verm1 and Verm2 and saturated with zirconyl chloride solution. The type of Vermiculite Verm1 or Verm2 in the clay mineral mixtures did not affect the contents of the crystalline mineral phases in cordierite and zircon–cordierite nanocomposites.Web of Science75-7610810
