Effect of sonication conditions: Solvent, time, temperature and reactor type on the preparation of micron sized vermiculite particles

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 5h 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 [001]; 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.

Exploring the Effect of Particle Concentration and Irradiation Time in the Synthesis of Barium Strontium Titanate (BST) Ba(1-X)SrxTiO3 (X:0-1) Nanoparticles by High Power Ultrasonic Irradiation

“…This indicated that the reduction of mean particle sizes by ultrasonic irradiation is less effective in irradiated media with high particle concentrations. Similar results were also reported, showing that higher particle concentrations enhanced the viscosity of irradiated media and hindered the cavitation effect (Ali et al, 2014).…”

Stiffening mechanisms in vermiculite–amorphous polyamide bio-nanocomposites

“…They were conditioned at 25 °C and 50% RH for at least 48 h before testing. Tensile tests were performed according to to a significant decrease of the particle sizes as observed by others [18,25]. The majority of the particles were irregular, but on the whole, they were convex shaped two-dimensional flakes.…”

“…Vermiculite can also be exfoliated by treatment with H 2 O 2 [18,19]. Exfoliation into submicronic and even nanoflakes can be accomplished by subsequent sonication using high power ultrasound [18,[21][22][23][24][25].…”

Room temperature and high temperature sealing properties and compression properties of compressive gaskets made of micrometric vermiculite particles

“…The vermiculite (0.4 mm mean diameter size, weighted amount of 0.55 g or 3.85 g) was sonicated at room temperature in 55 mL hydrogen peroxide (35%) in a "Rosett" type glass double-jacketed reactor cooled at 25°C by circulation of a cryogenic fluid, using a Sonotrode (20 kHz, 350 W, Ti ultrasonic probe, Sonics and Materials, 43 mm amplitude, 56 W acoustic power) in order to produce small particles (Nguyen et al, 2013;Ali et al, 2014;Nguyen et al, 2014). The solid/liquid (S/L) ratio and the sonication time were varied in order to modify the particle size distributions.…”