Thermal analysis of the interaction between stearic acid and pyrophillite or talc. IR and DTA studies

Heller-Kallai, L.; Yariv, S.; Friedman, I.

doi:10.1007/bf01913890

Cited by 17 publications

(3 citation statements)

References 8 publications

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“…The boiling temperature of stearic acid (383 ºC), appears to correspond to the maximum point of the mentioned hump-shaped curve. These observations are comparable with those of Heller-Kallai et al [44]. The TGA analysis results suggest that stearic acid was bound to the surface of the anhydrous borax by a physical mechanism rather than chemical bonding, due to the fact that stearic SA coating caused only a change in mass.…”

Section: Discussionsupporting

confidence: 90%

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Characterization of surface properties of dry-coated anhydrous borax powders

Akpinar

2020

Journal of Boron

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Dry particle coating of anhydrous borax (ANB) powders with hydrophobic stearic acid (SA) in the planetary ball mill was investigated. Two process parameters, the amounts of modifier agent and the processing periods, were selected to investigate their effects on solubility, wettability, dispersibility, and hydration properties of ANB powders. Each of the process parameters, i.e., SA amounts (0.5, 1, and 2 wt%), and coating periods (30, 60, and 120 min), was set at three different levels. Structural changes in the dry-coated powders were characterised using X-ray diffraction (XRD) and photoelectron spectroscopy (XPS), Fouriertransform infrared spectroscopy (FT-IR), Scanning electron microscopy (SEM), and Differential thermal and thermogravimetric analysis (DTA-TG). A discrete coating at an efficiency of 68% was acquired with SA amount of 1 wt% at a coating period of 60 min, and, thus, resulted in a 31.4% decrease (from 40% to 8.6%) in water solubility of ANB. Moreover, this discrete SA coating made ANB more hydrophobic (99 o) and prevented its further hydration. Furthermore, FT-IR and XPS results indicated that SA is coated over the surface of ANB via physical adsorption rather than chemical bonding. Thus, the effective dry coating could be applied to obtain surface-coated ANB, which offers controlled solubility in water-based suspensions.

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Section: Discussionsupporting

confidence: 90%

“…The boiling temperature of stearic acid (383 ºC), corresponds to the maximum point of the mentioned hump-shaped curve. These observations are comparable with those of Heller-Kallai et al [44].…”

Section: Thermal Stabilities Of Surface-coated and Uncoated Anb Powderssupporting

confidence: 93%

Characterization of surface properties of dry-coated anhydrous borax powders

Akpinar

2020

Journal of Boron

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“…4,9 -11 The effects of grinding on clay minerals have been studied extensively, mainly for kaolinite, montmorillonite, and bentonite 12,13 because of their importance as industrial ceramic raw materials. Some attention has been devoted to other silicates, for instance, sepiolite, 14 talc, [15][16][17][18] or pyrophyllite. 19 -24 The grinding of kaolinite has been the subject of research for a long time.…”

Section: Introductionmentioning

confidence: 99%

Effects of Dry Grinding on the Structural Changes of Kaolinite Powders

Sánchez-Soto

Haro

Pérez‐Maqueda

et al. 2000

Journal of the American Ceramic Society

128

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The present study examined the effects of dry grinding, using ball-milling, on the structure of reference well-crystallized (KGa-1) and poorly crystallized (KGa-2) kaolinite powders from Georgia. Grinding produced a strong structural alteration, mainly along the c axis, resulting in disorder and total degradation of the crystal structure of the kaolinite and the formation of an amorphous product. The surface area increased with grinding time, mainly in KGa-2 (maximum value 50.27 m 2 /g), a result associated with particle-size reduction. These particles became more agglomerated with grinding, and the surface area decreased after 30 min, as confirmed by scanning electron microscopy and particle-size-distribution analysis. There was a limit to particle-size reduction with grinding time. When grinding time was increased, the original endothermic differential thermal analysis (DTA) effects of dehydroxylation in both samples shifted to lower temperatures, decreased in intensity, then disappeared completely after 120 min of grinding. The temperature of the characteristic first exothermic effect shifted slightly to lower temperatures with grinding, although the DTA effects did not increase with grinding time in either kaolinite sample, at least up to 325 min. The amorphous, mechanically activated kaolinite converted into low-crystalline mullite nuclei at a lower temperature than did the unground samples, as deduced by thermal and X-ray observations. This effect was especially important for the KGa-2 sample. Grinding did not seem to influence the formation of silicon-aluminum spinel from kaolinite. The present results may explain why ground kaolinite samples prepared via different routes-e.g., with differences in grinding-behave differently during high-temperature transformations, as reported in the related literature.

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Differential Thermal Analysis (DTA) in the Study of Thermal Reactions of Organo-Clay Complexes

Yariv

2003

Natural and Laboratory-Simulated Thermal Geochemical Processes

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Thermal analysis of the interaction between stearic acid and pyrophillite or talc. IR and DTA studies

Cited by 17 publications

References 8 publications

Characterization of surface properties of dry-coated anhydrous borax powders

Characterization of surface properties of dry-coated anhydrous borax powders

Effects of Dry Grinding on the Structural Changes of Kaolinite Powders

Differential Thermal Analysis (DTA) in the Study of Thermal Reactions of Organo-Clay Complexes

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