Surface treatment of clay minerals ? thermal stability, basal-plane spacing and surface coverage

Osman, Maged A.; Ploetze, Michael; Suter, Ulrich W.

doi:10.1039/b302331a

Cited by 96 publications

(89 citation statements)

References 39 publications

(66 reference statements)

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“…Taking also into account that the commercial D67G sample reveals a higher carbon content (corresponding to an excess of ammonium salt of about 8%, see Experimental), it was hypothesized the presence of free ammonium chloride in the commercial sample D67G. This was confirmed by exhaustive Soxhlet extraction with ethanol of commercial D67G sample (last raw of Table 2), that led to a reduction of the interlayer distance from 3.4 to 2.6 nm [11]. Linear correlation between interlayer height and surfactant salt content is consistent with previous investigation of organoclay with long chain quaternary alkyl surfactants [7a, 12].…”

Section: Characterization Of Ammonium Salts Organoclays and Ir/organmentioning

confidence: 60%

Thermal stability of ammonium salts as compatibilizers in polymer/layered silicate nanocomposites

et al. 2009

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Thermal stability of alkyl and arylalkyl quaternary ammonium cation (onium) in starting chloride salt, in organoclay obtained after exchange with montmorillonite (MMT) and after mixing of the organoclay with isoprene rubber was examined using conventional TGA and by mass spectrometry pyrolysis/GC-MS. Degradation was observed to occur at T ≥ 170 °C for organoclays and the main volatile compounds were identified as tertiary amines, chloroalkanes and alkenes. Mechanisms for their formation are proposed and the role of residual onium chloride and basic centers of layered silicate is discussed.

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Section: Characterization Of Ammonium Salts Organoclays and Ir/organmentioning

confidence: 60%

Thermal stability of ammonium salts as compatibilizers in polymer/layered silicate nanocomposites

et al. 2009

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“…[2,3] Both the degree of exchange (100% of the CEC) and the purity of the organic monolayer were monitored by Hi-Res thermogravimetric analysis (TGA) on a Q500 analyzer (TA Instruments, New Castle, DE). All measurements (50-900 8C) were carried out in an air stream under the same conditions.…”

Section: Clay Surface Treatmentmentioning

confidence: 99%

“…[14,20,21] The presence of excessive unreacted organic molecules in the OM has been reported to have detrimental effect on the thermal stability and properties of the composites. [2,[22][23][24] The ammonium head group of the surfactant is susceptible to degradation at the high compounding temperatures and the thermal stability of the organic coating is a serious concern. A decrease in d-spacing during compounding has been observed and attributed to the surfactant degradation.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Poly(propylene)‐Layered Silicate Nanocomposites: Gas Permeation Properties and Clay Exfoliation

Osman

Mittal

Suter

2007

Macro Chemistry & Physics

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To monitor the mineral surface coverage and energy, the inorganic cations of two clays (montmorillonite) with different surface area/cation have been exchanged by alkylammonium ions, carrying alkyl chains of different number and length. The prepared OMs were free of unreacted organic ions. With increasing length and number of the alkyl chains, an increase in the basal‐plane spacing (d‐spacing) of the OM was observed. The d‐spacing also increased with increasing CEC of the clay (decreasing available area/cation). The OMs were compounded with PP and their effect on the crystallinity and gas‐barrier properties of the polymer was investigated. The OM had no influence on the degree of crystallinity of PP under the processing conditions used. Oxygen permeation through the composites decreased, depending on the cross‐sectional area of the exchanged organic cation and the CEC of the clay. These parameters control the mineral surface coverage (consequently the surface energy) as well as the tilt angle of the alkyl chains to the mineral surface, and hence the d‐spacing. Increasing the length of the alkyl chains and their number per cation enhanced the d‐spacing, clay exfoliation, and the gas‐barrier properties of the composites. A mixed morphology, consisting of delaminated aluminosilicate layers and OM tactoids of varying thickness was observed but no intercalation took place. The oxygen permeation coefficient of the nanocomposites was found to be a non‐linear function of the volume fraction of the inorganic part of the OM.magnified image

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“…27 Al MAS NMR spectra were acquired at 117 a frequency of 104.26 MHz, using a pulse width of 0.92 μs (π/2 pulse length = 9.2 μs) and a 118 delay time of 0.1 s. 23 Na MAS NMR spectra were recorded at 105.84 MHz with pulse widths of 119 2.0 μs (π/2 pulse length=12.0 μs) and a delay time of 0.1 s. 29 7 acquired at a frequency of 79.49 MHz, using a pulse width of 2.7 μs (π/2 pulse length = 7.1 μs) 121 and a delay time of 3 s. investigate the structure and properties of the tetradecylammonium molecules adsorbed onto Na-129 Mica-n, the adsorbed amount of the organic cations are monitored by TG. 37,38,39 Table 1 shows 130 the content of water and surfactant obtained from the analysis of the TG curves, where the 131 amount of interlayer water is determined from the weight loss in the temperature range of 170 °C and the amount of the adsorbed tetradecylammonium molecules is determined from the 133 weight loss between 170 and 900 °C. 40 …”

Section: Introduction 31mentioning

confidence: 99%

Self-Assembling of Tetradecylammonium Chain on Swelling High Charge Micas (Na-Mica-3 and Na-Mica-2): Effect of Alkylammonium Concentration and Mica Layer Charge

et al. 2015

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A family of tetradecylammonium micas is synthesized using synthetic swelling micas with high layer charge (Na n Si 8−n Al n Mg 6 F 4 O 20 •XH 2 O, where n = 2 and 3) exchanged with tetradecylammonium cations. The molecular arrangement of the surfactant is elucidated on the basis of XRD patterns and DTA.The ordering conformation of the surfactant molecules into the interlayer space of micas is investigated by IR/FT, 13 C, 27 Al, and 29 Si MAS NMR. The structural arrangement of the tetradecylammonium cation in the interlayer space of highcharge micas is more sensitive to the effect of the mica layer charge at high concentration. The surfactant arrangement is found to follow the bilayer-paraffin model for all values of layer charge and surfactant concentration. However, at initial concentration below the mica CEC, a lateral monolayer is also observed. The amount of ordered conformation all-trans is directly proportional to the layer charge and surfactant concentration.

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Surface treatment of clay minerals ? thermal stability, basal-plane spacing and surface coverage

Cited by 96 publications

References 39 publications

Thermal stability of ammonium salts as compatibilizers in polymer/layered silicate nanocomposites

Thermal stability of ammonium salts as compatibilizers in polymer/layered silicate nanocomposites

Poly(propylene)‐Layered Silicate Nanocomposites: Gas Permeation Properties and Clay Exfoliation

Self-Assembling of Tetradecylammonium Chain on Swelling High Charge Micas (Na-Mica-3 and Na-Mica-2): Effect of Alkylammonium Concentration and Mica Layer Charge

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