Anionic surfactants between double metal hydroxide layers

Kopka, H; Beneke, K.; Lagaly, G.

doi:10.1016/0021-9797(88)90263-9

Cited by 168 publications

(101 citation statements)

References 24 publications

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“…XRD patterns (a) and FTIR spectra (b) of LDH-NO 3 and LDH-CO 3 carbonate contamination, a weak peak at 2" = 11.5°( 0.77 nm), related to the co-intercalation of carbonate anions, still exists for all of the samples. A perpendicular orientation of surfactants in organoLDHs has been observed in previous studies [47][48][49]. Indeed, due to the small equivalent area of LDHs, the surfactants form generally mono-or bimolecular films instead of lying flat on the interlamellar surfaces.…”

Section: Muksing Et Al -Express Polymer Letters Vol5 No5 (2011) 4supporting

confidence: 61%

Effect of surfactant alkyl chain length on the dispersion, and thermal and dynamic mechanical properties of LDPE/organo-LDH composites

Muksing¹,

Magaraphan²,

Coiai³

et al. 2011

Express Polym. Lett.

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Abstract. Low density polyethylene/layered double hydroxide (LDH) composites were prepared via melt compounding using different kinds of organo-LDHs and polyethylene-grafted maleic anhydride as the compatibilizer. The organo-LDHs were successfully prepared by converting a commercial MgAl-carbonate LDH into a MgAl-nitrate LDH, which was later modified by anion exchange with linear and branched sodium alkyl sulfates having different alkyl chain lengths (n c = 6, 12 and 20). It was observed that, depending on the size of the surfactant alkyl chain, different degrees of polymer chain intercalation were achieved, which is a function of the interlayer distance of the organo-LDHs, of the packing level of the alkyl chains, and of the different interaction levels between the surfactant and the polymer chains. In particular, when the number of carbon atoms of the surfactant alkyl chain is larger than 12, the intercalation of polymer chains in the interlayer space and depression of the formation of large aggregates of organo-LDH platelets are favored. A remarkable improvement of the thermal-oxidative degradation was evidenced for all of the composites; whereas only a slight increase of the crystallization temperature and no significant changes of both melting temperature and degree of crystallinity were achieved. By thermodynamic mechanical analysis, it was evidenced that a softening of the matrix is may be due to the plasticizing effect of the surfactant.

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Section: Muksing Et Al -Express Polymer Letters Vol5 No5 (2011) 4supporting

confidence: 61%

Effect of surfactant alkyl chain length on the dispersion, and thermal and dynamic mechanical properties of LDPE/organo-LDH composites

Muksing¹,

Magaraphan²,

Coiai³

et al. 2011

Express Polym. Lett.

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“…Intercalation of organic molecules into HT is generally accompanied by an increase in d(001)-value (Kopka et al, 1988;Hermosin et al, 1996). Samples of HT and HT500 with large amounts of adsorbed herbicide are required.…”

Section: Resultsmentioning

confidence: 99%

“…This interlayer is 1.17 ,~ larger than the size of the molecule (4.3 A), based on scale models of the molecule. This difference is probably related to the electrostatic attraction of the PO3 2 and COO groups exerted by each of the positivelycharged brucite-like layers, which required a tilted arrangement of the molecule, as is common with other intercalated-organic anions in HT (Clearfield et al, 1991;Kopka et al, 1988).…”

Section: Discussionmentioning

confidence: 99%

Glyphosate-Hydrotalcite Interaction as Influenced by pH

Martín

Villa

Sánchez‐Camazano

1999

Clays and clay miner.

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Abstract--Adsorption and the mechanism of adsorption of the herbicide glyphosate [N-(phosphonomethyl) glycine] by hydrotalcite (HT) and by hydrotalcite calcined at 500~ (HT500) was studied. The values of the Freundlich K constant of the adsorption isotherms and the distribution coefficients, Kd, depend on the pH of the adsorption system and vary between 55.54-9603 (K) and 36.82-6252 (Kd) for HT and between 10,106-23,242 (K) and 17,801-26,558 (Kd) for HT500. X-ray diffraction and infrared spectroscopy studies showed that glyphosate is not adsorbed into the interlayer of HT. The adsorption mechanisms are (1) electrostatic attraction between the surface of HT, charged positively below pH 12 according to its point of zero charge and the glyphosate anion, and (2) ligand exchange between the P-OH and/or C=O groups of the herbicide and the A1 and Mg atoms of the HT surface. The occurrence of one or both mechanisms depends on the pH of the adsorption system. These adsorption mechanisms and the amphoteric nature of glyphosate account for the variation in K and Kd values with respect to pH. Previous studies on adsorption of different organic anions by HT have only considered the mechanism of anion exchange as important.

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“…This layer charge, in naturally occurring HT, is balanced by interlayered carbonate. As HTs are laminar and capable of anion-exchange reactions, they can be conceptualized as being the anionic equivalent of cationic clays (Miyata 1973(Miyata , 1975(Miyata , 1980(Miyata , 1983Kopka et al 1988;Cavani et al 1991;Mckenzie et al 1992). Sato et al (1986) have prepared magnesium aluminum oxide solid solutions by thermal decomposition of an HT-like compound.…”

Section: Introductionmentioning

confidence: 99%

¹³¹I⁻ Sorption by Thermally Treated Hydrotalcites

Olguín

Bosch

Acosta

et al. 1998

Clays and clay miner.

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Abstract--The sorption capacity of hydrotalcite (HT) and its calcined product (CHT) was evaluated for 131I-sorption from water solution and it was determined as a function of the calcining temperature. The radionuclide content was determined by 3,-spectrometry. Solids were characterized by thermal analysis, X-ray diffraction (XRD), electron microscopy and Brunauer-Emmett-Teller (BET) analysis. For 0.1 M Na I solution, labeled with t3~I , sorption capacity was found to be 0.24 meq g ~ (7.2% of the anion exchange capacity, AEC). But, if the sample was previously calcined at 773 K and the HT structure destroyed, the sorption of I-increased considerably, up to 2.08 meq g-~ (63% of the AEC) and the HT structure was reconstructed. The 1311-sorption at very low concentrations (10 -14 M) was 0.04 • 10 -14 meq of ~3~I g-~ in the noncalcined HT, but for calcined samples at 773 K, the sorption increased to circa 0.97 • 10 -~4 meq g 1. Calcination temperature determines the surface area of the resulting mixed oxides, and that property seems to be the most important factor controlling the I-sorption. If the calcination temperature was increased to 873 K, the specific surface area of the oxide mixture increased and I-sorption increased as well, whereas calcination of HT at 973-1073 K resulted in a low surface area and a low I retention.

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Anionic surfactants between double metal hydroxide layers

Cited by 168 publications

References 24 publications

Effect of surfactant alkyl chain length on the dispersion, and thermal and dynamic mechanical properties of LDPE/organo-LDH composites

Effect of surfactant alkyl chain length on the dispersion, and thermal and dynamic mechanical properties of LDPE/organo-LDH composites

Glyphosate-Hydrotalcite Interaction as Influenced by pH

¹³¹I⁻ Sorption by Thermally Treated Hydrotalcites

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Anionic surfactants between double metal hydroxide layers

Cited by 168 publications

References 24 publications

Effect of surfactant alkyl chain length on the dispersion, and thermal and dynamic mechanical properties of LDPE/organo-LDH composites

Effect of surfactant alkyl chain length on the dispersion, and thermal and dynamic mechanical properties of LDPE/organo-LDH composites

Glyphosate-Hydrotalcite Interaction as Influenced by pH

131I− Sorption by Thermally Treated Hydrotalcites

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Product

Resources

About

¹³¹I⁻ Sorption by Thermally Treated Hydrotalcites