Layered double hydroxides carbonate

In order to produce high-performance elastomeric materials, the incorporations of different types of nanoparticles such as layered silicates, layered double hydroxides, carbon nanotubes, and nanosilica into the elastomer matrix are now growing areas of rubber research. However, the reflection of the nano effect on the properties and performance can be realized only through a uniform and homogeneous good dispersion of filler particles in the rubber matrix. 

Layered double hydroxide carbonates of magnesium and aluminum are called hydrotalcites (e.g., Mg6Al2(OH)i6 CO3-H2O). They can be used as solid bases before or after calcination to produce mixed magnesium-aluminum oxides.74 They have been used to catalyze the addition of alcohols to acrylonitrile 75 the reduction of ketones with iso-... 

Zhao, J. W., J. Chen, S. M. Xn et al. 2014. Hierarchical NiMn layered double hydroxide/ carbon nanotubes architecture with superb energy density for flexible supercapacitors. Advanced Functional Materials 24 2938—2946. 

The dispersion and solid-state ion exchange of ZnCl2 on to the surface of NaY zeolite by use of microwave irradiation [17] and modification of the surface of active carbon as catalyst support by means of microwave induced treatment have also been reported [18]. The ion-exchange reactions of both cationic (montmorillonites) and anionic clays (layered double hydroxides) were greatly accelerated under conditions of microwave heating compared with other techniques currently available [19.]... 

Hydrotalcites are layered double hydroxides with the general formula Mg6Al2(0H)i6[C03].4H20. Loading these compounds with potassium carbonate strongly increases their C02 uptake [25, 35], Notably, the hydrotalcite structure already breaks down below 400 °C [26] into a mixed metal oxide. 

Fig.1 Idealized structure of a layered double hydroxide with interlayer carbonate anions. Several parameters are defined. Reprinted with permission from [6]. Copyright Elsevier...

Layered double hydroxides are materials of current interest iron-containing versions include Fe +/Ni + and Fe +/Mg " " with carbonate as intercalated counterion and Fe " /Ni + with sulfate. It is also possible to intercalate [Fe(CN)6]" (see Section 5.4.2.1.1), though apparently tris-oxalatoferrate(III) is reluctant to intercalate, at least into Al +/Mg + layered double hydroxide. ... 

Constantino V. R. L. and Pinnavaia, T. J. Basic properties of Mgj x2+Alx3+ layered double hydroxides intercalated by carbonate, hydroxide, chloride, and sulfate anions, Inorg. Chem., 1995, 34, 883-92. 

Provided in this chapter is an overview on the fundamentals of polymer nanocomposites, including structure, properties, and surface treatment of the nanoadditives, design of the modifiers, modification of the nanoadditives and structure of modified nanoadditives, synthesis and struc-ture/morphology of the polymer nanocomposites, and the effect of nanoadditives on thermal and fire performance of the matrix polymers and mechanism. Trends for the study of polymer nanocomposites are also provided. This covers all kinds of inorganic nanoadditives, but the primary focus is on clays (particularly on the silicate clays and the layered double hydroxides) and carbon nanotubes. The reader who needs to have more detailed information and/or a better picture about nanoadditives and their influence on the matrix polymers, particularly on the thermal and fire performance, may peruse some key reviews, books, and papers in this area, which are listed at the end of the chapter. 

The 0-d nanoparticles can be nano-metal oxides (such as silica,1 titania,2 alumina3), nano-metal carbide,4 and polyhedral oligomeric silsesquioxanes (POSS),5 to name just a few the 1-d nanofibers can be carbon nanofiber,6 and carbon nanotubes (CNT),7 which could be single-wall CNTs (SWCNT) or multiwall CNTs (MWCNT) etc. the 2-d nano-layers include, but are not limited to, layered silicates,8 layered double hydroxides (LDH),9 layered zirconium phosphate,10 and layered titanates,11 etc. 3-d nano-networks are rarely used and thus examples are not provided here. 

Crepaldi, E. L., Pava, P. C., Valim, J. B. and Jones, W. (2000). Synthesis and thermal behaviour of copper-chromium-carbonate layered double hydroxides, in preparation. 

Complex precipitates, such as layered double hydroxides, are frequently prepared as precursors of oxide catalysts. Hydrotalcite is a hydrated hydroxy-carbonate mineral with the formula Mg,sAl2(0H)i6C03-4H20. It represents the better known and most popular member of a family of layered double metal hydroxide com-... 

The decarbonation of carbonated layered double hydroxides containing Mg with either Al, Fe or Cr bivalent cations or A1 with Mg, Ni, Cu or Zn divalent cations has been studied by thermal analysis. The enthalpy of adsorption of CO2 on the resulting calcined mixed oxides was measured by calorimetry, with initial heats of adsorption close to those reported for MgO (about lOOkJmol ) and a relatively homogeneous strength distribution [100],... 

Names of precursors, intermediates and carbons are denoted by a mixture of the starting material, the procedure this starting material has undergone and important experimental conditions. For example, LSS1C673DC means Layered double hydroxide of StyreneSulfonate batch 1, Carbonised at 670 °C for 3 hours, subsequently Demineralised in HCF. 

Layered double hydroxides (LDHs) are a unique type of clay with anion exchange capacity. In nature, they are found in the carbonated hydrotalcite-like compounds... 

Layered double hydroxides are typically synthesized from coprecipitation of mixed metal cations by base titration either with or withont hydrothermal treatment which nsnally enhances crystalline properties." " Becanse contamination with airborne carbonate ions freqnently occurs during synthesis procedures, special caution is needed to prepare carbonate-free LDHs. On the other hand. 

Besides hydrogen, other reductants for O2 in the liquid-phase epoxidation of propene include carbon monoxide, aldehydes, alcohols and other organic compounds. The reaction proceeds very efficiently with methanol as the reductant, in the presence of Pd and the Ti-Al-MCM-22 catalyst or Pd and peroxo-polyoxometalate catalysts the latter have been intercalated inside layered double hydroxides to make them heterogeneous [29e,h]. A propene conversion of 47%, with 91.5% selectivity for PO, was obtained at 80°C [29h]. 

The relationship between electrochemical items and materials science can be grouped according to three main aspects as shown in Figure 1.1. It should be noted that electrosynthetic methods allow for preparing a variety of materials, from porous oxide layers in metal anodes, to MOFs (Mueller et al., 2006), layered double hydroxides (LDHs Yarger et al., 2008), and porous carbons (Kavan et al., 2004). Furthermore, porous materials can be modified, functionalized, or hybridized (yide infra) via electrochemically assisted procedures, thus resulting in the preparation of novel materials. 

Leroux. E, Raymundo-Pinero, E., Fedelec. J.-M.. and Beguin, F. 2006. Textural and electrochemical properties of carbon replica obtained from styryl organo-modified layered double hydroxide. Journal of Materials Chemistry 16, 2074-2081. 

Shaw, B.R., and Creasy, K.E. 1988. Carbon composite electrodes containing alumina, layered double hydroxides, and zeolites. Journal of Electroanalytical Chemistry 243, 209-217. 

Su, L.-H.. Zhang, X.-G., and Liu, Y. 2008. Electrochemical performance of Co-Al layered double hydroxide nanosheets mixed with multiwall carbon nanotubes. Journal of Solid State Electrochemistry 12, 1129-1134. 

Caija, G., Nakamura, R.. Aida. T. and Niiyama, H. (2003). Mg-V-AI mixed oxides with mesoporous properties using layered double hydroxides as precursors catalytic behavior for the process of ethylbenzene dehydrogenation to styrene under a carbon dioxide flow. 7. Coto/., 218, 104-110. 

Graphene-polymer nanocomposites share with other nanocomposites the characteristic of remarkable improvements in properties and percolation thresholds at very low filler contents. Although the majority of research has focused on polymer nanocomposites based on layered materials of natural origin, such as an MMT type of layered silicate compounds or synthetic clay (layered double hydroxide), the electrical and thermal conductivity of clay minerals are quite poor [177]. To overcome these shortcomings, carbon-based nanofillers, such as CB, carbon nanotubes, carbon nanofibers, and graphite have been introduced to the preparation of polymer nanocomposites. Among these, carbon nanotubes have proven to be very effective as conductive fillers. An important drawback of them as nanofillers is their high production costs, which... 

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