Layered double hydroxides compositions

He, R-A. and Zhang, L.-M. 2007. New polyethylene nanocomposites prepared by in-situ polymerization method using nickel a-diimine catalyst supported on organo-modified ZnAl layered double hydroxide. Composites Science and Technology 67 3226-3232. 

Bercea Maria, Bibire Elena-Livia, Morariu Simona, Teodorescu Mirela, and Carja Gabriela. pH influence on rheological and structural properties of chitosan/poly(vinyl alcohol)/ layered double hydroxide composites. Eur. Polym. J. 70 (2015c) 147-156. 

B. Ramaraj and K.-R. Yoon, Thermal and physicomechanical properties of ethylene-vinyl acetate copolymer and layered double hydroxide composites. Journal of Applied Polymer Science, 108 (2008), 4090-95. 

Zeng, L., Zhao, T.S., Li, Y.S., Synthesis and characterization of crosshnked poly (vinyl alcohol)/layered double hydroxide composite polymer membranes for alkaline direct ethanol fuel cells, Int. J. Hydrogen Energy, 2012, 37, 18425-18432. 

Layered materials are of special interest for bio-immobilization due to the accessibility of large internal and external surface areas, potential to confine biomolecules within regularly organized interlayer spaces, and processing of colloidal dispersions for the fabrication of protein-clay films for electrochemical catalysis [83-90], These studies indicate that layered materials can serve as efficient support matrices to maintain the native structure and function of the immobilized biomolecules. Current trends in the synthesis of functional biopolymer nano composites based on layered materials (specifically layered double hydroxides) have been discussed in excellent reviews by Ruiz-Hitzky [5] and Duan [6] herein we focus specifically on the fabrication of bio-inorganic lamellar nanocomposites based on the exfoliation and ordered restacking of aminopropyl-functionalized magnesium phyllosilicate (AMP) in the presence of various biomolecules [91]. 

Manzi-Nshuti, C., Wang, D., Hossenlopp, J. M., and Wilkie, C. A. Aluminum-containing layered double hydroxides The thermal, mechanical, and fire properties of (nano)composites of poly(methyl methacrylate), J. Mater. Chem. (2008), 18, 3091-3102. 

Fudala, A., Palinko, I. and Kiricsi, I. (1999). Preparation and characterization of hybrid organic-inorganic composite materials using the amphoteric property of amino acids amino acid intercalated layered double hydroxide and montmorillonite. Inorg. Chem. 38, 4653. 

Layered double hydroxides, also known as anionic clays, belong to a class of lamellar hydroxides with a structure related to that of brucite. A large number of these hydroxides are naturally available and many more have been synthesized in laboratories. The structure of brucite, Mg(OH)2, consists of sheets of edge-connected Mg(OH)6 octahedra, which are held together by means of Van der Waals forces. The sheets have the composition Mg(OH)2, and are electrically neutral. 

Unlike the smectites, the layered double hydroxides (LDH) are anionic clays in which brucite-like sheets are intercalated with anions instead of the cations found as charge balancing species in the smectites. The chemical compositions of the layered double hydroxides are provided in Table 5 . 

Liu, Z.P., Ma, R.Z., Osada, M., lyi, N., Ebina, Y., Takada, K., and Sasaki, T. 2006. Synthesis, anion exchange, and delamination of Co-Al layered double hydroxide Assembly of the exfoliated nanosheet/polyanion composite films and magneto-optical studies. Journal of the American Chemical Society 128. 4872-4880. 

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. 

The hydroxycarbonate precursors showed dif action patterns consistent with the layered double hydroxide structure proposed for hydrotalcite-like compounds, i.e., brucite-like sheets formed by OH groups and cations (Mg and AP ) in octahedral coordination. Water molecules and charge-compensating COs anions are located in the interlayers. The hydrotalcite-like precursor composition is [Mg,, .Al,(0H)2] (C03), . mH20 with r = Al/(A1+Mg) the stoichiometric hydrotalcite compound, Mg6Al2(0H)i6C03.4H20, is obtained for r = 0.25. Upon thermal decomposition at 673 K, the hydroxycarbonate precursors lose... 

Catalyst synthesis perhaps represents the most promising application of layered double hydroxides [24,46]. The thermal decomposition of LDH carbonates, for example, afford mixed metal oxides that often cannot be prepared by other methods. Several catalytic compositions for organic synthesis [47], methanol synthesis [48] and Fischer-Tropsdi synthesis, for example, [49]... 

Layered double hydroxides (LDHs) are complementary to smectite clays insofar as the charge on the layers and the gallery ions is reversed that is, the host layers of an LDH are 2D polyhydroxy cations and the gallery species hydrated anions. The compositions of LDHs are represented by the general formula [M j.jM j(OH)2][A"]jjy, z H2O, where A" is the gallery anion, and... 

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