@article { ISI:000206190100007, title = {Photo-oxidation of EPDM/layered double hydroxides composites: influence of layered hydroxides and stabilizers}, journal = {Express Polymer Letters}, volume = {1}, number = {11}, year = {2007}, month = {NOV}, pages = {748-754}, publisher = {BUDAPEST UNIV TECHNOL \& ECON}, type = {Article}, address = {DEPT POLYMER ENG, MUEGYETEM RKP 3, BUDAPEST, H-1111, HUNGARY}, abstract = {

The photo-oxidation of ethylene propylene diene monomer (EPDM)/layered double hydroxide (LDH) composites as well as EPDM/LDH with stabilizers is studied under accelerated UV irradiation (lambda \>= 290 nm) at 60 degrees C for different time intervals. The development of functional groups during oxidation was monitored by FT-IR spectroscopy. The photo-degradation of the pristine polymer and composites take place and the increase in hydroxyl and carbonyl groups with irradiation times, was estimated. EPDM filled LDH showed higher degradation rate than pristine EPDM, while in acidic medium EPDM/LDH showed almost equal degradation as in isolated conditions. These results show the advantages of LDHs as a filler as well as an acid killer. The effect of stabilizers is very less because of their concentration in comparison of LDH.

}, keywords = {EPDM, layered double hydroxides, Photo-oxidation, polymer composites}, issn = {1788-618X}, doi = {10.3144/expresspolymlett.2007.103}, author = {Kumar, B. and Rana, S. and Singh, R. P.} } @article { ISI:000267546200006, title = {Structural characterization of azoic dye hosted layered double hydroxides}, journal = {Zeitschrift fur Kristallographie}, volume = {224}, number = {5-6}, year = {2009}, month = {JAN}, pages = {282-286}, publisher = {OLDENBOURG VERLAG}, address = {LEKTORAT MINT, POSTFACH 80 13 60, D-81613 MUNICH, GERMANY}, abstract = {

The removal of methyl orange (MO) from an aqueous solution was performed using layered double hydroxides (LDHs) in a move to develop cleaning processes of effluents contaminated with dye molecules. The intercalation of the guest anionic MO species into host M(II)/Al(III) LDHs differing by the nature of the divalent cations (M(II) = Mg, Ni or Zn) was achieved by anionic exchange of the initially NO(3)(-) present in the interlayer space and led to MO/LDH intercalation compounds. The exchange process was followed by XRD and UV-visible absorption spectroscopy at different stages. Almost all MO in solution is uptaken by the Mg-containing LDH in the concentration range corresponding to its anionic exchange capacity (AEC). A lower exchange is reached with the Ni- and Zn-containing LDHs, for which the diffusion of MO is limited due to a larger crystallite size. MO-Zn/Al LDH intercalation compounds exhibit the highest crystallinity and display a remarkable stacking of the layers at maximal MO exchange. This behaviour can be assigned to the higher intrinsic charge density of the host layers in agreement with its lower M(II)/Al(III) molar ratio (Zn(II)/Al(III) approximate to 1.5 whereas Mg(II)/Al(III) and Ni(II)/Al(III) = 2). The maximum amount of MO retained by the different LDHs is higher for Mg-containing LDH, than for Ni- and Zn-containing LDH, reaching respectively 1.15, 0.84 and 0.77 g/g.

}, keywords = {Anionic exchange, Depollution, layered double hydroxides, Methyl orange, X-ray diffraction}, issn = {0044-2968}, doi = {10.1524/zkri.2009.1150}, author = {Mandal, Sujata and Lerner, Dan A. and Marcotte, Nathalie and Tichit, Didier} } @article { ISI:000274069000060, title = {Preparation and characterization of novel hybrid of bio-assisted mineralized Zn-Al layered double hydroxides using chitosan as a template}, journal = {Journal of Applied Polymer Science}, volume = {115}, number = {6}, year = {2010}, month = {MAR}, pages = {3636-3644}, publisher = {JOHN WILEY \& SONS INC}, address = {111 RIVER ST, HOBOKEN, NJ 07030 USA}, abstract = {

The purpose of this study was to prepare and characterize a novel nanohybrid prepared from the template-assisted mineralization of Zn-Al Layered Double Hydroxide (LDH) onto the surface of Chitosan (CSI), with an emphasis on morphology, biocompatibitity, and its use as an efficient drug carrier agent. The as prepared LDH is highly crystalline, with platelet-like morphology and curved tactoids when nucleated onto the surface of CSI. Our results indicate that the -OH and -NH functional moieties on CSI can direct an ordered structure of LDH, due to the electrostatic interaction between biopolymer and inorganic lamellae. We have been successful to intercalate an anti-inflammatory drug, Sodium Ibuprofen (Ibu), into LDH, through conventional coprecipitation method. LDHs are endowed with great potential for delivery vector because their stacked layers lead to safe reservation of biofunctional molecules or genes, and their ion exchangeability and solubility in acidic media (pH \< 4) give rise to the controlled release of drug molecules. According to the cell-growth studies, LDHs are found as cell viable up to the concentration of 500 mu g/mL. This study reveals that LDH not only plays a role of a biocompatible-delivery matrix but also facilitates a significant increase in the delivery efficiency. (C) 2009 Wiley Periodicals, Inc. J Appl Polym Sci 115:3636-3644,2010

}, keywords = {bio-assisted mineralization, cell-growth studies, Chitosan, drug delivery systems, layered double hydroxides}, issn = {0021-8995}, doi = {10.1002/app.31463}, author = {Depan, Dilip and Singh, Raj Pal} } @article { ISI:000297940300004, title = {Influence of reactive compatibilization on the structure and properties of PP/LDH nanocomposites}, journal = {Polymer International}, volume = {60}, number = {12}, year = {2011}, month = {DEC}, pages = {1688-1696}, publisher = {WILEY-BLACKWELL}, address = {COMMERCE PLACE, 350 MAIN ST, MALDEN 02148, MA USA}, abstract = {

Polypropylene (PP)/layered double hydroxide (LDH) nanocomposites were prepared by the direct melt intercalation method usingmaleic anhydride grafted polypropylene (PP-g-MAH) as a reactive compatibilizer. The compatibilization effects provided by PP-g-MAH in different weight fractions and their influence on the structure and properties of the final nanocomposites were investigated. The interactions and structural morphology of the nanocomposites were examined by Fourier transform infrared spectroscopy, X-ray diffraction and transmission electronmicroscopy. Thermal, mechanical and rheological properties of these nanocomposites were investigated as a function of compatibilizer concentration. The detailed morphological and X-ray diffraction results revealed that the degree of LDH dispersion increases as the amount of PP-g-MAH increases. Study of the linear viscoelastic properties showed that the storage modulus G{\textquoteright} is very sensitive to the microstructure of the nanocomposite. The thermal properties of the nanocomposites were significantly influenced by the weight fraction of PP-g-MAH due to the shielding and nucleating effect of exfoliated layers. Both the tensile strength and modulus showed substantial improvements with increasing PP-g-MAH content, while the elongation at break substantially decreased, although the presence of PP-gMAH somewhat improves these values. The overall results showed that 10 wt\% of compatibilizer is optimum to achieve nanocomposites with better performance. (C) 2011 Society of Chemical Industry

}, keywords = {compatibilization, layered double hydroxides, Nanocomposites, polypropylene, Rheology, thermomechanical properties}, issn = {0959-8103}, doi = {10.1002/pi.3129}, author = {Lonkar, Sunil P. and Therias, Sandrine and Leroux, Fabrice and Gardette, Jean Luc and Singh, Raj Pal} } @article {46853, title = {Co@CoAl-layered double hydroxide/nitrogen-doped graphene composite catalyst for Al-H2O-based batteries: simultaneous hydrogen production and electricity generation}, journal = {ChemElectroChem}, volume = {7}, year = {2020}, month = {JUN}, pages = {2582-2591}, type = {Article}, abstract = {

Currently, the low energy efficiency of water electrolysis has compelled research toward the development of novel and energy-effective strategies for low-cost H-2 generation. In this context, we report a new concept of simultaneous H-2 and electricity generation by separating out the exothermic self-sustained Al-H2O reaction via electrochemistry. In addition, to catalyze the cathodic water reduction reaction, a single-pot and environmentally benign synthesis method is adopted. It results in the design of an electrocatalyst composed of Co@CoAl-layered double hydroxide core-shell nanospheres anchored over in situ generated N-doped graphene. Toward the water reduction reaction, the designed catalyst shows a negative voltage shift of mere around 113 mV with respect to the commercial Pt/C catalyst to reach the benchmark 10 mA cm(-2), with excellent stability of approximately 86 \% voltage retention after 12 h of continuous operation. The catalytic superiority of our material is evident when taken for battery-level testing; the fabricated device was able to deliver an average output voltage of around 0.95 V at a discharge current density of 5 mA cm(-2) along with H-2 liberation, which was also detected and quantified through gas chromatography.

}, keywords = {Al-H2O fuel cells, chronopotentiometry, core-shell structures, hydrogen evolution reaction, layered double hydroxides}, issn = {2196-0216}, doi = {10.1002/celc.202000502, Early Access Date = MAY 2020}, author = {Nadeema, Ayasha and Pandurang Kharabe, Geeta and Prakash Biswal, Dibya and Kurungot, Sreekumar} } @article {49073, title = {Investigation of structural and morphological insights of nanostructured layered double hydroxides: catalytic activity in aldol condensation}, journal = {Journal of Porous Materials }, volume = {31}, year = {2024}, month = {APR}, pages = {759-778}, type = {Article}, abstract = {

Layered double hydroxides (LDHs) materials finds extensive applications in numerous fields such as medical science, industrial sector, agriculture and food, catalysis, polymers, nanotechnology, etc. The LDHs properties (structural, textural, morphological, spectroscopic and theoretical insights) can be design for achieving required materials for particular application in scientific areas. In the current investigation, we have synthesized mesoporous nanostructured LDHs materials via microwave, sonication and stirring method. The nanostructured LDHs was scientifically characterized by various physico-chemical techniques like XRD, N2 sorption, TGA, solid state one-dimensional 27Al magic angle spinning NMR spectroscopy, XPS, Raman Spectroscopy, FT-IR, ICP-OES, Electron Microscopy (SEM, FE-SEM, TEM and HR-TEM), EDX, elemental analysis, etc. On the basis of experimental study, it can be evidently witnessed that nanostructured LDHs materials was formed with good crystalline mesoporous nature. Solid state 27Al NMR showed single and sharp 27Al NMR signal at chemical shift value of + 1.4 ppm, strongly suggesting the presence of octahedral (Oh) AlO6 coordination site in all as-synthesized LDHs. Microwave and sonication techniques furnishes regularly dispersed well-developed flower-shaped nanocrystals however, stirring method gives mostly agglomerated nano-sized platelets. The mechanistic insights for the fabrication of nanostructures LDHs via microwave, sonication and stirring process were also highlighted. The different LDHs materials were utilized in the aldol condensation reaction of furfural with acetone for understanding structure-activity correlation. Microwave and sonication methodologies can be further exploited for the synthesis of many other inorganic-organic nanocomposites materials with stable and good dispersion of nanocrystals in addition to desired morphology and catalytic activity.

}, keywords = {Aldol condensation, catalysis, Flower-shaped nanocrystals, layered double hydroxides, Microwave and sonication techniques, Nanostructured materials}, issn = {1380-2224}, doi = {10.1007/s10934-023-01545-w}, author = {Bhagat, Shailesh K. and Nagpure, Atul S. and Lanjewar, Mamata R. and Gode, Nilesh G. and Thakare, Sanjay R.} }