Clay intercalates

Nitrile Rubber. Vulcanized mbber sheets of NBR and montmorillonite clay intercalated with Hycar ATBN, a butadiene acrylonitrile copolymer have been synthesized (36). These mbber hybrids show enhanced reinforcement (up to four times as large) relative to both carbon black-reinforced and pure NBR. Additionally, these hybrids are more easily processed than carbon black-filled mbbers. 

Nylon-6. Nylon-6—clay nanometer composites using montmorillonite clay intercalated with 12-aminolauric acid have been produced (37,38). When mixed with S-caprolactam and polymerized at 100°C for 30 min, a nylon clay—hybrid (NCH) was produced. Transmission electron microscopy (tern) and x-ray diffraction of the NCH confirm both the intercalation and molecular level of mixing between the two phases. The benefits of such materials over ordinary nylon-6 or nonmolecularly mixed, clay-reinforced nylon-6 include increased heat distortion temperature, elastic modulus, tensile strength, and dynamic elastic modulus throughout the —150 to 250°C temperature range. 

Akelah andMoet [62] followed a modified approach to prepare PS-clay intercalated nanocomposites using a solvent to facilitate intercalation. MMT was ion exchanged using a polymerizable surfactant, vinylbenzyltrimethylammonium chloride. Acetonitrile was found to be the most effective solvent, producing a d-spacing of 2.45 mn versus 2.22 and... 

The incorporation of unmodified and organically modified montmorillonite nanoclays (namely 15A and 30B) in chlorinated polyethylene (CPE) by the solution intercalation method and their influence on mechanical properties of the nanocomposites have been studied by Kar et al. [137]. The o-MMT-embedded nanocomposites show enhanced tensile strength and Young s modulus in comparison to the nanocomposites containing the unmodified nanoclay. They have shown from and XRD analyses that organically modified clay shows better dispersion in the CPE matrix. This has been further substantiated from FTIR analysis, which proves an interaction between the CPE matrix and the clay intercalates. 

Layered silicate clays intercalated by pillaring poly-oxocations are precursors to an important class of mi-croporous catalysts. Smectite clay was the only host structure known to be pillarable by purely inorganic oxo ions. Recently, layered double hydroxides (LDH) pillaring oxo ions were reported by Pinnavaia and coworkers [79, 80]. 

Breen (1999) NMR Bentonite clays Intercalation of polymers + + n.a. Intercalation kinetics and ordering... 

A series of cluster complexes has been intercalated into hectorite, again with P-P+ as the cationic ligand. Typical is the formation of 1t4(CO)9(P-P+)3 within the clay. Intercalation of the clusters within the clay causes an increase in the interlayer spacing to as large as 17.5 A. 

F. Bedioui, Zeolite-encapsulated and Clay-intercalated Metal Porphyrin, Phthalocyanine and Schiff-base Complexes as Models for Biomimetic Oxidation Catalysts an Overview. Coord. Chem. Rev., 1995, 144, 39—68. 

Lan and Pinnavaia [6] showed that hybrid organic-inorganic composites exhibited mechanical properties superior to those for their separate composites. Dependence of tensile strength and modulus of epoxy nano-clay composites on the chain length of the clay-intercalated alkylammonium ions is shown in Fig. 28. The presence of the organoclay substantially increased both the tensile strength and modulus relative to the pristine polymer. The mechanical properties increased with any exfoliation in the order ... 

Novel clay intercalated metal catalysts a study of the hydrogenation of styrene and 1-octene on clay intercalated Pd catalysts... 

The research on the catalytic applications of clay minerals has been the subject of considerable interest for some time [1-2]. On account of their lamellar structure, clays can be excellent host materials for various metals, and thus the precursors of clay intercalated metal catalysts [3]. This paper reports on the catalytic behaviour of novel Pd intercalated montmorillonites. 

The catalytic application of montmorillonites may either be related to their acidity [5-7], or their swelling properties [8-9], Swelling, induced by careful selection of both the reaction medium and interlayer cations, enables the reactant molecules to enter the interlamellar region and undergo catalytic reaction on interstitial active sites. Moreover, the layered structure of montmorillonite may induce a substrate selectivity depending on the reactant size. Therefore, clay intercalated metal catalysts offer potential applications in the preparation of fine chemicals. 

Several review articles have dealt with various aspects of cycloaddition reactions. A short review has presented examples to illustrate the use to which tethered alkenes can be put in the synthesis of cyclobutenes. The photochemical (2 + 2)-cycloaddition of enones to ethene has been studied from a theoretical standpoint. A review has highlighted the use of linear templates to control photochemical reactions such as (2 + 2)-photocycloadditions. The stereochemical control of photochemical reactions in clay-intercalated compounds has been discussed. A review has highlighted the interdisciplinary nature of photochemistry. ... 

Frequent alternation of clay intercalations with thin oil-saturated beds of high SP resistivities ... 

The situation is quite different for the thermal expansion coefficient, a. Addition of clay slightly reduce its value in the solid state, but it affects it sttongly in the melt. Characteristically, melting of PA-6 initially decreases a, while that of PNC-5 increases it—the latter effect most likely is related to the thermal decomposition of clay intercalant. 

Hou. S.S. Beyer. F.L. Schmidt-Rohr, K. High-sensitivity multinuclear NMR spectroscopy of a smectite clay and of clay-intercalated polymer. Solid State Nucl. Magn. Reson. 2002. 22. 110-127. 

Takagi, K. Usami, H. Fukaya. H. Sawaki. Y. Spatially controlled photocycloaddition of a clay-intercalated stilba-zolium cation. J. Chem. Soc.. Chem. Commun. 1989. 1174-1175. 

From the work just discussed it is clear that clay intercalation of porphyrins can be done efficiently. The rapid development of materials such as larger-pore pillared clays should lead to more intense exploration of this area. 

H. Sh. Xia, M. Song, Characteristic length of dynamic glass transition based on polymer/clay intercalated nanocomposites. Thermo. Acta 2005, 429, 1. 

Kato, M., Usuki, A. and Okada, A. (1997). Synthesis of Polypropylene Oligomer - Clay Intercalation Compounds, /. Appl. Polym. Sci, 66(9) 1781-1785. 

Table -4 Interlamellar spacings (A) and stacking sequences of anionic clays intercalated with some oxo-anions or halides.

Bedioui, F. (1995). Zeohte-encapsulated and clay-intercalated metal porphyrin, phthalocyanine and Schiff-base complexes as models for biomimetic oxidation catalysts—an overview. Coord. Chem. Rev. 144, 39-68. 

Mainil, M., Alexandre, M., Monteverde, R, and Dubois, P. 2006. Polyethylene organo-clay nanocomposites The role of the interface chemistry on the extent of clay intercalation/exfoliation. Journal of Nanoscience and Nanotechnology 6 337-344. 

Scheme of the clay intercalation process with two PP- -MAH compatibilizers at low and high molecular weight as well as high and low MAH grafting degree. (Reprinted from Perrin-Sarazin, F. et al Polymer, 46,11624,2005. 

Chaudhary, D. S., Prasad, R., Gupta, R. K., and Bhattacharya, S. N. 2005. Clay intercalation and influence on crystallinity of EVA-based clay nanocomposites. Thermochimica Acta 433 187-195. 

Cole K. C. 2008. Use of infrared spectroscopy to characterize clay intercalation and exfoliation in polymer nanocomposites. Macromolecules 41 834-843. 

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