Montmorillonite nanoparticles

The concentration of Cd(II) was determined using a carbon paste electrode modified with organofunctionalized amorphous silica with 2-benzothiazolethiol [402] or diacetyldioxime [403] and differential pulse anodic stripping voltammetry. The same method was used for determination of Cd(II) ion using GC electrode modified by antraquinone improved Na-montmorillonite nanoparticles [404]. 

Bacterial hydrogenase Montmorillonite nanoparticles Modified electrodes [52]... 

Montmorillonite nanoparticles can act as nucleating agents enhancing the crystallization rate of PET prepared by in situ polymerization in the presence of exfoliated mont-morillonite. Good dispersion of nanoparticles in exfoliate plays an importarrt role. ... 

Montmorillonites / poly(N-isopropyl acrylamide) [16] Norfloxacin Semi-interpenetrated network hydrogels Allows multiresposive drug delivery systems. Norfloxacin release controlled by the presence of montmorillonite nanoparticles and by the viscosity of swollen hybrid hydrogels. Formulations of the hybrid network with Dellite 67 G. nanoparticles showed a better sustained release than that of composites with Dellite HPS and a better balance between the relaxation time and the amount of released drug. 

In general, nanoclays have a large class of categories with different compositions which will alter the properties hence only two members, halloysite and montmorillonite nanoparticles, are thoroughly discussed to give an insight to nanoclays in general. 

The successful preparation of polystyrene-montmorillonite nanocomposites is very troublesome. More needs to be known about the structure-property relationships that exist with polystyrene in conjuction with the introduction of montmorillonite nanoparticles into the polymer before proper nanocomposites can be prepared. 

Feng S-S, Mei L, Anitha P, Gan CW, Zhou W. Poly(lactide)-vitamin E derivative/montmorillonite nanoparticle formulations for the oral delivery of Docetaxel. Biomaterials 2009 30(19) 3297-306. 

In recent times, polyhedral oligomeric silsesquioxane (POSS) has been used as organic modifier, for montmorillonite nanoparticles in nanocomposite preparation [120-123]. However, much of the literature is on monopolymer nanocomposites. 

Pozsgay, A., Frdter, X, Papp, L., Sajo, 1., Pukanszky, B. Nucleating effect of montmorillonite nanoparticles in polypropylene. J. Macromol. Sci. Part B Physics 41, 1249-1265 (2002)... 

In order to explore the interrelation of nanocomposite structure with materials performance, characterization with different techniques was carried out. Durometer hardness (Shore A) data, as a function of nanoparticle loadings, are presented in Table 17.5. Montmorillonite nanoparticles, and especially that of Cloisite 20A, are more efficient for... 

PP-g-MA) silicate nanocomposites and intercalated thermoset silicate nanocomposites for flame-retardant applications were characterised by XRD and TEM [333], XRD, TEM and FTIR were also used in the study of ID CdS nanoparticle-poly(vinyl acetate) nanorod composites prepared by hydrothermal polymerisation and simultaneous sulfidation [334], The CdS nanoparticles were well dispersed in the polymer nanorods. The intercalation of polyaniline (PANI)-DDBSA (dodecylbenzene-sulfonate) into the galleries of organo-montmorillonite (MMT) was confirmed by XRD, and significantly large 4-spacing expansions (13.3-29.6A) were observed for the nanocomposites [335],... 

Malucelli, F. Terribile, F. Colombo, C. (1999) Mineralogy, micromorphology and chemical analysis of andosols on the Island of Sao Miguel (Azores). Geoderma88 73-98 Mamedov, A. Ostrander, J. Aliev, F. Kotov, N.A. (2000) Stratified assemblies of magnetite nanoparticles and montmorillonite prepared by layer-by-layer assembly. Langmuir 16 3941-3949... 

In the case of LASIP with clay nanoparticles, polystyrene was grafted using a DPE coinitiator. The montmorillonite clay surface and intergallery interfaces were intercalated with 1,1-diphenylethylene (DPE) modified to be an organic cation as shown in Fig. 4. Its intercalation was confirmed by a series of characterization methods including X-ray diffraction (XRD), FT-IR spectroscopy, TGA, and XPS. The results showed a complete replacement of... 

Nanoparticles are now being investigated and used to provide some extra stiffness to polyurethanes. These are very small, flat, claylike platelets of micron size. Montmorillonites of size 2 to 13 microns have been used. They can have functional groups such as amine attached to them. The particles have to be fully defoliated and wetted by the polyurethane. The functional groups will bond to the hard segments. 

FIGURE 10.14 Compression force versus gap of EVA/PA6/APP-based intumescent formulations measured at400°C without (REF) and with nanoparticles (Si02, silica OMMT, organomodified montmorillonite LDH, lamellar double hydroxide). 

The FR properties of polymer-layered silicate nanocomposites have been studied for a wide range of polymers, especially for organomodified montmorillonites (OMMT) in thermoplastics. Depending on the nature of the polymer, the decomposition pathway and decomposition products may change.8 A major consequence of the introduction of modified clays is the formation or the enhancement of charred structure, caused by cross-linking processes possibly catalyzed by the nanoparticles. 

In the previous several years, various nanoparticles have been assembled into pairs to fabricate polymer nanocomposites, such as clay/silica (45), clay/carbon black (43), CNTs/clay (41,42), and CNTs/Titanium (38). Polymer/CNTs/clay ternary composite is one of most important multiphase systems with interesting synergistic effect, where sodium based montmorillonite (MMT) are the most commonly used layered clay. In this chapter, we will select some typical examples to demonstrate the importance and synergies of using CNTs and clay together in the preparation of polymer nanocomposites. 

The pillared and nanoparticle-containing montmorillonites open up new venues for the application of clay minerals in organic syntheses and production of composite materials. 

Another example of the formation of nanoparticles in the interlayer space is the solid-state reaction of manganese(II)-montmorillonite or and sodium sulfide. 

We could demonstrate that haemoglobin adsorbs to colloidal clay nanoparticles prepared from sodium montmorillonite and a Pt-poljrvinyl alcohol colloid onto glassy carbon electrodes [57] Hb displayed a quasi-reversible one-electron transfer process with an = - 370 mV (vs. Ag/AgCl), AEp = 130 mV and = 70 s . The linear dependence of the peak currents from the scan rate is indicative of a surface process (Fig. 2.4a). 

Examples of the use of nanostructured materials for packaging applications have been given in Chaudhry et al. (2008) and references therein. One of the first market entries into the food packaging arena was polymer composites containing clay nanoparticles (montmorillonite). The natural nanolayer structure of the clay particles impart improved barrier properties to the clay-polymer composite material. Some of the polymers which have been used in these composites for production of packaging bottles and films include polyamides, polyethylene vinyl acetate, epoxy resins, nylons, and polyethylene terephthalate. 

Cattech highlights (1997) Zeolites and chirality, Cattech, 1,149-151. Mastalir, A., Szollosi, G., Kiraly, Z., Razga, Z. (2002) Preparation and characterization of platinum nanoparticles immobilized in dihydrocin-chonidine-modified montmorillonite and hectorite, /i/i/. Clay Sci. 22,9-16. Gross, L.H., Rys, P. (1974) Heterogeneous catalytic asymmetric hydrogenation, J. Org. Chem. 39, 2429-2430. 

Bouanani F, Bendedouch D, Hemery P, et al. (2008) Encapsulation of montmorillonite in nanoparticles by miniemulsion polymerization. Colloid Surf A Physicochem Eng Asp... 

Mechanical Properties Toyota Central Research Laboratories in Japan was the first to obtain significant mechanical improvement of a PA matrix by adding as little as about 2 wt% of montmorillonite (MMT) [Kojima et ah, 1993 Usuki et ah, 1993 Okada and Usuki, 2006], Improvement in the mechanical properties on the vitreous and rubbery plateau by layered silicate nanoparticles depends on several factors, including clay surface modification, polymer chemistry, processing method, level of exfoliation, and clay orientation. In this section we present an overview of the influence of these factors on the dynamic mechanical properties of PLSN. 

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