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Bentonite Clay (bentonite + clay)

Distribution by Scientific Domains
Polymers and Materials Science42%
Chemistry28%

Selected Abstracts

Transformations of Epoxide Derived from Nopol over Askanite,Bentonite Clay.

CHEMINFORM, Issue 19 2005
I. V. Il'ina
Abstract For Abstract see ChemInform Abstract in Full Text. [source]

Reactions of Allyl Alcohols of the Pinane Series and of Their Epoxides in the Presence of Montmorillonite Clay

HELVETICA CHIMICA ACTA, Issue 2 2007
Irina
Abstract The reactivity of allyl alcohols of the pinane series and of their epoxides in the presence of montmorillonite clay in intra- and intermolecular reactions was studied. Mutual transformations of (+)- trans -pinocarveol ((+)- 2) and (,)-myrtenol ((,)- 3a) were major reactions of these compounds on askanite,bentonite clay (Schemes,1 and 2). However, the two reactions gave different isomerization products, indicating that the reactivity of the starting alcohol (+)- 2 or (,)- 3a was different from that of the same compound (+)- 2 or (,)- 3 formed in the course of the reactions. (,)- cis - and (+)- trans -Verbenol ((,)- 16 and (+)- 12, resp.), as well as (,)- cis -verbenol epoxide ((,)- 20) reacted with both aliphatic and aromatic aldehydes on askanite,bentonite clay giving various heterocyclic compounds (Schemes,4, 5 and 7); the reaction path depended on the structure of both the terpenoid and the aldehyde. [source]

Molecular dynamics and multiscale homogenization analysis of seepage/diffusion problem in bentonite clay

INTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN ENGINEERING, Issue 12 2002
Y. Ichikawa
Abstract A scheme combining a molecular behaviour and macro-continuum phenomenon is presented for bentonite clay, which is a key component of a barrier system for disposal and containment of hazardous wastes. On designing a disposal facility we use a macro-phenomenological model. However the existing model is not sufficiently effective. Bentonite is a microinhomogeneous material. Properties of the saturated bentonite are characterized by montmorillonite and water, called montmorillonite hydrate. Since the crystalline structure of montmorillonite determines the fundamental properties of the montmorillonite hydrate, we analyse its molecular behaviour by applying a molecular dynamics simulation to enquire into the physicochemical properties of the montmorillonite hydrate such as diffusivity of chemical species. For extending the microscopic characteristics of constituent materials to a macroscopic diffusion behaviour of the microinhomogeneous material we apply a multiscale homogenization analysis, especially in order to treat micro-level of adsorption behaviour. Copyright © 2002 John Wiley & Sons, Ltd. [source]

Effect of clay/water ratio during bentonite clay organophilization on the characteristics of the organobentonites and its polypropylene nanocomposites

POLYMER ENGINEERING & SCIENCE, Issue 9 2009
Suédina M.L. Silva
A sodium bentonite (montmorillonite-based layered silicate clay) was organically modified with cetyl trimethyl ammonium bromide (cetrimide), using different clay/water ratios,but the same clay/cetrimide ratio,to suspend the bentonite clay and perform its organophilization. Infrared spectroscopy and thermogravimetric analysis indicated the incorporation of organic modifier into the bentonite. Wide-angle X-ray scattering showed that the incorporation of surfactant significantly increased the interlayer spacing in the bentonite for all concentrations studied. It was found that clay/water ratio employed during the modification affects neither the amount of organic salt incorporated nor the interlayer spacing in the organobentonites, but influences its degree of structural disorder. Lower clay/water ratios resulted in a more disorderly structure, as established by the decrease of the areas under the X-ray peaks as the clay/water ratio diminishes. The modified bentonites were melt compounded with maleic anhydride-grafted polypropylene. X-ray diffraction patterns of the hybrids revealed that the more disorderly organobentonites were better dispersed in the polymer matrix, indicating that, in the present system, the structure of polymer nanocomposites obtained were affected by the clay/water ratio used in organobentonite preparation. POLYM. ENG. SCI., 2009. © 2009 Society of Plastics Engineers [source]

Synthesis and characterization of styrene butadiene rubber,Bentonite clay nanocomposites

POLYMER ENGINEERING & SCIENCE, Issue 7 2009
Sugata Chakraborty
In the present study, naturally occurring unfractionated bentonite clay was used to prepare styrene butadiene rubber/bentonite clay nanocomposite by latex stage blending. The bentonite clay was organo-modified by in situ resol formation by the reaction of resorcinol and formaldehyde. The latex clay mixture was co-coagulated with acid. The resulting clay masterbatch was compounded and evaluated by Fourier Transform Infrared spectroscopy, X-ray diffraction (XRD), Transmission Electron Microscopy (TEM), Energy Dispersive X-ray spectroscopy (EDS), Scanning Electron Microscopy, Thermogravimetric analysis, and Differential Scanning Calorimetry. XRD showed that the interplanar distance of the in situ resol-modified bentonite clay increased from 1.23 to 1.41 nm for the unmodified bentonite. TEM analysis indicated partial exfoliation and/or intercalation. EDS (Si and Al mapping) of the clay revealed the nature of the dispersion in the nanocomposites vis-à-vis the conventional styrene-butadiene rubber (SBR)/bentonite clay composite. Thermogravimetric analysis was used to compare the decomposition trends of the SBR/clay nanocomposites with the SBR/clay composite. The glass transition temperature of SBR/clay nanocomposites increased as compared with that of neat SBR. Substantial improvement in most of the other mechanical properties was also observed in case of the nanocomposites. POLYM. ENG. SCI., 2009. © 2009 Society of Plastics Engineers [source]

PVC nanocomposites,Nanoclay chemistry and performance,

JOURNAL OF VINYL & ADDITIVE TECHNOLOGY, Issue 4 2008
Daphne Benderly
Nanoclay applications in poly(vinyl chloride) (PVC) have been limited, as the organic modifier of conventional nanoclays can promote PVC degradation. Novel nanoclays designed for enhanced PVC compatibility were compounded with PVC. Hectorite and bentonite clays were studied as nanoclay fillers. Two incorporation methods were evaluated to determine the effect on nanoclay dispersion and composite performance. A two-stage method, in which the nanoclay was predispersed in plasticizer, resulted in good nanoclay dispersion at both the micrometer and nanometer scales. The nanocomposites were characterized by using a wide range of analytical tools. They exhibited significantly improved heat stability, an increase of up to 200% in storage modulus, and a decrease of up to 77% in oxygen permeation, as compared to unfilled PVC. Bentonite nanoclays provided a greater increase in barrier and mechanical properties. No change was seen in the PVC glass transition temperature. J. VINYL ADDIT. TECHNOL., 2008. © 2008 Society of Plastics Engineers [source]