Materials Literature
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Abstract Nylon‐66 nanocomposites were prepared by melt‐compounding nylon‐66 with an alkyl ammonium surfactant pretreated montmorillonite (MMT). The thermal stability of the organic MMT powders was measured by thermogravimetric analysis. The decomposition of the surfactant on the MMT occurred from 200 to 500 °C. The lo…
The structural, electronic, and adhesive properties of Cu/SiO$_2$ interfaces are investigated using first-principles density-functional theory within the local density approximation. Interfaces between fcc Cu and $α$-cristobalite(001) surfaces with different surface stoichiometries are considered. Interfacial properti…
Intramolecular spin alignment in pi-conjugated molecules is studied theoretically in a model of a Peierls-Hubbard chain coupled with two localized spins. By means of the exact diagonalization technique, we demonstrate that a spin singlet (S=0) to quartet (S=3/2) transition can be induced by electronic doping, dependin…
We investigate through molecular dynamics the transition from Knudsen to molecular diffusion transport towards 2d absorbing interfaces with irregular geometry. Our results indicate that the length of the active zone decreases continuously with density from the Knudsen to the molecular diffusion regime. In the limit wh…
The structure of the electron quantum size levels in spherical nanocrystals is studied in the framework of an eight-band effective-mass model at zero and weak magnetic fields. The effect of the nanocrystal surface is modeled through the boundary condition imposed on the envelope wave function at the surface. We show t…
Abstract Various polyblends of poly(vinyl chloride) and polyurethane (PU) dissolved in a mixture of tetrahydrofuran and N , N ‐dimethylformamide were produced by electrospinning, in different ratios, with several electrospinning conditions, and the relationship between morphology and mechanical behavior of the resulti…
Abstract The effect of the incorporation of a bentonite on the vulcanization kinetics of natural rubber was investigated by means of both cure‐meter testing and differential scanning calorimetry (DSC) under dynamic and isothermal conditions. The vulcanization curves showed that the modified clay behaved as an effectiv…
Using results from colloid science we derive interaction potentials for computer simulations of mixtures of soft or hard ellipsoids of arbitrary shape and size. Our results are in many respects reminicent of potentials of the Gay-Berne type but have a well-defined microscopic interpretation and no adjustable parameter…
Isolated europium-doped metal-oxide nanoparticles were probed by size-correlated high-numerical-aperture (far-field) imaging techniques. A modified Digital Instruments Bioscope atomic force microscope mounted upon a Nikon TE300 inverted microscope was used to interrogate (dry) particles ranging in size from 2 to 150 n…
Encapsulation of L-ascorbic acid (vitamin C) within a bio-compatible layered inorganic material was achieved by coprecipitation reaction, in which the layered inorganic lattice and its intercalate of vitamin C are simultaneously formed. The nano-meter sized powders of vitamin C intercalate thus prepared was again enca…
The supramolecular assembling of small, equimolar amounts of octyl-substituted complementary tectons based upon barbituric acid (BA) and 2,4,6-triaminopyrimidine (TP) in an isotactic and, particularly, in an atactic polypropylene matrix was studied by means of dynamic-mechanical spectroscopy. Self-organization of thes…
l-Colitose (1) is a 3,6-dideoxyhexose found in the O-antigen of gram-negative lipopoly-saccharides. While the biosynthesis of many deoxysugars have previously been investigated, l-colitose is distinct in that it originates from GDP-d-mannose. In contrast, other 3,6-dideoxyhexoses arise from CDP-d-glucose. Therefore, t…
As part of a program to investigate the linear and nonlinear susceptibilities of acetonitrile in the condensed phase, we report on the accurate calculation of the molecular electric properties of acetonitrile, taking into account geometry and basis set effects, static and dynamic electronic correlation, vibrational co…
Diels-Alder reactions of acyclic oligoether-substituted quinones 1b, 1c, 2b, and 2c with cyclopentadiene were accelerated by the addition of alkali and alkaline earth metal perchlorates, and scandium trifluoromethane sulfonate (k(c)/k(f) = 1.2-23 for univalent cations, 11-1160 for divalent cations, and 1700-192 000 fo…
The synthesis of poly(L-lactide) (polyLA) end-capped with lactose residue was studied from the standpoint of development of a new bioabsorbable material. After the hydroxyl group of t-butoxycarbonyl(Boc)-aminoethanol was converted to Boc-aminoethanol-OK by using potassium/naphthalene, L-lactide was polymerized in tetr…
Stereoblock polypropylenes have been obtained performing the polymerization of propene at different temperatures in the presence of [1-methyl-1-naphthylethyl-2-inden-1-yl]zirconium(IV) trichloride and methylaluminoxane. The stereoblock microstructure probably arises from to fact that the zirconium complex exists in eq…
ADVERTISEMENT RETURN TO ISSUEPREVNoteNEXTSelf-Alignment of Shortened Multiwall Carbon Nanotubes on Polyelectrolyte LayersBumsu Kim and Wolfgang M. SigmundView Author Information Department of Materials Science & Engineering, University of Florida, 225 Rhines Hall, P.O. Box 116400, Gainesville, Florida 32611 Cite this:…
Micropatterned polymeric diffraction gratings have been fabricated and evaluated as volatile organic chemical sensors. When operated under nonresonant conditions, sensor elements were found to respond in a rapid (response time 5-15 s) and reproducible fashion to each analyte investigated. Relative response magnitudes…
The synthesis of permanently porous, highly cross-linked, poly(methacrylate) resins using supercritical CO 2 is described. The pressure-adjustable solvent properties associated with supercritical fluid solvents are exploited to fine-tune the average pore size and surface area of the materials. It was found that the ma…
The 2-azaphenalenyl radical 2 has been synthesized and characterized by ESR spectroscopy. Variable-temperature ESR measurements were carried out on both the phenalenyl (1) and the 2-azaphenalenyl (2) radicals. The phenalenyl radical 1 has the known propensity to dimerize at temperatures below 20 degrees C, but unexpec…