Materials Literature
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The wet oxidation of organic compounds composed only of C, H, and O, dyes, amides, and water-soluble polymers is discussed to clarify the basic nature of this process. The reactivity of the organic compounds composed of C, H, and O, dyes, and some amides was correlated well with their carbon content in the molecule (C…
A series of new hydrolytically stable poly(carbobetaine)s with varying distance between the ammonium and the carboxylate group was synthesized, excluding the presence of residual salt in the polymers, together with cationic and sulfobetaine analogues. The poly(carbobetaine)s show improved solubility compared to analog…
2,3-O-Carboxymethylcellulose (CMC) samples of different degree of substitution (DS) were synthesized via 6-O-(4-monomethoxytriphenylmethyl)cellulose under a variety of conditions and with different carboxymethylating agents. The highest DS of carboxymethyl groups of 1.7 was reached with sodium monochloroacetate in dim…
Binary blends of polyamide 6 (PA-6) and the copolymer styrene−maleic anhydride (SMA) have been prepared via melt extrusion. The amino end groups of PA-6 and the anhydride groups of SMA react with each other during melt blending; this leads to the formation of a comblike graft copolymer at the interface between PA-6 an…
The addition of leucine induced activation of p70S6k in amino acid-depleted H4IIE cells. Whereas the activation of p70S6k by leucine was transient, the complete amino acid stimulated p70S6k more persistently. The effect of leucine on p70S6k was sensitive to rapamycin, but less sensitive to wortmannin. Using various am…
Bipyridine, a workhorse among the ligands of complex chemistry, can be reduced with sodium to its dianion. Depending on the solvent different sodium salts crystallize: from dimethoxyethane/toluene a polymer, from tetramethylethylenediamine/benzene a lipophilically wrapped [Na14O]12+ cluster, and from pure pentamethyld…
This paper discusses a new class of maleic anhydride modified PP polymers (PP-MA), having a relatively well-defined molecular structure. The chemistry involves the borane-terminated PP intermediate that is prepared by hydroboration of the chain-end unsaturated PP. The borane group at the chain end was selectively oxid…
Accurate models of protein diffusion are important in a number of applications, including liquid−liquid phase separation and growth of protein crystals for X-ray diffraction studies. In concentrated multicomponent protein systems, significant deviations from pseudobinary behavior can be expected. Rayleigh interferomet…
Two novel phenomena in a weakly coupled granular superconductor under an applied stress are predicted which are based on recently suggested piezophase effect (a macroscopic quantum analog of the piezoelectric effect) in mechanically loaded grain boundary Josephson junctions. Namely, we consider the existence of stress…
The equilibrium phase diagram of boron nitride thermodynamically calculated by Solozhenko in 1988 has been now refined on the basis of new experimental data on BN melting and extrapolation of heat capacities of BN polymorphs into high-temperature region using the adapted pseudo-Debye model. As compared with the above…
A diverse range of reaction conditions for the MacDonald-type 2 + 2 condensation of a 5-substituted dipyrromethane and an aldehyde has been studied with the goal of eliminating acid-catalyzed polypyrrolic rearrangement reactions in the synthesis of trans-porphyrins. A rapid screening method based on laser desorption m…
Ethylene pressure has been used to control the competition between isomerization (chain walking) and monomer insertion processes for ethylene coordination polymerization catalyzed by a palladium-alpha-diimine catalyst. The topology of the polyethylene varies from linear with moderate branching to "hyperbranched" struc…
Recent computational studies of models for manganese oxides have revealed a rich phase diagram, which was not anticipated in early calculations in this context performed in the 1950s and 1960s. In particular, the transition between the antiferromagnetic insulator state of the hole-undoped limit and the ferromagnetic m…
Several smectites were pillared with metal complexes, such as the trimeric cobalt cation [Co 3 (OC 2 H 4 NH 2 ) 6 ] 3+ and its divalent analogue [Co 3 (OC 2 H 4 NH 2 ) 6 ] 2+, containing clusters of one to three cobalt cations separated by bridging ligands. In pillared interlayered clays (PILC) prepared by reacting Na…
The preparation and properties are described of complexes resulting from the mono- and diprotonation of the [Co(4)O(4)](4+) unit to give products containing [Co(4)O(3)(OH)](5+) and [Co(4)O(2)(OH)(2)](6+), respectively. Treatment of [Co(4)O(4)(O(2)CC(6)H(4)-p-OMe)(2)(bpy)(4)](2+) (bpy = 2,2'-bipyridine) in MeCN with 70…
In this paper, we report a simple and clean method of producing uniform nonaqueous gold colloids by the chemical reduction of chloroauric acid (HAuCl 4 ) using the oxygen-free organic supporting medium formamide itself as reducing agent in the presence of the stabilizer poly(vinylpyrrolidone) (PVP). The reduction of H…
At the Fifth Chemical Congress of North America held at Cancun in November, 1997, a broad definition of the fields to be covered in the symposium on natural polymers as advanced materials was given. Included were recent developments and future prospects for natural polymers in uses ranging from detergents, adhesives,…
ADVERTISEMENT RETURN TO ISSUEPREVCommunicationNEXT"Melting Transition" of a Quantum Dot Solid: Collective Interactions Influence the Thermally-Induced Order−Disorder Transition of a Silver Nanocrystal SuperlatticeBrian A. Korgel, Nelsi Zaccheroni, and Donald FitzmauriceView Author Information Department of Chemical En…
This article summarizes several technical studies reported in the literature on catalytic conversion technology to control pollution due to automotive exhausts with specific focus on NOx reduction. While simple theoretical reactions are stated, the review concisely presents the various techniques available with their…
Polyaddition of isophorone diisocyanate to poly(oxypropylene)glycol (PPG)-Based waterborne polyurethane (WPU) synthesized by a modified acetone process was performed. Fourier transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS), differential scanning calorimetry (DSC), and impedance spectrosc…