Materials Literature
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Dimethyltitanocene is an excellent catalyst for the redistribution of alkoxy- and siloxyhydrosilanes. The redistribution reactions of triethoxysilane, diethoxymethylsilane, 1,3,5,7-tetramethylcyclotetrasiloxane, pentamethyldisiloxane, and H—(SiMe 2 O) n —SiMe 2 H (n = 1 to 3) are described. The mechanism of these reac…
SUMMARY The variation in the solubility of aluminium in some acid soils of south‐eastern Australia has been investigated. The hypothesis was that leaching of silicic acid influenced the extent of clay decomposition, and hence aluminium solubility, in accord with Le Chatelier's principle. In lower rainfall areas (<…
Abstract The mechanisms of photooxidation usually envisaged, are perfected by taking into account photoreactions of peroxy radicals. They involve interaction of a peroxy radical with the polymer to yield a hydroperoxy radical and a pair of macroradicals. After peroxidation, this pair will usually undergo bimolecular t…
Quasi-periodicity under certain conditions of the dependence of grating properties on groove depth is explained from the point of view of energy flow distribution (EFD). The formation of curls in flow maps is followed as a function of the groove depth h for two general types of gratings having one or two propagating d…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTStructure and packing in crystalline aliphatic polyestersWen Bin Liau and Richard H. BoydCite this: Macromolecules 1990, 23, 5, 1531–1539Publication Date (Print):March 1, 1990Publication History Published online1 May 2002Published inissue 1 March 1990https://pubs.acs.org/doi…
Abstract Structure‐properties relationships of poly(ether/ester)s (PEEs) 1 based on poly(butylene terephthalate) (PBT) and poly(ethylene glycol) (PEG) are studied. By varying the length of the soft segments (PEG) of molecular weights 600, 1000 and 2000) two series of PEEs are obtained, (i) with constant mole ratio PBT…
Abstract Micropore distribution and effective size of the channels of natural sepiolite from Turkey were measured by the BET method. Before the BET measurement, the samples were treated under a water vapour atmosphere at various pressures to fill progressively the sepiolite micropores with water. The surface areas mea…
Abstract The relation between the structure of the Solution SBR and the dynamic properties of carbon-black-filled SBR vulcanizates have been studied. The results obtained were as follows: 1. The hysteresis of the Solution-SBR vulcanizates was reduced markedly by the introduction of tin—carbon bonds at the polymer chai…
In order to analyze the effects of Al and Fe coatings on mineral grains, montmorillonite (Mt), kaolinite (Kt), and deferrated strongly weathered soils (T6B and T7B) were artificially coated with 2, 6, 10% of Fe or Al hydroxides. Changes in the values of the zero point of charge (ZPC), specific surface area (SSA), and…
Abstract The HALS stabilization mechanisms usually envisaged do not explain the experimental facts. New mechanisms are proposed instead. They include quenching of excited charge‐transfer complexes (CTC) polymer‐oxygen by CTC HALS‐oxygen. In addition, the formation of CTC between peroxy radicals and NH‐HALS is of prime…
In the present paper, a study has been made of carbon dissolution from industrial cokes and specially treated cokes in hot metal. With these results obtained together with earlier investigations, a model is now presented, which attempts to explain carbon pick‐up from coke by hot metal. Factors relating to hot metal, c…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTDirect evidence for transesterification and randomization in a mixture of homopolyesters of poly(4-hydroxybenzoic acid) and poly(6-hydroxy-2-naphthoic acid) above 450.degree.A. Muhlebach, James Economy, R. D. Johnson, T. Karis, and J. LyerlaCite this: Macromolecules 1990, 23…
Abstract Chemical characteristics of glauconite and ferric illite derived from alteration of K-feldspar in three Proterozoic formations of India are studied. The phases show widely varying octahedral and tetrahedral cation contents, but K-content is nearly constant. Co-existence of glauconite and ferric illite is inte…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTSynthesis and characterization of narrow molecular-weight distribution fractions of poly(aryl ether ether ketone)Jacques Roovers, J. David Cooney, and Paul M. ToporowskiCite this: Macromolecules 1990, 23, 6, 1611–1618Publication Date (Print):March 1, 1990Publication History…
Abstract The conditions of polycondensation of dimethyl phosphonate ( 1 ) with different diols were elaborated, leading to polymers with molecular weights up to 3,3 · 10 4 . The novelty of the method is based on a two stage process. In the first stage an excess of 1 was used and short chains with methyl ester end grou…
By using α‐Si 3 N 4 and β‐Si 3 N 4 starting powders with similar particle size and distribution, the effect of α‐β (β') phase transition on densification and microstructure is investigated during the liquid‐phase sintering of 82Si 3 N 4 ·9Al 2 O 3 ·9Y 2 O 3 (wt%) and 80Si 3 N 4 ·13Al 2 O 3 ·5AIN·5AIN·2Y 2 O 3 . When α…
Four methods of force calculation are discussed and compared: equivalent current density, equivalent magnetic charges, the energy principle for both constant and field-dependent permeability, and Maxwell's stresses. Although the formulas for the surface force density are different, it can be shown that the same volume…
Castings to the ASME SA351 CF3 specification used in modern pressurised water reactor nuclear power stations are mainly austenitic, but contain up to 20% ferrite, and as a result are subject to loss of toughness in service at about 300°C. To show adequate end of life toughness, tests are being carried out on material…
Finite difference methods giving approximate solutions to the Cahn–Hilliard equation for phase separation in binary alloys and the results of numerical experiments in two dimensional space are described. Nucleation and growth and spinodal decomposition are considered.MST/1199
The thermodynamic properties of double oxides in rare earth‐transition metal (V and Mn)‐oxygen ternary systems have been collected and evaluated to examine their stability using chemical potential diagrams plotted as log (α A /α B ) vs log ( P (O 2 )). The thermodynamic regularities of perovskites, pyrochlores, and ot…