Materials Literature
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( S )-((2-Methylbutyl)thio)hydroquinone was prepared from benzoquinone and ( S )-2-methylbutyl mercaptan. One series of cholesteric copolycarbonates was prepared from this chiral hydroquinone, methylhydroquinone, and 4,4‘-dihydroxybiphenyl by interfacial polycondensation with diphosgene. All copolycarbonates were nonc…
The influence of microstructure and inclusion on the susceptibility to stress oriented hydrogen induced cracking, SOHIC, or type I sulfide stress cracking, SSC, was investigated for two kinds of line pipe steels which have the different susceptibility to SOHIC. The steel plates, produced by accelerated cooling after c…
Addition of natural clay materials in intumescent polypropylene-based formulations (additive: ammonium polyphosphate and pentaerythritol) leads either to a decrease or to an increase of their fire retardant performances versus the chemical or the physical characteristics of the clay materials. A study of the factors a…
The steps required for the development of a Zr-2.5Nb pressure tube with a 30-year service life are outlined. The life-limiting factors of fracture and deformation are described, and progress towards closing the gap between the properties required to meet the target lifetime and the behavior of current materials is sum…
A diamond-bearing eclogite has been studied using industrial high-energy computed tomography and volume visualization techniques. Using this non-destructive technique, in which distinction between phases is based on density differences, seven diamonds (five completely enclosed in the rock) have been isolated and viewe…
The surface morphology of thin molten films of phase separating mixtures of poly(ethylenepropylene) (PEP) and perdeuterated poly(ethylenepropylene) (dPEP) of the critical composition were investigated using scanning force microscopy. Volume fraction versus depth profiles were also obtained using time-of-flight forward…
The synthesis of a new class of poly(aryl ether chalcone)s is described by a polycondensation reaction of 4,4‘-difluorochalcone with various bisphenols in the excess anhydrous potassium carbonate in sulfolane/toluene mixture solvent. Fluoride atoms located at the para position of the chalcone moiety were found to be v…
Edible films, coatings and biodegradable packagings produced from biological materials offer numerous advantages over other conventional synthetic packaging materials. Potential applications of edible films are numerous (internal moisture or solute barriers of heterogeneous foods, individual protection of food pieces,…
ADVERTISEMENT RETURN TO ISSUEPREVCommunication to the...Communication to the EditorNEXTChanging Cellulose Crystalline Structure in Forming Wood Cell WallsYutaka Kataoka and Tetsuo KondoView Author Information Forestry and Forest Products Research Institute, P.O. Box 16, Tsukuba Norin, 305 JapanCite this: Macromolecule…
This paper examines the properties of a defected zeolite matrix with the faujasite structure, promoted with gallium oxide. The fate of β-Ga 2 O 3 loaded onto ultrastable faujasite is followed by XRD, FT IR, and laser Raman spectroscopies, and also by solid-state multinuclear NMR. Gallium(III) oxide is reduced after th…
Deprotonation of p-hydroxybenzoate to the phenolate and reprotonation of the hydroxylated dienone intermediate to form the product are essential steps in the reaction catalyzed by p-hydroxybenzoate hydroxylase (PHBH). The mechanism by which protons are transferred in these reactions is not obvious, because the substra…
Direct evidence of local structural inhomogeneity and nonuniform doping-level distribution in conducting polymer film has been obtained using Kelvin probe force microscopy (KFM) and atomic force microscopy (AFM). The KFM data suggests that the polymer consists of grains that constantly differ in work function and thus…
Polarized Fourier transform infrared microscopy (FT-IRM) was used to assess the orientation of mineral and matrix components of the normally calcified turkey leg tendon. Two groups of tendon, < 16 weeks of age (young) and > 60 weeks of age (old), were analyzed. Linear sequences from calcified, non-calcified, and trans…
Abstract Poly(aryl ether ketone ketone)s (PEKKs) are prepared via a Friedel‐Crafts acylation reaction with diphenyl ether and terephthalic acid (T) and/or isophthalic acid (I). The crystal structure, polymorphism and morphology of three PEKK homopolymers have been investigated using transmission electron microscopy (T…
Molecular geometries, dipole moments, polarizabilities and first-order hyperpolarizabilities for five classic donor−aromatic π system−acceptor NLO chromophores were calculated, using semiempirical methods (PM3), in both vacuum and solvent environments. Solvent effects on the computed molecular geometries were found to…
We present results of the energies of formation and hydration of small clusters and rings containing Si and Al; the results provide a rationalisation of Lowenstein's rule in terms of the energetics of species containing Al–O–Al bridges.
A homogeneous catalytic system based on a suitable Ni(II) diimine derivative and methylaluminoxane affords predominantly syndiotactic polypropylene at subambient temperatures. The polymer microstructure is that expected for a “chain-end” mechanism of steric control. NMR analysis of polymer samples carrying selectively…
The luminescence properties of Bi3+, Eu3+, Dy3+ and energy transfer from Bi3+ to Dy3+ and Eu3+ have been studied in two modifications of Y2SiO5(low-temperature X1 type and high-temperature X2 type) and discussed in relation to their crystal structures. The Bi3+ ion luminesces in the blue region of the spectrum in X1-Y…
Beryllium oxide(BeO)-doped (0.3, 0.6, 0.9, 1.2 and 13.6 wt%) UO2 pellets were fabricated to evaluate the effects of BeO precipitate shape on thermal conductivity. Precipitate distributions were of two types: BeO precipitated almost continuously along a grain boundary (designated BeO continuous type) and spherical BeO…
A heterogeneous reactor model was developed describing kinetic experiments on the heterogeneously catalyzed oxidative coupling of methane in a laboratory fixed-bed reactor. The catalyst produces radicals which react further through gas-phase reactions in the pores of the catalyst and in the interstitial phase. The rea…