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Abstract Furan‐based diisocyanates and diamines were prepared unambiguously as potential monomers for polyurethane and polyamide production, starting from methyl furoate and furfurylamine, respectively. The syntheses were optimized and the product identity was confirmed by elemental analysis, IR and NMR spectroscopy,…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTPolarized electronic spectra of dirhodium(II) tetraacetateVincent M. Miskowski, William P. Schaefer, Behzad Sadeghu Sadeghi, Bernard D. Santarsiero, and Harry B. GrayCite this: Inorg. Chem. 1984, 23, 8, 1154–1162Publication Date (Print):April 1, 1984Publication History Publi…
Like many other eubacteria, cultures of Escherichia coli accumulate cyclopropane fatty acids (CFAs) at a well-defined stage of growth, due to the action of the cytoplasmic enzyme CFA synthase. We report the isolation of the putative structural gene, cfa, for this enzyme on an E. coli-ColE1 chimeric plasmid by the use…
The densification of alumina powders prepared to have a bi‐modal particle‐size distribution with a coarse‐to‐fine particle‐size ratio of ≊ 10 can be predicted to a first approximation if the densification of the fine and coarse powders is known. Deviations from model prediction were attributed to compositional heterog…
Most transition-metal magnets, although itinerant in nature, do not undergo large volume contractions on passing from the magnetic to the non-magnetic state. Such a contraction might be expected because of the very large internal magnetic pressure which has been calculated to exist in these magnets at zero temperature…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTNew approach to the problem of elastic scattering from a mixture of homopolymers in a concentrated solutionHenri Benoit and Mustapha BenmounaCite this: Macromolecules 1984, 17, 4, 535–540Publication Date (Print):April 1, 1984Publication History Published online1 May 2002Publ…
Abstract In this study, three different polymers were blended: a racemic PMEPL (PMEPL‐RAC) which consists of a random distribution of repeat units of R or S configurations, an isotactic PMEPL made of repeat units of S configuration [PMEPL‐S(−)], and a second isotactic PMEPL made of repeat units of R configuration [PME…
Abstract This paper discusses the results of a detailed study of the relationships between molecular orientation, physical properties, and molecular weight of polyethylene terephthalate (PET), and their dependence on orientation variables. The molecular weight range of the samples used in this study included weight av…
A new type of electret transducer based on the use of an SiO2 backplate electret is presented. Frequency-response measurements on a prototype device demonstrate the feasibility of the design. Possible improvements and the main advantages of the new transducer principle are discussed.
Views Icon Views Article contents Figures & tables Video Audio Supplementary Data Peer Review Share Icon Share Twitter Facebook Reddit LinkedIn Tools Icon Tools Reprints and Permissions Cite Icon Cite Search Site Citation Yasufumi Otsubo, Kaoru Umeya; Rheological Properties of Silica Suspensions in Polyacrylamide Solu…
Ferroelectric tetragonal tungsten bronze (T.B.) family single crystals, e.g., SBN, BSKNN, KLN, SKN and PBN, have been grown and their ferroelectric properties have been investigated. The results show that the dielectric, piezoelectric, and electromechanical coupling coefficients are significantly large for these cryst…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTHydrophilic polyurethane networks based on poly(ethylene oxide): synthesis, characterization, and properties. Potential applications as biomaterialsYves Gnanou, Gerard Hild, and Paul RemppCite this: Macromolecules 1984, 17, 4, 945–952Publication Date (Print):April 1, 1984Pub…
Soda‐silica and soda‐lime‐silica glasses were prepared with varying amounts of Si 3 N 4 , to produce oxynitride glasses with nitrogen contents up to 3.23 mol%. The glasses were analyzed by Fourier transform infrared spectroscopy and X‐ray photoelectron spectroscopy, and evidence for the formation of tricoordinated nit…
Abstract Solid-state 29 Si and 27 Al NMR spectroscopy with magic-angle spinning was used to study two smectites, two illites and a vermiculite. 27 Al NMR was able to directly observe the coordination of aluminium. 29 Si NMR was sensitive to both the chemical nature of the interlayer species and the presence of alumini…
Four series of polyurethane elastomers were synthesized using diphenylmethane diisocyanate (MDI) and castor oil as the polyol. Two types of MDI (crude and distilled) were used. The temperature of reaction and the effect of excess isocyanate above stoichiometric were also varied. The structure of the polyurethanes was…
The vacuoles of Neurospora crassa, grown in minimal medium, contain a 1:1 ratio of basic amino acids and phosphate, the latter in the form of long-chain, inorganic polyphosphate-P. Vacuoles isolated from cells depleted of polyphosphate retain basic amino acids despite the absence of over 90% of their polyphosphate. Th…
Abstract 1 H and 13 C NMR studies on magnesium anthracene ⋅ 3 THF ( 2a ), which can be recrystallized from THF, indicate that magnesium has the strongest interaction with the 9,10‐positions of anthracene. While the rate of formation of 2a from magnesium and anthracene in THF at 60°C is proportional to both anthracene…
The glass‐transition temperature ( T g ) is a fundamental property of all organic binders, It is illustrated with polyethylene glycol (PEG)‐plasticized polyvinyl alcohol (PVA) binder systems that densification is enhanced when the binder T g , is below the pressing temperature. This is a result of the increased deform…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTElectronic structures of transition-metal tetrachalcogenides (MSe4)nI (M = Nb, Ta)Pascal Gressier, Myung Hwan Whangbo, Alain Meerschaut, and Jean RouxelCite this: Inorg. Chem. 1984, 23, 9, 1221–1228Publication Date (Print):April 1, 1984Publication History Published online1 M…
The temperature dependence of the pyroelectric coefficient γd of (Na½Bi½)TiO3 ceramics has been measured. It was found that this crystal is a perspective material for using as a sensitive element of the pyroelectric radiation detectors steadily working in the temperature range of ∽ 20—60°C (γd = 2.5 ' 10-8C cm-2 °C-1;…