Materials Literature
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The glass-transition temperatures (T g ) of thirty-one polyamide homopolymers and copolymers of widely differing molecular structure have been determined by differential scanning calorimetry or, as fibers, by dynamic tensile property measurements, and the results have been related to molecular structure. The effect of…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTPhosphorus-nitrogen compounds. 31. Crystal and molecular structure of a platinum-cyclophosphazene complex: cis-dichloro[octa(methylamino)cyclotetraphosphazene-N,N'']platinum(II)Robert W. Allen, John P. O'Brien, and Harry R. AllcockCite this: J. Am. Chem. Soc. 1977, 99, 12, 3…
The resistivities and activation energies of borate glasses containing oxides of both V and Fe, and both V and Cu are lower than those of glasses containing the same amounts of each TM oxide separately. Optical and ESR spectra suggest that the proportions of ions in reduced valence states are not greatly affected by m…
A monobenzoporphyrin has been prepared from porphyrin derivatives containing a fused cyclo-hexanone ring. The cyclohexanone system can be constructed either before or after the porphyrin macrocycle has been synthesized. The spectroscopic properties of the monobenzoporphyrin are described and these support the proposal…
Abstract X‐ray diffraction scans and infrared absorption spectra for the C‐CI stretching region were obtained for a highly syndiotactic poly(vinyl chloride) (PVC) sample made by the urea clathrate method. When the polymer was annealed at a series of increasing temperatures up to 180°C, x‐ray diffraction measurements s…
Abstract Protein complexes of smectites in soils are difficult to detect if the usual smectite tests show no peculiarities. Andalusian black earths are typical examples. Investigation of the alkylam-monium derivatives, however, allows detection of adhered macromolecules which might be protein-like although this cannot…
Abstract Experimental carbonate cementation under various conditions of temperature, solution composition and physical environment of cementation resulted in cements analogous to their natural counterparts reported in the literature. Scanning electron microscopic (SEM), optical microscopic, and chemical analyses of th…
A folate-binding protein has been solubilized from Lactobacillus casei by treatment of membrane preparations with Triton X-100 in the presence of [3H]folate. The protein-folate complex was purified 100-fold and recovered in a 22% yield by adsorption and elution from microgranular silica (Quso G-32), followed by passag…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTExchange interactions in halide-bridged chains of copper(II). Cu(Rpy)2X2Van H. Crawford and William E. HatfieldCite this: Inorg. Chem. 1977, 16, 6, 1336–1341Publication Date (Print):June 1, 1977Publication History Published online1 May 2002Published inissue 1 June 1977https:…
Crosslinked polyacrylamide gels formed by copolymerisation of acrylamide and N,N′-methylenebisacrylamide in aqueous solution have been characterised by viscoelastic measurements in the frequency range 0.05–150 Hz. These data are consistent with the model, derived from permeability data, of a non-draining central core…
This paper describes preliminary pyroelectric and piezoelectric results obtained with commercial films of nylon 11. The results of dielectric-constant measurements in the temperature range 20–130 °C are also presented. Nylon 11 films show quite high pyroelectricity and the evidence indicates that there is probably dip…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTAn approximate expression of the electrostatic molecular potential in terms of completely transferable group contributionsRosanna Bonaccorsi, Eolo Scrocco, and Jacopo TomasiCite this: J. Am. Chem. Soc. 1977, 99, 14, 4546–4554Publication Date (Print):June 1, 1977Publication H…
Advantages in using the pyrophosphate complex of trivalent managanese over the sulfate complex as initiator for graft copolymerization onto starch are discussed. The first successful attempts to graft copolymerize acrylonitrile, methyl methacrylate, and acrylamide to starch and starch derivatives are described using m…
A computer simulation of the insulator surface charging in vacuum under the application of a high voltage, is presented for alumina (A1203) insulator and for alumina insulators coated with cuprous oxide (Cu2O) and chromium oxide (Cr2O3). It is shown that the mode of surface charge distribution is dependent on the seco…
We have determined the amounts of a number of small molecules and enzymes in the mother cell compartment and the developing forespore during sporulation of Bacillus megaterium. Significant amounts of adenosine 5'-triphosphate and reduced nicotinamide adenine dinucleotide were present in the forespore compartment befor…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTStructure of the catalytic site of polymer-bound Wilkinson's catalyst by x-ray absorption studiesJoseph Reed, P. Eisenberger, Boon-Keng Teo, and B. M. KincaidCite this: J. Am. Chem. Soc. 1977, 99, 15, 5217–5218Publication Date (Print):June 1, 1977Publication History Publishe…
Abstract Nine synthetic Na-saponites with charge densities varying between 0.33 and 1.0 have been prepared. Their swelling properties and structural organization in water, ethylene glycol and glycerol show discontinuities in the physico-chemical behaviour of these samples. The layer charge densities caused changes in…
Abstract The collagen of bovine striated muscle has been shown to be comprised of three genetically distinct types of collagen, the proportions of which vary from the tendon to the endomysium. Despite the variation in genetic type all three collagens are stabilised by lysine‐derived cross‐links. It is proposed that th…
Abstract The equivalent dipole model of the ring current shift in benzene is shown to be equivalent to that of the well‐known two current loop calculation. A network model of the ring current effect in the porphyrin system is described, using the double–dipole approximation, to give a calculation of the ring current s…
We report measurements of the hydrogen concentrations and densities of amorphous silicon films prepared from glow discharge plasmas of silane. Quantitative results are obtained from the resonant nuclear reaction 15N+1H→12C+4He+γ by counting the emitted γ rays. Mass spectrographic analysis of the gases evolved upon hea…