Materials Literature
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Abstract It has been demonstrated that the poly(vinyl fluoride) film can be fluorinated by exposing the polymer to an environment of fluorine under atmospheric pressure and at ambient temperature. Fluorine content, infrared spectra, thermal properties, and solubilities in the polar solvents were investigated for the f…
The rate of decomposition of PVDC is sensitive to differences in the method of preparation of the polymer. Polymers prepared by mass polymerization of very pure monomer were most stable. Emulsion polymerized PVDC degraded the fastest. The activation energy for the latter was 34.4 kcal/mole. Over the range of 130°–190°…
Ultrasonic interferometry was used to measure elastic‐wave velocities and moduli in six Na 2 O‐TiO 2 ‐SiO 2 glasses; three glasses contained 20 mol% TiO 2 and three 25 mol% TiO 2 . The elastic moduli and their pressure derivatives varied systematically with the SiO 2 /Na 2 O molar ratio of the glasses. In the group of…
Estimates have been made from electrode potential measurements of the composition and stability constants of the complexes formed by tin with citric, malic, oxalic and tartaric acids in solutions of the concentration range appropriate to canned fruits. The stability constants suggested are highest for oxalic acid, smu…
A neutron diffraction study of orthorhombic L‐histidine, C 6 H 9 N 3 O 2 , has been carried out. The structure belongs to space group P2 1 2 1 2 1 , with four molecules per unit cell. Cell parameters are: a = 5.175 (5) Å, b = 7.315 (8) Å and c = 18.75 (2) Å. A total of 618 unique reflections were used in the least‐squ…
β eucryptite, Li 2 O · Al 2 O 3 · 2SiO 2 , has a high-quartz-like structure. It crystallizes in the space group P 6 2 22. X-ray diffraction photographs of single crystals show, besides the main reflections of a high-quartz-like subcell, superstructure reflections which lead to doubling of the lattice constants of the…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTOut-of-plane interactions in parallel-planar copper(II) dimers. Structure and magnetic properties of dibromobis(2-methylpyridine)copper(II)Phirtu Singh, David Y. Jeter, William E. Hatfield, and Derek J. HodgsonCite this: Inorg. Chem. 1972, 11, 7, 1657–1661Publication Date (P…
One unsymmetricly p,p′-disubstituted trans-stilben and more than 60 new phenylbenzoates are described (Tab. 1). These compounds show partly enantiotropic, partly monotropic nematic behaviour. Some low melting substances and especially eutectic mixtures of this class of compounds are useful as room-temperature nematic,…
The continuum approximation replaces a group of discrete dislocations by a continuous dislocation density. It is shown that this formalism possesses similarity solutions of the equations of motion with an arbitrary power law stress-velocity relationship in parallel with the similarity motions of the discrete group. Th…
The superstructure of β eucryptite shows an alternating sequence of Si and Al layers. For a Si-Al ratio of 1:1 only in this arrangement each AlO 4 or SiO 4 tetrahedron can be surrounded by four SiO 4 or AlO 4 tetrahedra, respectively. The Li atoms also have an ordered distribution. The following mean values of bond di…
The pair-production energy Ep for free carriers in silicon and germanium is measured using low-energy electrons (10–24 keV) as ionizing sources. The number of carriers generated is measured via a modified Haynes-Shockley technique with a pn junction collector and a super-posed drift field. Experimental values for Ep o…
The pitting of pure iron, and its alloys with chromium and copper, in neutral chloride solutions, has been studied using microscopy and time-lapse photography, and measurements have been made of local variations of pH value and electrode potential using micro-electrodes. Primary pitting at a few discrete points is fol…
Abstract Secondary nucleation in the potassium sulfate‐water system occurs by micro‐attrition processes over the entire 1.3‐26 μ size range of this study. Experimental nucleation rates were correlated with power‐law kinetics expressions in terms of supersaturation, the fourth moment of the parent seed‐crystal distribu…
Abstract Two types of emulsion‐grade polytetrafluoroethylene particles have been studied. We refer to these as ribbons and rods. The ribbons consist of very thin ribbons or lamellae folded upon themselves a number of times. In typical emulsion‐grade material prepared at Allied Chemical, the unraveled ribbon measures a…
A technique is described for measuring the rate of photobleaching of anisotropic dye molecules in solid polymer matrices. Three dyes of different classes in two matrices (PMMA and epoxy resin) show bleaching rates that differ by a factor of 20. The bleaching rate is linearly proportional to the intensity of incident r…
The crystal structure of the mineral analcime, NaAlSi 2 O 6 · H 2 O, known from x-ray analysis to approximate closely to the cubic space-group symmetry Ia 3 d , has been examined by neutron diffraction. Intensity data from a single crystal were collected for one octant so as to be representative of cubic and some lowe…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTPhthalocyanine derivatives from 1,2,4,5-tetracyanobenzene or pyromellitic dianhydride and metal saltsDavid R. Boston and John C. Bailar Jr.Cite this: Inorg. Chem. 1972, 11, 7, 1578–1583Publication Date (Print):July 1, 1972Publication History Published online1 May 2002Publish…
Any type of irradiation that displaces atoms can produce voids in non-fissile metals and alloys, consequent swelling and mechanical property effects becoming important in fast reactor design and operation. The basic reason for void formation is preferential absorption of interstitials at dislocations. Void growth depe…
Reaction of molecular oxygen as a modulated molecular beam with the basal plane of pyrolytic graphite is investigated. The graphite surface participates in the reaction in an unusual fashion. Oxidation tends to create a highly reactive surface while thermal annealing tends to deactivate the surface. The imbalance of t…
Abstract The two endotherms found during DSC analysis of annealed or drawn poly(ethylene terephthalate), PET, are discussed in greater. detail. Earlier workers proposed that the endotherms were the result of separate morphologies, i.e., extended‐chain and folded‐chain crystals, but more recently Roberts and others hav…