Materials Literature
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Abstract Pyrrole was found to polymerize electrochemically in a smooth and facile way when the immediate vincinity of the anode is at a pH of 3 ([H + ] = 10 −3 mol/dm 3 ). The polymerization is inhibited by the presence of a H + scavenger, di‐ tert ‐butylpyridine. Polymerization of pyrrole in a buffered solution of pH…
Treatment of Zr(NEt2)4 with the free-base porphyrins 5,10,15,20-ttraphenylporphyrin (H2TPP) or 2,3,7,8,12,13,17,18-octaethylporphyrin (H2OEP) gives the transition-metal bis(porphyrinato) complexes Zr(TPP)2 and Zr(OEP)2. The hafnium analogue Hf(OEP)2 may be prepared similarly from Hf(NEt2)4. The complexes have been cha…
Dimers with very different RuRu bond lengths and RuClRu bond angles—deformation isomers—are present in equal parts in crystals of the title compound. Solid-state NMR investigations show that the isomer 1 a with the shorter RuRu distance (2.93 Å) is diamagnetic, that with the longer distance (3.75 Å, 1 b), on the o…
Sessile drop studies of molten aluminum on single‐crystal sapphire substrates were conducted to investigate the effects of atmosphere on contact angle, substrate reactions, and interfacial crystal growth. Unlike previous investigations performed briefly in a vacuum environment in a temperature range within 600°C of th…
Abstract The microhardness ( H ) of poly(ethylene terephthalate) (PET) containing catalysts, as well as of PET without catalysts has been investigated. Two types of morphologies have been examined: (a) structures where spherulitic growth is incomplete, resulting from a primary crystallization from the glassy state and…
The occurrence of a reversible phase transformation from a rhombohedral crystalline structure to a perfect quasicrystalline state of chemical composition Al63·5Fe12·5Cu24 has been studied by transmission electron microscopy. Both direct in situ heating experiments and thermal treatments of bulk dodecahedral particles…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTA spectroscopic study of phase-transition kinetics in syndiotactic polystyreneNicholas M. Reynolds, Howard D. Stidham, and Shaw Ling HsuCite this: Macromolecules 1991, 24, 12, 3662–3665Publication Date (Print):June 1, 1991Publication History Published online1 May 2002Publish…
We report a neutron diffraction study of the liquid structure of YCl 3 and combine the structural data with macroscopic melting and transport data to contrast the behaviour of this molten salt with those of SrCl 2 , ZnCl 2 and AlCl 3 as prototypes of different melting mechanisms for ionic materials. A novel melting me…
In Parts I and II, the structure of small-scale yielding fields of interface cracks were described in the context of small strain plasticity and J2 deformation theory. These fields are members of a family parameterized by the plastic phase angle ξ which also determines the shape or phase of the plastic zone. Through f…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTStrong ferromagnetism between copper(II) ions separated by 6.7 .ANG. in a new phthalato-bridged copper(II) binuclear complexSaleh K. Shakhatreh, Evangelos G. Bakalbassis, Irene Bruedgam, Hans Hartl, Jerzy Mrozinski, and Constantinos A. TsipisCite this: Inorg. Chem. 1991, 30,…
We have undertaken a new and more detailed Fourier‐transform infrared (FTIR) spectroscopic study of α ‐lactalbumin (in D 2 O solution) aimed at correlating its secondary structures to observed Amide I’ infrared bands. The spectra reported here were interpreted in light of the recently determined crystal structure of α…
The local chain dynamics of bulk amorphous polymers has been studied by means of molecular dynamics simulation in the vicinity of the glass transition temperature Tg. Two models of polymers are used, one mimicking a polyethylene chain and the other a hypothetical freely-rotating chain, both of infinite chain length. T…
Communication: Triplet electron‐transfer salts are predicted to exhibit bulk ferromagnetic behavior at higher temperatures than their singlet analogues. To test this expected trend, the title compound, which is isostructural with [FeCp ] ⊙⊕ [TCNE] ⊙⊖ (Cp * = pentamethylcyloopentadienide; TCNE = tetracyanoethylene) whi…
Ethylene diamine tetra acetic acid (EDTA) is a versatile complexing agent and is being employed in decontamination formulations. The dilute chemical decontamination (DCD) process employs ion exchange resins for regeneration of complexants, collection of metal ions/active isotopes and for removal of the decontaminating…
Abstract The resonance Raman spectra of side‐on type dioxygen adducts of Mn(TMP), Mn(TPP) and Mn(OEP), where TMP, TPP and OEP denote the dianions of tetramesityl‐, tetraphenyl‐ and octaethyl‐porphines, respectively, were measured in O 2 ‐Ar(1 : 30) matrices at ca. 15 K. The bands near 990, 710 and 430 cm −1 were assig…
Contact angle measurements have been widely used1–6 to calculate the values of the dispersion force, γ d s , and polar force, γ p s , components to the total surface free energy of a material using a derivation originally proposed by Kaelble.2 In this analysis a pair of simultaneous equations is derived which for two…
Abstract Crystallization kinetics of short glass and carbon fiber composites of poly(ether ether ketone) (PEEK) under melt‐strain conditions have been obtained for the first time, using in ‐ situ wide angle X‐ray scattering, and have been correlated to a model based on the Avrami equation in order to enable minimizati…
Abstract Annealing poly(ethylene terephthalate) (PET) at high temperature results in a crystalline phase stable to 10°C higher than the temperature previously regarded as the equilibrium melting point. Melting temperatures as high as 289°C can be attained, which is equivalent to the equilibrium melting point determine…
Solutions of TeO 2 (0.001 M) in HCl over a range of concentrations are shown to contain TeCl 2 (OH) 2 in addition to TeCl 6 2− and TeCl 4 (OH) − . The hydrolysis constants for TeCl 6 2− and TeCl 4 (OH) − have been determined from a reconsideration of earlier UV-visible spectrophotometric results (1)[Formula: see text]…
A description of the design and setup of an experimental technique for measurement of the response function in shear sensitive liquid crystals has been reported. Utilizing the selective reflection characteristics of cholesteric liquid crystals, the method is capable of measuring the delay, rise, and relaxation times i…