Materials Literature
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Ab initio calculations were carried out on zinc-porphyrins complexed to several amines: N-(3,5-dimethyl-pyridin-4-yl)-formamide, 1,4-diazabiciclo[2.2.2]octane (DABCO), and 1-azabiciclo[2.2.2]octane (quinuclidine). The proton chemical shifts of these complexes were calculated ab initio at the GIAO-HF/6-311G//HF/3-21G l…
*Reprinted from Star and Hyperbranched Polymers; Mishra, M.K., Kobayashi, S., Eds.; Marcel Dekker, Inc.: New York; 1999, 201–238.
Coumarin-endcapped tetrabranched liquid copolymers composed of epsilon-caprolactone and trimethylene carbonate (TMC), prepared using pentaerythritol or four-branched poly(ethylene glycol) (PEG) as an initiator, were ultraviolet irradiated to produce photocured solid biodegradable copolymers. The hydrolytic degradation…
The objective of this article is to overview processes of mechanical alloying/milling (MA/MM), and their modifications applied to produce nanostructured single- and multi-phase intermetallics, and their composites, for hydrogen storage. In the most typical processing, MA is used as a preliminary step in synthesizing a…
*Reprinted from Supramolecular Polymers; Ciferri, A., Ed.; Marcel Dekker, Inc.: New York; 2000, 565–613.
Silicas with large (about 10 nm in diameter), uniform, cage-like pores were synthesized from sodium silicate and poly(ethylene oxide)−poly(butylene oxide)−poly(ethylene oxide) B50-6600 triblock copolymer template (EO 39 BO 47 EO 39 ) under acidic conditions. The synthesis procedure was analogous to that reported by ot…
A series of subphthalocyanine-C(60) dyads in which the two subunits are placed at different distances have been prepared and their electrochemical properties measured. Photophysical measurements reveal energy transfer events following the initial photoexcitation of the subphthalocyanine chromophore.
Close contacts between chalcogen atoms in cyclic dienes and diynes are used to create columnar structures in the solid state. Rigid and fairly planar cycles with chalcogen centers are the preconditions for forming those columnar structures.
Intercalation of seven types of cationic surfactants, including polyfluorinated surfactants, into a cation-exchangeable clay mineral, saponite, was investigated. All of the surfactants were found to intercalate in amounts exceeding the cation exchange capacity (CEC). This tendency was more evident in the cases of the…
In the present review article, recent research work on polyaniline-type conducting polymers has been surveyed. Research and development work has been reviewed with special interest in chemical, electrochemical, doping processes, and polyaniline-based composite processes. Process development with high accuracy of produ…
Abstract Styrene‐butadiene rubber (SBR) vulcanizates with graded network‐chain densities in the thickness direction were prepared by layering and heat pressing the compounding sheets. The effect of the gradient of network‐chain density on the mechanical properties of the graded rubber vulcanizates was investigated in…
Abstract The effect of the addition of 5 and 10 phr of unsaturated polyester resin (UPE) on the compatibility and physicomechanical properties of styrene–butadiene (SBR) and acrylonitrile–butadiene (NBR) rubber blends was studied. Differential scanning calorimetry (DSC), scanning electron microscopy (SEM), electrical,…
Polycrystalline samples of BaLaMnO4, oxygen deficient and oxygen excess BaLaMnO4 ± δ and the solid solution BaxSr1 − xLaMnO4 have been prepared and investigated. Magnetic susceptibility, powder X-ray diffraction and variable temperature powder neutron diffraction data are presented for these compounds. BaLaMnO4 and Ba…
Abstract This paper deals with the influence of interface between polyethylene and semiconducting electrode on the space charge formation and electrical breakdown. Low‐density polyethylene (LDPE) films attached with different semiconducting electrodes were subjected to the DC breakdown test, and corresponding space ch…
The critical divergence of the smectic-order correlation lengths parallel and perpendicular to the director, ${\ensuremath{\xi}}_{\ensuremath{\parallel},\ensuremath{\perp}}$, and the susceptibility, ${\ensuremath{\sigma}}_{0}$, near the nematic-to-smectic-A phase transition has been measured in a 5 T magnetic field. T…
Abstract Free‐standing poly( para ‐phenylene) (PPP) films have been electrosynthesized by direct oxidation of benzene on stainless steel electrode in mixed e1ectrolytes of boron trifluoride diethy1 etherate (BFEE) and trifluoroacetic acid (TFA). The oxidation potential of the monomer in these media is lower than those…
Abstract Metallocene polyethylene (mPE) fractions are recognized as being more homogeneous with respect to short‐chain branch (SCB) distribution as compared with unfractionated mPEs. Differential scanning calorimetry and polarized optical microscopy (POM) were used to study the influences of SCB content on the crystal…
Abstract The bisphenol 4,4″‐dihydroxy‐5′‐phenyl‐ m ‐terphenyl ( 4 ), containing a 1,3,5‐triphenylbenzene moiety, was synthesized from a pyrylium salt obtained by the reaction of benzaldehyde with p ‐methoxyacetophenone with boron trifluoride etherate as a condensing agent. Polymers were obtained from 4 by a nucleophil…
The perovskite oxide ${\mathrm{Sr}}_{2/3}{\mathrm{La}}_{1/3}{\mathrm{FeO}}_{3}$ has been found to switch its electronic ground state drastically at 23 GPa through measurements of ${}^{57}\mathrm{Fe}$ M\"ossbauer spectroscopy and powder x-ray diffraction up to 56 GPa. In the low-pressure region a first-order transition…
We present a first-principles calculation of the theoretical shear strength of the Al\ensuremath{\Sigma}3(112\ifmmode\bar\else\textasciimacron\fi{}) tilt boundary. Here we replace the usual \ensuremath{\gamma} surface (defined by rigid atomic translations parallel to the boundary) by a ``generalized \ensuremath{\gamma…