Materials Literature
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SIR 97 is the integration of two programs, SIR 92 and CAOS , the first devoted to the solution of crystal structures by direct methods, the second to refinement via least-squares–Fourier procedures. Several new features have been introduced in SIR 97 with respect to the previous version, SIR 92: greater automatization…
Stress oscillations were produced and analyzed in partly-crystalline syndiotactic polypropylene (sPP) and in poly(ethyleneterephthalate) (PET) in cold drawing experiments. Strain oscillations, which always occur in connection with stress oscillations, were also investigated. The experiments were performed varying the…
Living polytetrahydrofuran (pTHF) was terminated with the potassium salt of pyrrole to yield polymers with pyrrole end groups. Copolymerization of THF and pyrrole with short and long pTHF segments was achieved by constant potential electrolysis. Syntheses of the block copolymers were performed using tetrabutylammonium…
Jute yarns soaked for 30 min in 2-hydroxyethylmethacrylate (HEMA) + MeOH solutions at different proportions [1–20% HEMA in MeOH (v/v)] were irradiated in situ with a UV lamp for different periods. The treated jute yarns that were washed in acetone after the irradiation to remove the unused excess monomer HEMA gained a…
This article reports the toughness improvement of high-density polyethylene (HDPE) by low-density polyethylene (LDPE) in oscillating packing injection molding, whereas tensile strength and modulus are greatly enhanced by oscillating packing at the same time. Compared with self-reinforced pure HDPE, the tensile strengt…
The incorporation of 2.2 mol % sodium sulfonate groups along the backbone of syndiotactic polystyrene dramatically inhibits crystallization from the melt. However, small amounts of a surfactant, such as sodium dodecylbenzenesulfonate (DBSNa), may be used to selectively plasticize the ionic domains of sulfonated polyst…
ADVERTISEMENT RETURN TO ISSUEPREVCommunication to the...Communication to the EditorNEXTAnalysis of an Interface between an Immiscible Polymer Pair by Electron Spectroscopic ImagingShin Horiuchi, Takeshi Hanada, Kiyoshi Yase, and Toshiaki OugizawaView Author Information National Institute of Materials and Chemical Rese…
Phase separation in polymers is important for many technical applications but is difficult to predict theoretically. Recently, extensive experimental studies on the miscibility of polyolefins revealed that these systems display a wider variety of mixing behavior than their chemical similarity suggests. In order to pre…
Dendrimers, the most highly branched structures achievable, have found numerous uses in the chemical, biological, and pharmaceutical fields. We have employed size exclusion chromatography (SEC) with universal calibration to determine molecular weight averages, distributions, intrinsic viscosities, and structural param…
We report the synthesis and 1 H, 13 C{ 1 H}, and phase-sensitive HETCOR NMR spectra of atactic poly(lactide), poly( meso -lactide) and poly( rac -lactide). The new and existing spectroscopic data are discussed in terms of four alternative explanations: (i) Kricheldorf's tetrad assignments with the presumption that the…
We studied changes in magnesium oxide upon rehydration under operating conditions similar to those used in the subsequent impregnation of a metal salt on its surface. The ensuing transformations were monitored by using the XRD, TPR, and 1 H MAS NMR techniques. On the basis of the results, magnesium oxide (periclase ph…
ADVERTISEMENT RETURN TO ISSUEPREVCommunication to the...Communication to the EditorNEXTVersatile Synthesis of Polysaccharide Hydrogels Using the Passerini and Ugi Multicomponent CondensationsArjan E. J. de Nooy, Giancarlo Masci, and Vittorio CrescenziView Author Information Department of Chemistry, University 'La Sapi…
The photophysical properties of a multicomponent array consisting of a free-base aryl-porphyrin and a gold(III) aryl-porphyrin, assembled via a central bis(terpyridine) ruthenium(II) complex, PH 2 −Ru−PAu, have been studied in low-temperature glassy media by steady state and time-resolved methods. Comparison of the ph…
A finite element implementation is reported of the Fleck–Hutchinson phenomenological strain gradient theory. This theory fits within the Toupin–Mindlin framework and deals with first-order strain gradients and the associated work-conjugate higher-order stresses. In conventional displacement-based approaches, the inter…
The exact physical and chemical nature of 55 million gallons of radioactive toxic waste held in 177 underground waste tanks at the Hanford Site is not known with sufficient detail to support the safety, retrieval, and immobilization missions presented to Hanford. The purpose of this study is to estimate probability di…
Experimental solubilities are reported for anthracene dissolved in ternary 2-butoxyethanol + cyclohexane + 1-propanol, 2-butoxyethanol + cyclohexane + 2-propanol, 2-butoxyethanol + heptane + 1-propanol, and 2-butoxyethanol + heptane + 2-propanol solvent mixtures at 298.15 K. Nineteen compositions were studied for each…
Reactions with semiconductor surfaces are important for many processes such as epitaxial growth, dopant incorporation, and patterning that underlie semiconductor technology. Recent advances in scanning tunneling microscopy techniques have enabled substantial progress in identifying the underlying processes. The studie…
The phase separation of a thin polymer blend layer undergoing a simultaneous transesterification reaction is examined by a variety of experimental techniques [neutron and X-ray reflectivity, optical microscopy, atomic force microscopy (AFM)] to determine morphological features unique to reactive phase separation. Neut…
Results of investigations of the gas-phase reactions of nickel and nickel oxide ions with NO 2 are reported in this final part of a four-part series. A fast flow reactor−quadrupole mass spectrometer system coupled with a laser vaporization source is used to study reactions of nickel and nickel oxide cluster ions with…
ADVERTISEMENT RETURN TO ISSUEPREVNoteNEXTAn Electrosynthetic Path toward PentaporphyrinsLaurent Ruhlmann, Sylvie Lobstein, Maurice Gross, and Alain GiraudeauView Author Information Laboratoire d'Electrochimie et de Chimie Physique du Corps Solide, U.M.R. No. 7512, CNRS, Université Louis Pasteur, 4 rue Blaise Pascal, F…