Materials Literature
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The relationship between elastic strain gradient and electric polarization was investigated in the relaxor ferroelectric lead magnesium niobate ceramic. Experimental studies indicated that flexoelectric polarization is linearly proportional to the applied strain gradient, and the flexoelectric coefficient μ12 is calcu…
For the ferroelectric perovskite compounds ${\mathrm{BaTiO}}_{3}$ and ${\mathrm{PbTiO}}_{3},$ we have studied the effects of external electric fields on the structural properties of the (001) surfaces. The field-induced changes in the surface interlayer spacings and bucklings have been calculated using a first-princip…
The miscibility and phase behavior in blends of poly(vinyl butyral) (PVB) and atactic poly(methyl methacrylate) (PMMA) were studied by dynamical mechanical thermal analysis (DMTA) and optical microscopy (OM). PVB is regarded as a random copolymer containing vinyl butyral (VB) and vinyl alcohol (VA) units. In this stud…
Intermolecular contacts in crystals of monoclinic form hen egg-white lysozyme were analyzed using the macrobond approach. Both the macroscopic crystal morphology and the microscopic morphology observed by atomic force microscopy were explained well using macrobond energies. The features of the advancing steps of the g…
This study introduces the phase diagram and interfacial characteristics of a novel lyotropic polymeric liquid crystal. The polymer consists of an α-methylstilbene mesogenic group bridged by a low interfacial energy perfluorocyclobutyl ring via flexible aryl ether linkages. The polymer, obtained by thermal cyclopolymer…
We have previously shown that infrared spectroscopy can be used to “count” the number of contacts in hydrogen-bonded system. We use such information to determine appropriate self- and interassociation equilibrium constant values and at the same time take into account the intramolecular “screening” in polymer blends an…
Static and dynamic scattering properties of (a−b) diblock copolymer chains having different architectures are discussed in the framework of the random phase approximation (RPA). The case of a symmetric diblock (50/50) in a solvent satisfying the zero average contrast condition, in the semidilute regime, is considered…
ADVERTISEMENT RETURN TO ISSUEPREVNoteHigh Molecular Weight Aromatic Polyformals Free of Macrocyclic Oligomers. A Condensative Chain Polymerization ReactionKenji Miyatake, Antisar R. Hlil, and Allan S. HayView Author Information Department of Chemistry, McGill University, 801 Sherbrooke St. W., Montreal, Quebec H3A 2K6…
We have found, when inherently immiscible polymers are included as guests in the narrow channels of their common inclusion compounds (ICs) formed with host cyclodextrins (CDs) and then these polymer-1/polymer-2-CD-IC crystals are washed with hot water to remove the host CD lattice and coalesce the guest polymers, that…
Sialic acid dendrons bearing a focal aldehyde end group were synthesized by a reiterative amide bond strategy. Polyamine-ending trivalent ( G = 1) and nonavalent ( G = 2) dendrons having gallic acid as branching unit and tri(ethylene glycol) as spacer arm were prepared and initially attached to a sialic acid p- phenyl…
Blends of poly(vinylphenol- co -methyl methacrylate) (PVPh- co -PMMA) with poly(ethylene oxide) (PEO) were prepared by solution casting from tetrahydrofuran (THF) solution. The miscibility behavior and hydrogen bonding of blends were investigated by differential scanning calorimetry (DSC), Fourier transform infrared s…
ADVERTISEMENT RETURN TO ISSUEPREVCommunication to the...Communication to the EditorNEXTNMR Measurements Related to Clay-Dispersion Quality and Organic-Modifier Stability in Nylon-6/Clay NanocompositesD. L. VanderHart, A. Asano, and J. W. GilmanView Author Information Polymers Division, Mailstop 8544, National Institut…
Craze formation determines the effective strength of many structural polymers and glassy polymer adhesives. We use molecular dynamics simulations to study the evolution of craze formation in glassy polymers as the number of monomers per chain N increases. When N is less than the entanglement length N e, the polymer ca…
This article discusses advances in understanding the structural and physicochemical characteristics of suspensions of cellulose crystallites prepared by acid hydrolysis of natural cellulose fibres. Consideration of recent developments in visualization of crystallite ultrastructure may provide clues to suspension behav…
A scheme to evaluate the Griffith work of interfacial separation, 2γ int , is proposed based on first principles to investigate the segregation effects on a Σ11[1 0]/(11 ) γ-iron grain boundary. The chemical interaction of substitutional segregants Cr and Mn is able to enhance the cohesion of the grain boundary by ani…
The melting temperature of nano-ice confined in micropores of MCM-41 is predicted by use of our simple model based on the Lindemann criterion. The model takes into consideration the density of the OH bonds of MCM-41 pores; its prediction is consistent with the experimental results for the melting temperature of nano-i…
Study of the relaxation behaviour of a tri-epoxy compound in the supercooled and glassy state by broadband dielectric spectroscopy, D Pisignano, S Capaccioli, R Casalini, M Lucchesi, P A Rolla, A Justl, E Rössler
Aus vielen kristallinen Festkörpern lassen sich keine hinreichend großen und/oder für die Untersuchung mit Einkristall-Röntgenbeugungsverfahren qualitativ geeigneten Einkristalle erhalten. Darum ist für das Verständnis der strukturellen Eigenschaften solcher Stoffe die Möglichkeit zur Strukturbestimmung aus Pulverbeug…
Low-frequency dielectric measurements are performed on a nonchiral liquid crystal (8CB) for two different cell thicknesses 4.5 µm and 1.6 µm, as functions of temperature at various amplitudes of the probe field. Relaxation peak frequencies are observed at ~10 Hz for the 4.5 µm thick sample and ~100 Hz for the 1.6 µm c…
Gefahrlose und hochselektive H2O2-Produktion gelingt mit einem Membranreaktor mit folgendem Aufbau: Eine H2-permselektive Membran (2), bestehend aus dünnen Filmen einer Pd/Ag-Legierung (2b) und oxidiertem Pd (2c) sowie einer hydrophoben Polymermembran (2d), befindet sich auf einer röhrenförmigen Membran (2a) an der In…