Materials Literature
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Improvement of processability of Poly(ε-caprolactone) (PCL) was achieved by introduction of a branch structure using gamma-irradiation from a 60Co source. Irradiated PCL has higher molecular weight by producting a branch structure. Hence, the irradiation at a lower dose, such as 3 Mrad, leads to a higher melt viscosit…
Through differential scanning calorimetry, isothermal crystallization from the melt of polytetrafluoroethylene (PTFE) has been investigated. PTFE was regarded as one of the polymers for which crystallization is so rapid that the samples crystallize during the cooling from the melt to the selected crystallization tempe…
Crystallization and melting behaviors of poly(p-phenylene sulfide) (PPS) in blends with poly(ether sulfone) (PES) prepared by melt-mixing were investigated by differential scanning calorimetry (DSC). The blends showed two glass transition temperatures corresponding to PPS- and PES-rich phases, which increased with inc…
In this article, we describe the synthesis of polypeptides onto the whole specific surface of poly(ethylene terephthalate) particle track membranes. In this case, initial functionalization is necessary. It had been done by an optimized surface oxidation in accordance with the method of Marchant-Brynaert, J.; Deldime,…
Effects of corona treatment and aging on commercially produced corona discharged polypropylene (PP) films were followed via surface sensitive roughness analysis by atomic force microscopy (AFM), water contact angle (WCA), and X-ray photoelectron spectroscopic (XPS) measurements. Roughness analysis by AFM gave similar…
The physical aging of bisphenol A polycarbonate was studied using the differential scanning calorimetry technique. Cowie and Ferguson's model and Williams-Watts function were used to analyze the data. It is confirmed that the relation ΔH∞(Ta) = ΔCp(Tg − Ta), where ΔH∞(Ta) is the value of the aging enthalpy for t = ∞,…
We explore a new class of computationally feasible approximations of the two-body density matrix as a finite sum of tensor products of single-particle operators. Physical symmetries then uniquely determine the two-body matrix in terms of the one-body matrix. Representing dynamical correlation alone as a single tensor…
Interparticle interaction and structure of glycogen from a shell fish (mussels) were studied in water and 0.5 N NaOH by static and dynamic light scattering and viscometry. A concentration regime up to 30% w/v was covered. Beyond the overlap concentration a large-scale clustering was observed which was interpreted as a…
The [P 2 W 18 M 6 S 6 O 74 (H 2 O) 6 ] 12 - anions, M = Mo, W, were obtained through the stereospecific addition of the dithiocation [M 2 O 2 S 2 ] 2+ to the trivacant A-α-[PW 9 O 34 ] 9 - . K 12 [P 2 W 18 Mo 6 S 6 O 74 (H 2 O) 6 ]·26H 2 O has been isolated as crystals and has been characterized by X-ray diffraction (…
In this paper we describe an experimental procedure that can be used to study the photoreduction of metal ions on the surfaces of individual TiO 2 particles. The submicrometer-sized particles are isolated on porous membranes, characterized by atomic force microscopy (AFM), removed from the microscope, exposed to AgNO…
An azocarbazole-based polyimide was synthesized from an azocarbazole diamine monomer and 4,4‘-(hexafluoroisopropylidene)diphthalic anhydride (6FDA) by a two-step polycondensation reaction. Birefringence experiments have been performed on the pure polyimide and on the polyimide mixed with small azo chromophores. Becaus…
A chemically prepared emeraldine chloride powder has been studied by high-resolution electron microscopy. Two kinds of grains with varying degrees of crystallinity were observed: (i) Rolled sheets (20−100 nm in diameter) (aggregates, disks, or ribbons?) with an amorphous surface layer are identified as the EB-II polym…
The acid-catalyzed condensation of 4-hydroxyphenylmethyl ketone (p-hydroxyacetophenone) with pyrrole affords a new type of calix[4]pyrrole derivative that contains deep cavities and fixed walls. These new systems, which can be readily converted into the corresponding 4-methoxyphenyl species, can exist in the form of f…
Catalytically grown graphite nanofibers (GNF) are molecularly engineered structures that are produced by the interaction of carbon-containing gases with small metal particles at temperatures around 600 °C. The fibrous solids consist of minuscule graphene sheets stacked at various angles with respect to the fiber axis.…
We calculate the value of the Fröhlich electron-phonon interaction in manganites, cuprates, and some other charge-transfer insulators and show that this interaction is much stronger than any relevant magnetic interaction. A polaron shift due to the Fröhlich interaction, which is about 1 eV, suggests that carriers in t…
This is a short review of the physical ideas,algorithm for the calculation of the phase transition pressure and some results of a semi-classical theory of the behaviour of materials under high pressure proposed by P.Savic and R.Kasanin.It is base on the Coulomb interaction,supplemented by a microscopic selection rule…
A mechanism of the parity effect in the thermally assisted resonant tunneling is proposed in the view point of nonadiabatic transitions of thermally excited states. In this mechanism, alternating enhancement of the relaxation is naturally understood as a general property of quantum relaxation of uniaxial magnets at fi…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTNiobium Compounds: Preparation, Characterization, and Application in Heterogeneous CatalysisIzabela Nowak and Maria ZiolekView Author Information A. Mickiewicz University, Faculty of Chemistry, Grunwaldzka 6, 60-780 Poznan, Poland Cite this: Chem. Rev. 1999, 99, 12, 3603–362…
Brewster angle microscopy, interfacial stress rheometry, and Π− A isotherm measurements are employed to characterize spread monolayers of two new cellulose derivatives, one containing octadecyl side chains, the other p -nitroaniline substituents. Similar monolayer phase behavior is found in both cases. At high surface…
The electronic and geometrical structures of the ground states and low-lying isomers of MnO 4 and MnO 4 - have been calculated as a function of spin-multiplicities by using the molecular orbital theory based on generalized gradient approximation to the density functional formalism. Total energies of isomers are used f…