Serwis Infona wykorzystuje pliki cookies (ciasteczka). Są to wartości tekstowe, zapamiętywane przez przeglądarkę na urządzeniu użytkownika. Nasz serwis ma dostęp do tych wartości oraz wykorzystuje je do zapamiętania danych dotyczących użytkownika, takich jak np. ustawienia (typu widok ekranu, wybór języka interfejsu), zapamiętanie zalogowania. Korzystanie z serwisu Infona oznacza zgodę na zapis informacji i ich wykorzystanie dla celów korzytania z serwisu. Więcej informacji można znaleźć w Polityce prywatności oraz Regulaminie serwisu. Zamknięcie tego okienka potwierdza zapoznanie się z informacją o plikach cookies, akceptację polityki prywatności i regulaminu oraz sposobu wykorzystywania plików cookies w serwisie. Możesz zmienić ustawienia obsługi cookies w swojej przeglądarce.
Stochastic molecular descriptors have been applied in QSAR studies on small molecules and polymers (including our series in Polymer) [H. González-Díaz, A.R. Ramos de, R.R. Molina, Bioinformatics 19 (2003) 2079–2087; H. González-Díaz, R.R. Molina, E. Uriarte, Bioorg Med Chem Lett 14 (2004) 4691–4695; H. González-Díaz, R.R. Molina, E. Uriarte, Polymer (I) 45 (2004) 3845–3853; H. González-Díaz, E. Olazábal,...
Raman spectroscopy has been used as a tool to monitor the microdeformation of a range of process-controlled fibres with different orientations. The mechanical properties of the fibres are shown to be related to the orientation parameter (〈sin 2 θ〉), and that by using the particular fibre spinning process (N-methylmorpholine N-oxide (NMMO)/cellulose), a plateau is reached, beyond which no improvements...
The distribution of processing oil in two olefinic thermoplastic elastomer (OTPE) blends was determined using dielectric spectroscopy. The OPTE blends are blends of dynamically vulcanised EPDM with polypropylene (PP), TPVs, and blends of PP with SEBS. Both blend types contain paraffinic oil, which is present in both the PP and in the elastomer phase. The determination of the actual oil concentration...
A remarkable correlation exists between the degree of expansion of polyurethane foams and the structure of the reacting premixes. Polyurethane foams obtained from reacting premixes containing microemulsions are highly expanded. The expansion rate is proportional to the volume fraction of microemulsion in the premix. The stability of premixes with and without microemulsion is completely different suggesting...
The time development of the surface morphology of asymmetric polystyrene-b-poly(4-vinylpyridine) (PS-b-P4VP) thin films ‘annealing’ in methanol vapor, a selective solvent for minority P4VP block, was investigated by atomic force microscopy(AFM). For PS-b-P4VP with cylindrical structure in bulk, as annealing time progressed, the surface morphology underwent structural transitions from featureless topography...
Polymer–polymer blends of rigid-rod and random-coil macromolecules are obtained by ionomer blend formation. The molecular dispersion of the rod molecules in the matrix polymer is achieved by acid–base interactions. The reinforcement effect in terms of the Young's modulus is discussed as a function of the degree of polymerization of the rods. By treating the reinforcer molecule as a fuzzy cylinder...
An in situ and single-step route to creating a uniform dispersion of lanthanum(III) oxide nanoparticles in a polyimide is described. The process of thermally evolving, from the diaquotris(2,4-pentanedionato)lanthanum(III) complex, to a homogeneous dispersion of lanthanum(III) oxide nanoparticles within a 6FDA/1,3(3)-APB polyimide matrix has been characterized. The report also describes the resulting...
The molecular orientation and deformation mechanisms of a quenched isotactic polypropylene (iPP) film deformed at temperatures between 303K and the melting point are studied. At draw temperature T E less than 400K where the degree of crystallinity does not change markedly, a linear relationship between molecular orientations of the crystalline and the amorphous phases is revealed and the slope...
Polycarbonate/poly(ε-caprolatone), PC/PCL, amorphous miscible blends with 90/10 and 80/20 composition in weight, have been studied by X-ray diffraction and broad-band dielectric spectroscopy. The molecular dynamics for the high T g component segmental mobility have been followed by analyzing the isothermal dielectric losses as a function of frequency with Havriliak–Negami distributions. The...
The synthesis of hyperbranched poly(methyl methacrylate) (PMMA) via reversible addition fragmentation chain transfer (RAFT) polymerization was investigated by varying the ratio chain transfer agent (CTA): monomer (methyl methacrylate, MMA): brancher (ethylene glycol dimethyl methacrylate, EGDMA): free radical initiator (AIBN) at various temperatures (50, 55, 60, 65, 70°C). The rate of polymerization...
Typical polyHIPE (porous polymers from high internal phase emulsions) have a cellular structure with volume fractions from 0.2 to 0.04, cell diameters from 15 to 25μm and intercellular pore diameters from 0.5 to 10μm. Unique interpenetrating polymer networks synthesized within the polyHIPE exhibited enhanced mechanical properties and an extended temperature range for damping. Hybrid polyHIPE that...
The excited states of the fluorene–thiophene compounds whose polymers are useful as a light-emitting diode were studied by SAC–CI method. The effect of the torsional angle on the excited state was examined for the FT and FMT monomers in details. The first three excited states were calculated for the conformers of several torsional angles. These three excited states were found to change their characters...
A study of the reinforcement effect of a soft polymer matrix by hard nanometric filler particles is presented. In the main part of this article, the structure of the silica filler in the matrix is studied by small angle neutron scattering (SANS), and stress–strain isotherms are measured to characterize the rheological properties of the composites. Our analysis allows us to quantify the degree of aggregation...
The permeabilities of He, H 2 , N 2 , O 2 , CO 2 , CH 4 , C 2 H 6 , C 3 H 8 , and n-C 4 H 10 in poly[1-phenyl-2-[p-(trimethylsilyl)phenyl]acetylene] (PTMSDPA) and poly[diphenylacetylene] (PDPA) are presented and compared to those of poly(1-trimethylsilyl-1-propyne) (PTMSP), poly(1-phenyl-1-propyne) (PPP), and polysulfone...
The immobilization of octamethyl-14-crown-4 onto crosslinked polymer supports is reported and the selectivity for Li(I) from aqueous solutions quantified. The amount of Li(I) complexed by the crown ether is affected by the polarity of the polymer matrix: Complexation increases with increasing matrix hydrophilicity. Poly(glycidyl methacrylate) is the preferred support matrix for the crown ether.
High-temperature composites were successfully prepared from aminated polysulfone, polyphenylsulfone, and a rod-like polymer polybenzimidazole (PBI). The single glass transition temperature T g and the absence of evidence for phase separation in scanning electron microscopy suggested that these systems formed so-called ‘molecular composites’. The enhanced miscibility between the polymer pairs...
The mechanical properties of nylon-6/clay nanocomposites with variations in clay aspect ratio and orientation were studied. A large-scale simple shear process was utilized to alter the clay aspect ratio and orientation within the reference nanocomposite. It was found that the modulus, strength, and heat distortion temperature of the nanocomposites decreased as the clay aspect ratio and degree of orientation...
It has been shown in a previous paper in this series that important dilatation is produced by plastic deformation under tension of neat PP and PP/PA6/POE blends, for which the POE to PA6 concentration ratio equals 1/2. In this work, the detailed mechanisms of this volume change are investigated from electron micrographs (SEM and TEM) obtained in the deformed state. At low alloy content, it is thus...
The adsorption of several types of conducting polymers on carbon nanotubes is investigated by electrical transport measurements. We report the optoelectronic properties occurring in single-walled carbon nanotubes (SWNTs) conjugated polymer, poly(3-octylthiophene), composites. Al/polymer-nanotube composite/indium–tin oxide diodes show photovoltaic behavior proposing that the main reason for this increase...
Thermomechanical properties of polymer blends seem to depend on their morphology on microscales and in particular on the size of the dispersed phase particles and/or their distances (ligament thickness). Precise characterization of morphologies by few simple geometrical parameters is often a quite delicate task, in particular because of the strong polydispersity of these systems. We present here a...
Podaj zakres dat dla filtrowania wyświetlonych wyników. Możesz podać datę początkową, końcową lub obie daty. Daty możesz wpisać ręcznie lub wybrać za pomocą kalendarza.