Materials Literature
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Abstract The effect of the heat treatment on as‐spun fibers made of a commercial liquid crystalline polymer, Vectra®, was examined through tensile properties and differential scanning calorimetry (DSC) measurements. The heat treatment increased the fiber strength considerably, and it also increased the elongation at b…
Abstract Modification of fluorine‐containing polymers has recently received much attention due to new chemistries allowing for refunctionalization of these materials, especially their surfaces. In this article results are discussed which demonstrate various interesting modifications (including incorporations of OH an…
Abstract The phase behavior of a series of styrene/maleic anhydride (SMA) copolymers with various polyacrylate and polymethacrylate homopolymers has been investigated using various techniques. None of the polyacrylates are miscible with SMA copolymers. Poly (methyl methacrylate) (PMMA) poly(ethyl methacrylate) (PEMA)…
Abstract The permeability of isotactic poly(phenyl silsesquioxane) (PPSQ) to O 2 and N 2 at 25.0°C and to CO 2 and CH 4 at 35.0°C was measured at low pressures by the “time‐lag” method. PPSQ is a glassy silicone polymer with an 8‐atom ring structure of alternating Si and O atoms. The CO 2 /CH 4 selectivity of PPSQ is…
Abstract The ESR study of the radicals formed in mechanochemical polymerization of acrylamide (AAM) was undertaken. The nature of the radical formation was compared with the mechano‐radical formation produced by mechanical fracture of polyacrylamide (PAAM). The structure of radicals formed were all identified to be an…
Abstract Unsaturated polyanhydrides of the structure [(COCHCHCOO) x (CORCOO) y ] n , were synthesized. The polymers were prepared by either melt or solution polycondensation. Weight average molecular weights of up to 30,000 were obtained. The double bonds remain intact throughout the polymerization proce…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTHeterosilsesquioxanes: synthesis and characterization of Group 15 containing polyhedral oligosilsesquioxanesFrank J. Feher and Theodore A. BudzichowskiCite this: Organometallics 1991, 10, 3, 812–815Publication Date (Print):March 27, 1991Publication History Published online1…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTFerromagnetic behavior of linear-chain electron-transfer complexes. Synthesis and characterization of decaethylferrocene, Fe(C5Et5)2, and its electron-transfer salts: structure and magnetic properties of [Fe(C5Et5)2].bul.+[A].bul.- [A = TCNE and TCNQ]Kai Ming. Chi, Joseph C.…
Photoconductivity in the visible region has been studied in diamond films (DF) grown by the chemical vapor deposition process. It was found that the photocurrent increased linearly with the external bias voltage within the experimental range (30 V). Moreover, by exposing both boron-doped and undoped DF samples in air…
The authors first calculate a standard 'linear muffin-tin orbital' band structure (including combined correction and exchange correlation) for TiO 2 compounds in rutile structure. The outcoming bands, especially the last valence (mostly O 2p states) and first conduction (mostly Ti t 2g states) bands, are fairly hybrid…
We report a first observation of the remarkably low electrical resistivity of copper germanide thin films formed at temperatures below 200 °C. At these low temperatures, the ε-Cu3Ge phase with a monoclinic crystal structure is formed, with room-temperature resistivity which can be as low as 5.5 μΩ cm. The films are el…
This paper reports optical absorption and luminescence studies of Cr3+-doped silicate glasses with compositions chosen to vary the octahedral crystal-field splitting at the Cr3+ site. The extensive site-to-site disorder in the glasses is signalled by the inhomogeneous broadening of radiative transitions and by non-exp…
We measured third-order, nonlinear optical susceptibility χ(3) for a series of tetrabenzporphyrins in solution in tetrahydrofuran at 532 nm using degenerate four-wave mixing with picosecond pulses and obtained values of molecular second hyperpolarizability 〈γ〉. The corresponding macroscopic χ(3) values calculated for…
Abstract Styrene‐acrylic acid copolymers exhibit miscibility with various aliphatic, crystalline polyamides (e.g., nylon 6, 11, and 12) at 20% acrylic acid content in the copolymer. At 8% acrylic acid, phase separation is observed with the crystalline polyamides. At 14% acrylic acid, partial miscibility is observed wi…
Abstract Na + and Cl ‐ transport across 2.4‐ and 5.2‐μm‐thick polyimide (PI) PMDA/ODA and 7.5‐μm‐thick du Pont Kapton films was studied in a diffusion cell using ion‐selective electrodes. The temperature was 30°C. Diffusion coefficients D m (in cm 2 /s), permeability coefficients P (in cm 2 /s), and distribution coeff…
Abstract The gas transport properties of several simple vinyl and vinylidene polymers are compared to examine the effect of pendant group type (H, CH 3 , F, Cl) and symmetry of placement. The literature contains extensive information about these polymers, which has been critically reviewed to obtain consistent data fo…
Abstract A mathematical model of the melt spinning process that includes crystallization has been used to compute the velocity, diameter, temperature, and birefringence as a function of distance from the spinneret. An improved inversion procedure is described and is shown to give better results for the computed appare…
Abstract We measured thermal conductivities as well as electric conductivities of some composites in several types of dispersion systems. The dispersion state, that is, the ease in forming conductive chains in these composites, was estimated by the characteristic electric conductivities and compared with the thermal c…
The recovery of proteins following denaturation is optimal at low protein concentrations. The decrease in yield at high concentrations has been explained by the kinetic competition of folding and "wrong aggregation". In the present study, the renaturation-reoxidation of hen and turkey egg white lysozyme was used as a…
The Kapitza conductivity (thermal boundary conductivity (TBC)) between two crystals is studied within a simple three-dimensional lattice dynamical model and the role of interface roughness on an atomic scale is investigated. The interface roughness is modelled by a random alloy monolayer A 1-x B x between the two semi…