Materials Literature
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New polyarylates having benzopinacolone units were synthesized from 2,2-bis(4-hydroxyphenyl)-1,2-diphenylethanone and aromatic dicarboxylic acid chlorides. The polymers having an inherent viscosity of 0.71–0.94 dL/g were obtained by the two-phase method using toluene as an organic solvent. The polymers were easily sol…
We studied the photolysis of a fluoroethylene–fluoropropylene copolymer (FEP) film by vacuum ultraviolet (VUV) radiation from a resonance Xe lamp at a wavelength of 147 nm and air pressures of 0.05 and 2.5 Torr. The chemical changes in the FEP surface layer were investigated by Fourier-transform infrared spectroscopy…
The mechanism of thermal degradation of homopolymers of styrene (St) and methacrylonitrile (MAN) and their copolymers was investigated theoretically and experimentally by the pyrolysis gas chromatography using a Curie-point pyrolyzer. Poly(St-co-MAN)s generate dimers and trimers as well as monomers by flash pyrolysis.…
A two-dimensional conducting polyaniline (PAN) monolayer has been formed on an electrically insulating monolayer. The approach is based on the electrochemical polymerization of surface-confined anilinium ions that were electrostatically attached to a negatively charged self-assembled monolayer of ω-mercaptodecanesulfo…
The conditions for the crystallization of form II of syndiotactic polypropylene are described. As-prepared, melt-crystallized, and oriented-fiber specimens of different samples of syndiotactic polypropylene having different degrees of stereoregularity, prepared with a metallocene-based catalyst as well as with the tra…
Thermoplastic elastomer gels (TPEGs) composed of a poly[styrene-b-(ethylene-co-butylene)-b-styrene] triblock copolymer and a low-volatility, midblock-compatible mineral oil have been investigated at different oil concentrations to ascertain the effect of composition on TPEG morphology and mechanical properties. The im…
A positive-working photosensitive polyimide precursor based on fluorinated poly(amic acid) (FPAA) and 2,3,4-tris(1-oxo-2-diazonaphthoquinon-4-ylsulfonyloxy)benzophenone (D4SB) as a photosensitive compound has been developed. FPAA was prepared by ring-opening polyaddition of dianhydrides, pyromellitic dianhydride and b…
In the search for new packaging materials for the electrical/electronics industry, three types of polymer composites have been studied. Silicone/boron nitride powders, polyurethane/alumina powders, and polyurethane/carbon fibers have all been synthesized to study the moisture–absorption kinetics, thermal conductivitie…
This paper investigates sulfur poisoning and catalyst regeneration for alumina-supported platinum, palladium, and rhodium catalysts. Reduced catalysts and regenerated sulfur-poisoned catalysts were studied for their activity in the catalytic combustion of methane in a flow microreactor. CO adsorption, in conjunction w…
Adsorption of poly( tert -butylstyrene)/poly(styrenesulfonate) diblocks on polystyrene latices from water is reported and interpreted with scaling theories to demonstrate the effects of ionic strength and curvature on layer thickness. The adsorbed amount increases with ionic strength from no added salt to 0.1 M, formi…
A new adamantane-based dietheramine, 2,2-bis[4-(4-aminophenoxy)phenyl]adamantane, was prepared in two steps from chloro displacement of p -chloronitrobenzene with the potassium phenolate of 2,2-bis(4-hydroxyphenyl)adamantane, followed by hydrazine catalytic reduction of the intermediate dinitro compound. A series of p…
Using molecular dynamics simulations, with a realistic many-body embedded-atom potential, and a novel method to characterize local order, we study the structure of pure nickel during the rapid quench of the liquid and in the resulting glass. In contrast with previous simulations with pair potentials, we find more crys…
Organosilicon carbodiimides have been successfully applied as single-source precursor compounds for the synthesis of novel ternary Si-, C-, and N-containing solid phases. Their thermally induced decomposition gives either amorphous silicon carbonitrides or polycrystalline silicon nitride and silicon carbide mixtures,…
The free-carrier screening of macroscopic polarization fields in wurtzite GaN/InGaN quantum wells lasers is investigated via a self-consistent tight-binding approach. We show that the high carrier concentrations found experimentally in nitride laser structures effectively screen the built-in spontaneous and piezoelect…
The theory of nematic-smectic phase transition in the system of uniform semi-flexible chains with hard-core repulsion is presented. Both the general density-functional formalism the tube-model calculation show that the flexibility of the chains results in a strong first-order transition, in contrast to the common weak…
We present simulations of metallization morphologies under ionized sputter deposition conditions, obtained by a new theoretical approach. By means of molecular dynamics simulations using a carefully designed interaction potential, we analyze the surface adsorption, reflection, and etching reactions taking place during…
One approximation is made to describe a M+1 electron many-body wavefunction by a M electron many-body wavefunction and a single electron wavefunction. Under this approximation, we have derived the Coulomb energy which relates the exciton energy $E_{exc}$ in a quantum dot with the quasiparticle band gap (defined as the…
Borophosphates (intermediate compounds of the system M x O y −B 2 O 3 −P 2 O 5 −(H 2 O)) contain complex anionic structures built of BO 4, BO 3, and PO 4 groups and their partially protonated species, respectively. A first approach to the development of a structural chemistry of borophosphates is based on linking prin…
The incorporation of the five following porphyrins: meso-tetra(4-phenyl)porphyrin (TPP); meso-tetra(4-sulfonato-phenyl)porphyrin (TPPS4); meso-tetra(4-naphthyl)porphyrin (TNP); tri-sulfo-tetra-phenyl porphyrin (TPPS3) and tetra-sulfonato-naphthyl porphyrin (TNPS4) into human blood cells was investigated using flow cyt…
The multichannel CH + NO reaction was studied, at room temperature, in a low-pressure fast-flow reactor. CH was obtained from the reaction of CHBr 3 with potassium atoms. The overall rate constant was found to be (1.9 ± 0.5) × 10 -10 cm 3 molecule -1 s -1 . The relative branching ratios of NH(A 3 Π) + CO and NCO(A 2 Σ…