Materials Literature
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Monoclinic (α) and hexagonal (β) polypropylene (α- and β-PP) were stained in the vapor of a ruthenium tetroxide solution prepared in situ. The effect of staining on the fusion behavior was investigated using a DSC. A staining duration between 10 and 24 h was found suitable for obtaining a good electron contrast betwee…
The disposal of used car tires has become a major environmental problem, especially in densely populated countries that use motor vehicles as the principle means of transportation. Widespread recycling of waste tires has not taken place because it has not proven to be cost effective. Although there are obvious environ…
The specific heats of rubber compounds are very important not only for the thermodynamic calculations in various rubber processings; mixing, extrusion, calendering, and vulcanization, etc., but also for the service life of the final products under repeated stressing conditions. In this study, the specific heats of var…
SWy-2 (Wyoming), STx-1 (Texas), and SAz-1 (Cheto, Arizona) montmorillonite and Sap-Ca saponite (California) were treated with different amounts of 12 M HCl and 1 M tetramethylammonium (TMA + ) chloride solution at room temperature. The catalytic activity of these hybrid acid-activated organoclays (AAOCs) was directly…
We have used albumin-modified atomic force microscope (AFM) tips to probe interactions with a range of hydrophilic polymer brush surfaces and protein. Copolymers of poly(ethylene oxide)−poly(propylene oxide)−poly(ethylene oxide) (PEO−PPO−PEO) (Pluronics) adsorbed onto polymer interfaces have been shown in previous stu…
Several methods for the synthesis of metal-free phthalocyanine (Pc or PcH 2 ) and copper phthalocyanine (PcCu) from urea and phthalic anhydride, phthalimide, 1,3-diiminoisoindoline (1,3-D), and phthalonitrile have been studied. The results show that the nature of the solvent is the most important factor in the convent…
As pointed out recently for the sulfoxidation of thioethers, 9 the most interesting aspect of oxidations with in situ generated unstable peroxynitrous acid is the short reaction time.Short reaction times may well be a crucial factor in the case of sulfur compounds of pharmaceutical and biological interest, which are n…
Single-crystal or very compact AgCl materials are hardly light sensitive. In presence of adsorbed Ag + ions, AgCl precipitates with their correspondingly large surface area, however, lead to the discovery of photography on paper by Henry Fox Talbot in 1834 and were recently found to act as a catalyst for sustained pho…
The design, synthesis, and characterization of amino acid-based cyclic bisureas, a new class of macrocyclic peptides, are described. These cystine-based macrocycles are constructed by a single-step procedure involving condensation of 1,ω-alkane diisocyanate[(CH 2 ) n (NCO) 2; n = 4, 6, 12] with either the simple l -cy…
We investigated the synthesis of nanometer scale homogeneous polystyrene and silica gel polymer hybrids utilizing ionic interactions. The partially sulfonated polystyrene (10 mol %) was used as a starting organic polymer and (3-aminopropyl)trimethoxysilane (APTMOS) was used as a countercation as well as the precursor…
ADVERTISEMENT RETURN TO ISSUEPREVCommunicationNEXTVery High-Spin Organic Polymer: π-Conjugated Hydrocarbon Network with Average Spin of S ≥ 40Andrzej Rajca, Suchada Rajca, and Jirawat WongsriratanakulView Author Information Department of Chemistry University of Nebraska Lincoln, Nebraska 68588-0304 Cite this: J. Am. C…
ADVERTISEMENT RETURN TO ISSUEPREVCommunication to the...Communication to the EditorOne-Dimensionally Periodic Dielectric Reflectors from Self-Assembled Block Copolymer−Homopolymer BlendsAugustine Urbas, Yoel Fink, and Edwin L. ThomasView Author Information Department of Materials Science and Engineering, M.I.T., Cambr…
We report the synthesis of six new dendrimers built around a [Ru(bpy) 3 ] 2+ -type core (bpy = 2,2‘-bipyridine) and bearing up to 24 4‘- tert -butylphenyloxy or 48 benzyl units in the periphery. The metallodendrimers were obtained by complexation of ruthenium trichloride or Ru(bpy) 2 Cl 2 with bipyridine ligands carry…
We simulate the phase separation of binary mixtures under shear in the presence of solid, mobile particles. We combine cell dynamical equations for the binary mixture with Langevin dynamics for the particles and carry out the simulations in two dimensions. One of the components preferentially wets the surface of the p…
Partially ordered micrometer-sized carbon tubes several centimeters in length have been prepared via a new chemical approach by the pyrolysis of composite fibers consisting of a thermally more stable polypyrrole (PPy) skin layer and a poly(ethylene terephthalate) core. The wall thickness of resultant hollow carbon tub…
Three- and four-arm poly(ethylene oxide) (PEOs) fractions have been synthesized to investigate the molecular shape dependence on polymer crystallization, melting, and annealing behaviors. Each arm in these star PEOs has a molecular weight (MW) of 2220 ( M a = 2220) and has been coupled using 1,3,5-benzene tricarbonyl…
ADVERTISEMENT RETURN TO ISSUEPREVCommunication to the...Communication to the EditorNEXTScreening of Optically Active Nickel Initiators for Enantioasymmetric Polymerization of γ-Benzyl Glutamate-N-CarboxyanhydrideJianjun Cheng and Timothy J. DemingView Author Information Departments of Materials and Chemistry, Universi…
The ambient temperature adsorption of acetonitrile (in its d 3 deuterated form, to avoid Fermi resonance band splitting in the analytical ν CN spectral region) was studied on pure γ-alumina, γ-alumina doped with two different amounts of sulfates, γ-alumina doped with Ca, and a Ca-doped alumina that was thermally trans…
Magnetic domain structure on the surface of the layer-structured ferromagnet La1.4Sr1.6Mn2O7 was observed in the temperature range from 37 to 97 kelvin with a scanning Hall probe microscope. The sensitivity to temperature of the domain structure changes was large relative to that in conventional ferromagnets. The stab…
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