Materials Literature
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The molecular structure of a series of hyperbranched polyesteramides was studied using size exclusion chromatography (SEC), mass spectrometry (MS) and small-angle neutron scattering (SANS). Products with increasing molecular mass were obtained through the polycondensation of in situ produced AB 2 -like monomeric units…
Abstract Recently, as a result of developments in nanotechniques, there has been a growing interest in the field of nanocomposites. The use of inorganic nanoparticle‐filled composites can provide high‐performance materials that find applications in several industrial fields. In the present work, preliminary studies co…
PhSb(dmit) (dmit(2)(-), 4,5-dithiolato-1,3-dithiole-2-thione), the first neutral organo-antimony dithiolene complex, has been synthesized by addition of PhSbCl(2) on a suspension of Na(2)(dmit). The complex was characterized by spectroscopic ((1)H and (13)C NMR and IR) methods and elemental analysis. Its crystal struc…
Abstract Montmorillonite minerals were modified in two distinct steps in order to remove hydroxlated toxicants from the aqueous environment. At first, the montmorillonite minerals were acrylated with the silylating agent γ‐methcaryloxypropyl trimethoxysilane to give a product denoted as TAY‐10. In the second step thes…
In connection with our chemotaxonomic studies of Malaysian species of the red algal genus Laurencia, the chemical composition of Laurencia pannosa Zanardini was examined. Two halogenated sesquiterpenoids, named pannosanol (1) and pannosane (2), have been isolated along with a halogenated C15-acetogenin, (3Z)-chlorofuc…
We report the results of resistivity (ρ), magnetoresistance (MR) and in-field heat capacity ( C ) measurements on TmCu and TmAg compounds. Despite the different nature of magnetic transitions - first-order in TmCu and second-order in TmAg - the magnetocaloric effect (MCE) obtained from in-field heat capacity data is s…
The syntheses, crystal and electronic structures, and linear optical properties of the new orthoborates LiMBO 3 (M = Sr, Ba) are reported here. These compounds, which crystallize in the monoclinic space group P 2 1 / n with cell dimensions a = 6.476(2), b = 6.684(3), c = 6.843(3) Å, β = 109.41(3)°, and Z = 4 for M = S…
Two new bis(ether anhydride)s, 2,2‘-dimethyl-4,4‘-bis[4-(3,4-dicarboxyphenoxy)]biphenyl dianhydride ( 4A ) and bis[4-(3,4-dicarboxy phenoxy)phenyl]diphenylmethane dianhydride ( 4B ), were prepared in three steps starting from nitrodisplacement of 4-nitrophthalonitrile with 2,2‘-dimethylbiphenyl-4,4‘-diol and bis(4-hyd…
A novel biphenylneolignan, 2,6,2',6'-tetramethoxy-4,4'-bis(2,3-epoxy-1-hydroxypropyl)biphenyl (1), and two new glycosides named atratoglaucosides A (2) and B (3), were isolated from the roots of Cynanchum atratum, and their structures were determined on the basis of chemical and spectroscopic evidence. The aglycons of…
Abstract Thermal decomposition kinetics of diglycidyl ether of bisphenol A (DGEBA)/4,4′‐methylene dianiline (MDA) system with rubber‐modified MDA was studied by the methods of Ozawa, Kissinger, and Friedman, and the kinetic parameters were compared. The thermal decomposition data of the cured epoxy resin were analyzed…
Abstract A new isomer of the oxozirconium cluster Zr 4 O 2 (methacrylate) 12 was obtained by reaction of zirconium butoxide with an excess of methacrylic acid. Contrary to the known isomer, the structure is centrosymmetric with a planar, rhombic Zr 4 core. Copolymerization with a 56–207‐fold excess of methylmethacryla…
Abstract The grafting of the methyl methacrylate (MMA) monomer onto natural rubber using potassium persulfate as an initiator was carried out by emulsion polymerization. The rubber macroradicals reacted with MMA to form graft copolymers. The morphology of grafted natural rubber (GNR) was determined by transmission ele…
Abstract A diol‐based refined, bleached, and deodorized (RBD) palm kernel oil polyol was prepared. It was found that the polyurethane foam produced only gives a good compressive strength property at a 45 kg/m 3 molded density. The combination of sorbitol into the polyol system resulted in a better dimensional stabilit…
Abstract The driving forces for the recent development of nanoscale features in conventional ceramic materials for both mechanical and functional reasons are discussed, and the causes of some of the resulting property enhancements are identified. Examples from the technical literature are examined, and the potential f…
Structure factors based on periodic density-functional (DFT) calculations on 25 molecular crystals have been used to evaluate trends in refined values of the kappa and kappa' expansion-contraction parameters of the Hansen-Coppens multipole formalism. As found previously and expected physically, the spherical-valence-s…
Abstract Dispersions of very small metal particles in polymeric matrixes are scientifically and technologically important. Here, poly( N ‐vinylpyrrolidone) (PVP) filled with nanometric silver particles characterized by a narrow size distribution and a controlled average dimension has been obtained using a modification…
Mesoporous and well-mixed Pt/Ru alloys (1:1 atomic ratio) were prepared by co-reduction of metal salts in the hexagonal liquid crystalline phase of a nonionic surfactant. Preliminary data indicate that oxidation of carbon monoxide by the mesoporous alloy is more facile than by a commercial platinum catalyst or by meso…
Ion bombardment of carbon materials is known to cause erosion with energies far below the threshold energy of physical sputtering, as well as at temperatures below the threshold of thermal desorption. Generally regarded as chemical sputtering, this effect, and factors contributing to it, are not well understood. We us…
In this paper we demonstrate, using density-functional tight-binding theory, that certain classes of silicon-based tubular nanostructures are stable and energetically viable. Specifically, we consider silicide and SiH nanotubes. The structures adopted by these nanotubes are very similar to those of previously reported…
We have calculated the low-field magnetic susceptibility $χ$ of a system consisting of non-interacting mono-dispersed nanoparticles using a classical statistical approach. The model makes use of the assumption that the axes of symmetry of all nanoparticles are aligned and oriented at a certain angle $ψ$ with respect t…