Materials Literature
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Abstract Measurements of the change of the pour point depression (Δ T PP ) were performed for the wax solutions made of four solvent mixtures: ethyl acetate/hexane (EA/HEX), 1,2‐dichloroethane/cyclohexane (DCE/CYH), butanone/heptane (MEK/HEP), and acetone/chloroform (AC/CF) doped with EVA polymers. The values of Δ T P…
Abstract The reaction of wheat straw hemicelluloses with succinic anhydride in aqueous alkaline systems was studied. The products showed a rather low degree of substitution, ranging from 0.017 to 0.21. The effects of reaction times of 0.5–16 h, temperatures of 25–45°C, and molar ratios of succinic anhydride to anhydro…
The preparation and crystal structure of 5-cyanofuran-2-[1,2,3,5-diselenadiazolyl], [RCN(2)Se(2)] (R = 5-cyanofuran), is reported. Crystal data for C(6)H(2)ON(3)Se(2): monoclinic, space group P2(1), a = 7.1121(7), b= 20.541(2), c =20.923(2) A, beta = 99.785(1) degrees, Z = 16. The crystal structure consists of diselen…
This paper describes the first successful application of the novel technique of X-ray microbeam diffraction to the study of wood cell walls in developing xylem tissue. The method enabled us to obtain quantitative diffraction diagrams from single cell walls. It was further combined with selected area electron diffracti…
Submonolayer Sn deposits on Pt(111) and Sn incorporated in a $(\sqrt{3}\ifmmode\times\else\texttimes\fi{}\sqrt{3})R30\ifmmode^\circ\else\textdegree\fi{}$ Sn/Pt(111) surface alloy were oxidized by ${\mathrm{NO}}_{2}$ under ultrahigh-vacuum conditions. The oxide films formed were characterized by Auger-electron spectros…
The dynamics of the fragile glass-forming orthoterphenyl have been investigated by transient grating experiments with an heterodyne detection technique. We measured the relaxation processes of this glass former over more than six decades in time with an excellent signal-to-noise ratio. Acoustic, structural, and therma…
We report ab initio calculations of quasiparticle lifetimes in graphite, as determined from the imaginary part of the self-energy operator within the GW approximation. The inverse lifetime in the energy range from 0.5 to 3.5 eV above the Fermi level presents significant deviations from the quadratic behavior naively e…
Low-dose−high-resolution electron microscopy (LD−HREM) was used to analyze the structure of regularly twisted poly( m -phenylene isophthalamide) (MPDI) strands formed by slow crystallization from solution. The MPDI chains were found to aggregate into regular assemblies exhibiting uniform twisting at several different…
Abstract In polymer blends, the composition and microcrystalline structure of the blend near surfaces can be markedly different from the bulk properties. In this study, the enzymatic degradation of poly(ε‐caprolactone) (PCL) and its blends with poly(styrene‐ co ‐acrylonitrile) (SAN) was conducted in a phosphate buffer…
Abstract A series of eight polyurethane elastomers was prepared using a two‐step bulk polymerization procedure to investigate the effect of the siloxane chain extender 1,3‐bis(4‐hydroxybutyl)1,1,3,3‐tetramethyldisiloxane (BHTD) on polyurethane properties and morphology. All polyurethanes were based on 40 wt % hard seg…
We use quantum-mechanical modeling to study the effect of local and long-range disorder on the incorporation energy, optical, IR, and XPS spectra of a peroxy linkage defect in amorphous silica $(a\ensuremath{-}{\mathrm{SiO}}_{2}).$ We discuss the methods to simulate amorphous structures and investigate to which extent…
Despite extensive investigation of Bombyx mori silk fibroin structures by many experimental methods, e.g., X-ray diffraction, molecular modeling calculation, and solid static 13 C NMR spectroscopy, a set of fingerprint structural parameters remains unavailable both for the silk I and the silk II forms. In this study,…
Abstract The interfacial reaction of the polyethylene (PE)/starch blend system containing the reactive compatibilizer maleated polyethylene (m‐PE) was directly characterized by Fourier transform infrared (FTIR) spectroscopy. A significant amount of anhydride groups on m‐PE existed as hydrolyzed forms, resulting in a l…
We study theoretically the thermodynamic properties and spin dynamics of a class of magnetic rings closely related to ferric wheels, antiferromagnetic ring systems, in which one of the Fe (III) ions has been replaced by a dopant ion to create an excess spin. Using a coherent-state spin path integral formalism, we deri…
A positive working low-molecular-weight photoresist based on partially t-Boc protected tetra-C-methylcalix[4]resorcinarene (t-Boc C-4-R) and a photoacid generator (PAG), diphenyliodonium 9,10-dimethoxyanthracene-2-sulfonate (DIAS) has been developed. t-Boc C-4-Rs were prepared by the reaction of C-4-R with di-tert-but…
We report Raman and x-ray diffraction studies of polycrystalline ${\mathrm{Ba}}_{x}{\mathrm{Sr}}_{1\ensuremath{-}x}{\mathrm{TiO}}_{3}$ (BST) prepared by the sol-gel technique in the range of $x=0$ to 1.0. Other than a tetragonal to cubic phase transition at composition $x\ensuremath{\approx}0.75$ of the BST powders de…
J. B. Pendry's "Negative Refraction Makes a Perfect Lens" is analyzed. It appears that several statements may be understood in terms of lens design but not in terms of fundamental behavior of light.
Abstract The postpolymerization of vinyl acetate (VAc)‐containing latexes with tert ‐butyl hydroperoxide (TBH)/ascorbic acid (AsA) as a redox initiation system was investigated. Volatile organic compounds (VOCs) such as acetone and tert ‐butyl alcohol were produced in this process. The influence of the TBH/AsA ratio,…
Abstract A series of poly(R‐3‐hydroxybutyrate)/poly(ε‐caprolactone)/1,6‐hexamethylene diisocyanate‐segmented poly(ester‐urethanes), having different compositions and different block lengths, were synthesized by one‐step solution polymerization. The molecular weight of poly(R‐3‐hydroxybutyrate)‐diol, PHB‐diol, hard seg…
Deposition of silane-based self-assembled monolayers onto mesoporous ceramic substrates has been found to be substantially faster from supercritical fluids than from typical condensed phase solutions. In addition, the monolayers so prepared display higher silane population density (6.5 vs 4.6 silanes/nm 2 ), fewer def…