Materials Literature
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Abstract Homogeneous esterification of cellulose with saturated fatty acids ( n ‐octanoic to n ‐octadecanoic) was accomplished with acetic anhydride co‐reactant in lithium chloride/ N,N ‐dimethylacetamide (LiCl/DMAc) medium. Cellulose mixed triesters (CMT) were obtained after 5 h at 130°C with an average of 2.2 acetyl…
We describe microstructural aspects of phase transitions between the lamellar (L), perforated layer (PL), and gyroid (G) morphologies in diblock copolymer melts. Using small-angle scattering, dynamic mechanical spectroscopy, and transmission electron microscopy, we show that these transformations proceed through the n…
The electrochemical reduction of oxygen on lanthanum manganite (LSM) electrodes has been investigated by cyclic voltammetry, alternating current (ac) impedance, and, in particular, potential step. An emphasis was given to the study of the kinetics of the formation of oxygen vacancy, which is shown to be the main cause…
Ultra-high-molecular-weight poly[(R)-3-hydroxybutyrate](P(3HB)) was biosynthesized from glucose by a recombinant Escherichia coli XL-1 Blue (pSYL105) harboring Alcaligenes eutrophus PHB biosynthesis phbCAB genes. Six kinds of P(3HB) samples with differ-ent weight-average molecular weight (Mw ) from 1.1 × 106 to 11 × 1…
We present neutron spin−echo and dielectric results on the local dynamics of polyisobutylene. The dielectric spectra reveal the existence of a so far unknown secondary relaxation process being distinctly different to previous theoretical predictions. Neutron spectra have been taken over a large range in momentum trans…
The sorption kinetics of 1,2-dichloroethane (DCE) (pure or dissolved in water at different concentrations) in amorphous and semicrystalline syndiotactic polystyrene films are studied by Fourier transform infrared spectroscopy. Experiments at low DCE concentrations show that the DCE sorption in empty clathrate samples…
The swelling behavior of a synthetic three-layer silicate caused by 12-aminolauric acid is studied by wide angle X-ray scattering. The swelling process as a function of the 12-aminolauric acid concentration can be separated into two regimes; i) cation exchange of inorganic cations by protonated 12-aminolauric acid and…
A series of highly conjugated tetrathiafulvalene (TTF) analogues with a quinonoid structure has been synthesized, and their structural and electronic properties have been characterized by both experimental techniques and quantum-chemical calculations. Cyclic voltammetry measurements show a two-electron oxidation wave…
Abstract A modified version of the Bertaut-Warren-Averbach (BWA) technique (Bertaut 1949, 1950; Warren and Averbach 1950) has been developed to measure coherent scattering domain (CSD) sizes and strains in minerals by analysis of X-ray diffraction (XRD) data. This method is used to measure CSD thickness distributions…
The one-pot biocatalytic synthesis of novel amphiphilic products consisting of an ethyl glucopyranoside (EGP) headgroup and a hydrophobic chain is described. The porcine pancreatic lipase (PPL) catalyzed ring-opening polymerization of ε-caprolactone (ε-CL) by the multifunctional initiator EGP was carried out at 70 °C…
Mechanisms operating in the exchange reactions occurring in the melt mixing processes of Bisphenol A polycarbonate (PC) with poly(butylene terephthalate) (PBT) and poly(ethylene terephthalate) (PET) blends have been investigated making use of appropriate polymer samples, capped or containing reactive chain end groups.…
Understanding the interaction forces that can act between particles and surfaces continues to be the focus of an extensive amount of research. While direct measurements of the force between molecularly smooth surfaces generally show good agreement with traditional models, experiments performed with more natural partic…
ε-Caprolactone was polymerized in bulk at 80°C with 2,2-dibutyl-2-stanna-1,3-dioxepane (DSDOP) as initiator. The reaction time was varied for monomer/initiator molar ratios of 20, 100 and 500. A rapid and complete conversion of the monomer and only slight transesterification or back-biting degradation were found after…
The optical properties of silicon nanocrystallites of known sizes, present in supercritically dried porous silicon films of porosities as high as 92%, have been measured by a variety of techniques. The bandgap and luminescence energies have been measured as a function of size for the first time. The bandgap increases…
WS2 microtubes, ribbons, and ropes are some of the unusual forms of inorganic crystals – grown by a chemical transport reaction – for which evidence is presented here. The Figure shows a WS2 rope composed of four nanotubes with one nanotube periodically wound around the widest tube. A further example, of two nanotubes…
A new chlorosulfonylated tetradentate beta-diketone, 4,4'-bis(1",1",1",2",2",3",3"-heptafluoro-4",6"-hexanedion-6 "-yl) chlorosulfo-o-terphenyl (BHHCT), was synthesized as a chelating label for Eu3+. BHHCT can be covalently bound to proteins under mild conditions and forms a strongly fluorescent chelate with Eu3+. Bov…
The shape fixity and recovery in a film of shape memory polymer of polyurethane series were investigated by the thermomechanical cycling tests with loading at various temperatures. The results are summarized as follows: (1) Strain is recovered at temperatures in the vicinity of the glass transition temperature Tg for…
We have investigated the unreconstructed (0001) surface structure of sapphire (α- Al 2 O 3 ) by grazing incidence X-ray scattering. Modulations along the crystal truncation rods were analyzed in order to determine the chemical nature of the terminating plane, and the structural relaxations of the first few atomic plan…
This paper constitutes a review of the control of toxic metal emissions using sorbents. The objective of sorbent-injection methods is to effectively capture the metal species (preferably transform it to an environmentally benign form) and to suppress the fraction in the submicrometer mode. The design of an effective s…
Single-molecule Raman spectroscopy of a cyanine dye in aqueous silver colloidal solution with the use of surface-enhanced Raman scattering at near-infrared excitation (NIR-SERS) is reported. A characteristic Poisson distribution of SERS signals due to the Brownian motion of single dye molecule-loaded silver particles…