Materials Literature
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Poly(lactic acid) is a new biopolymer material which is marketed by Cargill Dow Polymers under the tradename Nature Works*. One major application for this material is biaxially oriented films for food packaging because it possesses excellent barrier for flavor constituents, deadfold and heat sealability. Shrinkage mus…
Conductivity exhibiting power-law frequency response with an exponent of unity leads to frequency-independent dielectric loss. Such constant-loss (CL) behavior is not physically realizable over a nonzero frequency range, and approximate expressions that have been used to represent it are inconsistent with the Kronig–K…
A series of random copolyesters were synthesized by the bulk polycondensation of dimethyl terephthalate with ethylene glycol (EG) and trimethylene glycol (TMG) in various compositions. Their composition, molecular weight, and thermal properties were determined. The copolymers containing 22.2 mol-% ≤ TMG ≥ 46.0 mol-% a…
Abstract Ethylene‐vinyl alcohol copolymer(EVOH)/clay nanocomposites were prepared via a dynamic melt‐intercalation process. The phase morphology and the crystallization behavior of the nanocomposites were investigated, using DSC, DMTA, XRD and SEM. It was found that the treated clay content and dynamic processing time…
Abstract The objective of this investigation is to determine the effects of montmorillonite layered silicates on the curing kinetics of an epoxy resin. Differential scanning calorimetry was used to probe the changes in reactivity due to the presence of montmorillonite and due to the diamine hardener. The enthalpy of p…
In the present work, we have calculated the static and frequency-dependent polarizability tensors for a series of single-walled boron nitride nanotubes and compared them with corresponding results for carbon nanotubes. The calculations have been performed by employing a dipole−dipole interaction model based on classic…
The quasicrystal structure of primary intermetallic particles found in the ascast microstructure of a permanent mould-cast Mg-8wt%Zn-4wt%Al alloy has been characterized using transmission electron microscopy. Most primary intermetallic particles have an average composition of Mg
A connection is established between the crystal structures of borate minerals and the conditions (pH, log[H 2 O]) at which they are stable, using the approach developed by Schindler & Hawthorne (2001a, b). Structural units in borate minerals may be formally related by two types of chemical reactions, one of which cons…
Two 4-ns molecular dynamics simulations of calcium loaded calmodulin in solution have been performed, using both standard nonbonded cutoffs and Ewald summation to treat electrostatic interactions. Our simulation results are generally consistent with solution experimental studies of calmodulin structure and dynamics, i…
Abstract. Large strain plastic deformation of f.c.c. metals at low homologous temperatures results in the subdivision of monocrystals or polycrystal grains into mesoscopic fragments and deformation bands. Stage IV of single crystal work-hardening and the substructural contribution to the mechanical anisotropy emerge a…
Keine Neutralisation: Wie kann ein Reaktionsgefäß gleichzeitig eine Säure und eine Base enthalten, ohne dass sich diese neutralisieren? Eine Methode, die auf Sol/Gel-Materialien beruht, bietet einen Lösungsansatz für dieses Problem: Säuren und Basen werden in diesen Materialien immobilisiert, und organische Reaktionss…
CaCO3/polystyrene inorganic/organic composite nanoparticles (50 nm) with a core/shell structure were synthesized in 80% yield by emulsion polymerization. Nanometer CaCO3 was pretreated with γ-methacryloxypropyltrimethoxysilane in order to introduce polymerizable groups onto its surface. Soxhlet extraction experiments…
We report on a single-molecule study of a host-guest system that consists of a second-generation polyphenylene dendrimer and the cyanine dye Pinacyanol. The use of single-molecule spectroscopy enables us to obtain more detailed information on the properties of the host-guest system and can be used to confirm solution…
Static as well as dynamic electronic and vibrational longitudinal first hyperpolarizabilities ( and ) of α,ω,-nitro,amino-polyacetylene oligomers, containing up to 16 unit cells, have been computed at the Hartree−Fock and second-order Møller−Plesset levels using the 6-31G atomic basis set. The curve of first hyperpola…
The donor–acceptor complexes [Fe(C5H5){C5H4QNHM(NO)(TpMe,Me)X}] {TpMe,Me = tris(3,5-dimethylpyrazolyl)borate; Q = nothing, M = Mo, X = Cl, Br, I; M = W, X = Cl; Q = C6H4, M = Mo, X = Cl, Br, I; M = W, X = Cl; Q = CHCHC6H4 or NNC6H4, M = Mo, X = Cl), which contain 16-valence electron metal nitrosyl centres, [Fe(C5H5){C…
We examine the influence of strain fields in ZnO epilayers. We show that a reversal of the nature of the fundamental valence band can be observed similarily to what was reported in GaN epilayers.
A highly conducting polyaniline, doped with a Lewis acid, boron trifluoride, has been synthesized. Doping involves a transfer of the lone pair of electrons from the imine nitrogen of the polyaniline to the B center, leading to a change in the hybridization at the B site from sp2 to sp3. Various spectroscopic technique…
A study is made of the role of flaw state on the strength properties of brittle ceramic coating layers bonded to soft polycarbonate substrates. We introduce Vickers radial cracks at prescribed loads into the coating undersurfaces prior to bonding to control the sizes and locations of the starting flaws. A spherical in…
This article focuses on recent developments made in the field of siloxane and carbosiloxane dendrimers with the silicon atoms as the branching (1 → 2, 1 → 3, or 1 → 4) points. It attempts to treat in a comprehensive way the divergent growth method for the synthesis of Si–O- and Si–O–C-based dendrimers, including their…
A simple model is proposed for calculating a change in the electron work function caused by the adsorption of Cs atoms on the (111) rutile surface. The model takes into account both the dipole-dipole repulsion of adatoms and the adlayer metallization at large coverages. The results of the calculation using this model…