Materials Literature
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Hydrotalcite-like anionic clays of general formula [M(II)1–xM(III)x(OH)2]x+[CO32–x/2]x– · m H2O with M(III) = Al and M(II) = Mg, Ni, Zn have been prepared by precipitation of the hydroxycarbonates from the “homogeneous” solution after the thermally induced hydrolysis of urea. The effect of the temperature of precipita…
Ordered arrays, or superlattices, of metallic, insulating, or semiconducting quantum dots, represent an exciting new class of materials. These superlattices are often referred to as artificial solids, in which the nanocrystals take the place of atoms in traditional solids, and the packing arrangement of the nanocrysta…
CdTe nanoclusters were prepared in aqueous solution by the reaction between Cd 2+ and NaHTe in the presence of thioglycolic acid. Under reflux, the clusters start to crystallize and show a narrow band emission. The photoluminescence efficiency of CdTe nanocrystals strongly depends on the pH value of the colloidal solu…
Polymer nanocomposites, especially polymer-layered silicate (PLS) nanocomposites, represent a radical alternative to conventionally (macroscopically) filled polymers. Because of their nanometer-size dispersion, the nanocomposites exhibit markedly improved properties when compared with the pure polymers or conventional…
This review provides an overview of different aspects of inclusion chemistry in ordered mesoporous host materials such as MCM-41 or MCM-48 (Mobil codes). A rich field of inclusion chemistry has been explored in this context, including sorption, ion exchange, imbibition followed by reduction, grafting of reactive metal…
This review considers the uses of biodegradable polymers in terms of their relevance within current plastic waste management of packaging materials, biomedical applications and other uses; research papers and patents are catalogued. The chemical synthesis of polyesters and the microbial production of poly(hydroxyalkan…
Effects of size on predominantly mechanical properties of materials are reviewed at a first-order level. Microstructural constraints, e.g. due to second-phase particles and grain boundaries, and dimensional constraints in small-scale materials such as thin films are distinguished. Phenomena addressed are particle stre…
ZnO single crystal thin films were grown on c-plane sapphire using oxygen microwave plasma assisted molecular beam epitaxy. Atomically flat oxygen-terminated substrate surfaces were obtained by pre-growth cleaning procedures involving an oxygen plasma treatment. A two dimensional nucleation during the initial growth w…
Metal-insulator transitions are accompanied by huge resistivity changes, even over tens of orders of magnitude, and are widely observed in condensed-matter systems. This article presents the observations and current understanding of the metal-insulator transition with a pedagogical introduction to the subject. Especia…
Thermoplastic elastomer gels (TPEGs) composed of a poly[styrene-b-(ethylene-co-butylene)-b-styrene] triblock copolymer and a low-volatility, midblock-compatible mineral oil have been investigated at different oil concentrations to ascertain the effect of composition on TPEG morphology and mechanical properties. The im…
The ordered (-aacdbbdc-) polymer was prepared by the direct polycondensation of a pair of symmetric monomers (XabX), 4,4′-(oxydi-p-phenylene)dibutanoic acid (XaaX) and 2-methoxyisophthalic acid (XbbX), with a nonsymmetric monomer (YcdY), 4-aminobenzhydrazide, using the condensing agent diphenyl (2,3-dihydro-2-thioxo-3…
Miscibility and crystallization behavior of solution-blended poly(ether ether ketone)/polyimide (PEEK/PI) blends were investigated by using DSC, optical microscopy and SAXS methods. Two kinds of PIs, YS-30 and PEI-E, which consist of the same diamine but different dianhydrides, were used in this work. The experimental…
A study of the parameters that affect the Alder Ene reaction with respect to the synthesis of a terminally anhydride-functionalized polypropylene was carried out over a temperature range of 220–250°C using maleic anhydride concentrations of 2–12 mol equivalence with respect to the vinylidene group. As previously obser…
The vinyl groups in the pendant substituents of a series of poly(3-hydroxyoctanoate-co-3-hydroxy-10-undecenoate)s, PHOUs, were completely converted into epoxide groups with m-chloroperbenzoic acid to produce a series of copolymers, poly(3-hydroxyoctanoate-co-3-hydroxy-10,11-epoxyundecenoate)s, PHOEs containing 5, 9, 1…
The compound [Cr3O(OOCPh)6(py)3](py)ClO4 crystallizes in a lattice of threefold symmetry with the trichromium clusters forming equilateral trianges at 173 K, but at 1.5 K the neutron scattering spectrum indicates lower symmetry. Evidently the triangular clusters adopt nonequilateral structures which are concealed by r…
Supramolecular side-chain liquid crystalline polymers with various kinked pendant groups are constructed from positional isomers of proton acceptor monomers and donor polymers (with different molecular weights) through hydrogen bonding. Monomer−monomer complexes of similar structures are built to compare the influence…
Low-viscosity, methoxylated polysiloxane resins incorporating Me2SiO2/2 (D) and SiO4/2 (Q) units were prepared using nonhydrolytic condensation between Si—Cl and Si—OMe groups with the formation of MeCl, catalyzed by a Lewis acid. With the commonly used catalysts, condensation between two Si—OMe groups, with formation…
The miscibility, intermolecular interactions and thermal behavior of the poly(hydroxy ether of Bisphenol A) (Phenoxy)/poly(ethyl oxazoline) (PEOx) blends were investigated by differential scanning calorimetry (DSC), Fourier transform infrared spectroscopy (FTIR), and high-resolution solid-state nuclear magnetic resona…
New poly(amide–imide)s were prepared from a diimide–dicarboxylic acid, 1,4-bis(4-trimellitimidophenoxy)-2-tert-butylbenzene (BTTB), with various diamines by the direct polycondensation in N-methyl-2-pyrrolidinone (NMP) using triphenyl phosphite and pyridine as condensing agents. The new diimide–dicarboxylic acid BTTB…
The atomic force microscope (AFM) has been used to investigate morphological development during the crystallization of poly(ethylene oxide) (PEO) from the melt. PEOs with molecular weights of 1 × 105 and 7 × 106 were used. Height and amplitude images were recorded, using the tapping mode. For both polymers, the mode o…