Materials Literature
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This research was undertaken to obtain new “BODIPY” dyes that fluoresce at relatively long wavelengths. The title compounds 1a − e were prepared via a divergent route involving Suzuki couplings of arylboronic acids to N - tert -butoxycarbonyl-4-bromopyrrole 2, condensation of the products with an acid chloride, and in…
Vinyl-functionalized MCM-41 samples were prepared by either a postsynthesis grafting (PSG) process or a direct co-condensation synthesis. The structures, stabilities, and reactivities of products from both methods were compared. The mesoscopic order of the hexagonal pore structure of vinyl-grafted MCM-41 (v-gr-MCM-41)…
The aromatic residues Phe-54, Phe-82, and Trp-116 in the hydrophobic substrate-binding pocket of Delta(5)-3-ketosteroid isomerase from Pseudomonas putida biotype B have been characterized in their roles in steroid binding and catalysis. Kinetic and equilibrium binding analyses were carried out for the mutant enzymes w…
Two series of polyether polyurethanes based on hydroquinone bis(β-hydroxyethy) ether (HQEE) or 1,4-butanediol (BDO) as a chain extender were prepared by a one-step bulk polymerization process. Their hydrogen bonding and morphological structure were studied by means of Fourier transform infrared spectroscopy (FTIR), di…
In this paper we study the static properties and the dynamical swelling behavior of thin spin-coated layers of natural polysaccharides on Si/SiO 2 substrates: the neutral and slightly branched dextran and the negatively charged, linear hyaluronic acid, by ellipsometric observation of the film swelling in a humidity-co…
Three novel bis(primary amine)iron(II) porphyrins [Fe(TPP)(RNH(2))(2)], where RNH(2) = 1-butylamine, benzylamine, and phenethylamine, have been synthesized and characterized by X-ray crystallography and IR, electronic, and Mössbauer spectroscopy. The compounds provide unprecedented structural data for the coordination…
Complexes of manganese(II)-containing aminoxyl radical substituted phosphine oxide ligands are reported. The compounds [(o-nitronyl nitroxide-phenyl)diphenylphosphine oxide]bis(hexafluoroacetylacetonato)manganese(II), 3, and bis{[(p-nitronyl nitroxide-phenyl) diphenylphosphine oxide]bis(hexafluoroacetylacetonato)manga…
Ovonyx, Inc. is developing a nonvolatile memory that is potentially denser, faster, and easier to make than Dynamic RAM. It relies on phase transitions induced by nanosecond heating and cooling of small region of the memory cell. Initial target markets are FLASH memory, Embedded memory, and DRAM.
We present a systematic study of how adsorption history affects the thickness, surface forces, and interfacial rheology of a model cationic polymer. The polymer was quaternized poly-4-vinylpyridine, QPVP (weight-average degree of polymerization n w = 325 and 98% quaternized with ethyl bromide). The main comparisons co…
Derivatives of quinolinium iodide have been found to exhibit second-order nonlinear optical (NLO) response in their crystalline form. The quaternary amine functionality is introduced as an electron-withdrawing group in NLO-active chromophores. While their electron-accepting capabilities are somewhat weaker than those…
Potassium titanate (K2Ti6O13) whisker treated with tetrabutyl orthotitanate was used to improve the mechanical and thermal properties of the poly(acrylonitrile–butadiene–styrene) (ABS) copolymer. The composites were prepared in a twin-screw extruder followed by injection molding. Static tensile measurements showed tha…
The polymerization of N-vinylcarbazole in the presence of FeCl3-impregnated montmorillonite resulted in the formation of a poly(N-vinylcarbazole)–montmorillonite composite. XRD analysis of the composite revealed no expansion for d001 spacing, in sharp contrast to that for the same composite prepared in the absence of…
A new kind of ultraviolet (UV)-curable waterborne polyurethane–acrylate (PUA) ionomer, prepared from toluene diisocyanate (TDI), polyethylene glycol (PEG), dimethylolpropionic acid (DMPA), triethylamine (TEA), and 2-hydroxyethyl methacrylate (HEMA), was synthesized by the modified prepolymer mixing process in which wa…
The effects of pH value of reaction system, reaction time, and reaction temperature on the chlorination reaction in the preparation of chlorinated natural rubber (CNR) from natural rubber latex were discussed. It has been found from the thermal analysis that the thermal degradation of CNR in nitrogen is a one-step rea…
The regenerated Antheraea pernyi silk fibroin films were prepared from calcium nitrate solution and crystallized with aqueous methanol solution. The structural and conformational changes were investigated by the X-ray diffraction method and infrared spectroscopy upon methanol treatment. The concentration and treatment…
Sulfur cured natural rubber vulcanizates were reclaimed by a vegetable product and diallyl disulfide under various reclaiming conditions. Progress of reclaiming was monitored by estimating the sol and gel portions, molecular weight determination of sol portions, and Mooney viscosity of reclaimed rubber. Tensile proper…
The thermostability and thermal decomposition kinetics of methyl cellulose (MC), ethyl cellulose (EC), carboxymethyl cellulose (CMC), hydroxyethyl cellulose (HEC), and hydroxypropyl–methyl cellulose (HPMC) were characterized in nitrogen and air by thermogravimetry (TG). Various methods of kinetic analysis were compare…
The use of heteroatom-substituted porphyrins in bioorganic and materials chemistry requires the ability to position a variety of substituents in a controlled manner about the porphyrin periphery. We describe a rational route to trans -AB 2 C-type porphyrins bearing one oxygen atom (N 3 O) or one sulfur atom (N 3 S) in…
A polylactide (PLA type LA 0200 K) was spun in high-speed melt spinning and spin drawing processes. The fibers were characterized with regard to the degree of crystallinity, the orientation, and the textile physical properties. The polymer was produced by a reactive extrusion polymerization process, and its hydrolytic…
Polypyrrole (PPy) grown from organic media and polymeric material produced by coelectropolymerization of pyrrole and aniline in organic acidic media were investigated by cyclic voltammetry, electrochemical impedance spectroscopy (EIS), differential scanning calorimetry (DSC), infrared spectroscopy (FTIR), scanning ele…