Materials Literature
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Graphite nanofibers are a novel material that is produced from the dissociation of carbon-containing gases over selected metal surfaces. The solid consists of very small graphite platelets, 30−500 Å in width, which are stacked in a perfectly arranged conformation. We have discovered that the material is capable of sor…
An aspect of metal oxides, colossal magnetoresistance exhibited by certain manganese oxides, in particular rare-earth manganates of perovskite structure, has received much attention in recent years. Some of these oxides show 100 per cent magnetoresistance, and have potential for technological applications. This text b…
Laser photolysis of nitritomanganese(III) tetraphenylporphyrin, Mn III TPP(ONO) ( 1 ), in degassed toluene gives manganese(II) tetraphenylporphyrin, Mn II TPP ( 2 ), plus NO 2 . The quantum yield, Φ, for the formation of Mn II TPP is dependent on the excitation wavelength: Φ = 0.045 at 355 nm and Φ = 0.0064 at 532 nm.…
Abstract Innovations in crystallographic instrumentation and the rapid development of methods of diffraction measurement have led to a vast improvement in our ability to determine crystal and molecular structure. This up-to-date resource will allow the reader to harness the potential of X-ray diffraction instruments.…
We report here the use of sulfonated fullerene derivatives and dendrimers with multiple −(O)SO 3 H groups as protonic acid dopants for polyaniline emeraldine base (PANI-EB). While doping of PANI-EB films with the sulfonated dendrimers gives conductivities up to ca. 10 S/cm, the hydrogensulfated fullerenol-doped materi…
Polymers with amidine groups NHCRN in the main chain were prepared by acid catalysed melt polycondensation of 4,4′-diaminodiphenyl methane (DAPM) with various orthoesters. The resulting polyamidines were characterized by 1H-, 13C- and 15N-NMR spectroscopy, differential scanning calorimetry (DSC), thermogravimetry…
The new one-dimensional quaternary thiophosphate K3CeP2S8 has been synthesized and structurally characterized. The structure consists of one-dimensional 1∞[CeP2S8]3- chains separated from one another by K+ cations. The linear chains are built upon an infinite 1D array of 9-fold sulfur coordinated CeIII polyhedra on wh…
Melt-miscible polymer blends of poly(ethylene oxide)/atactic poly(methyl methacrylate (PEO/a-PMMA)) were prepared by melt-mixing and characterized by pressure–volume–temperature (PVT) dilatometry in the pressure and temperature range of 0 to 200 MPa and 20 to 200°C, respectively. The PVT data were analyzed in terms of…
Cross-linkable poly[1-(trimethylsilyl)-1-propyne] (PTMSP) films were cast from toluene solutions containing PTMSP and either 4,4′-diazidobenzophenone or 4,4′-(hexafluoroisopropylidene)diphenyl azide. The composite films were clear and homogeneous and were cross-linked by UV irradiation at room temperature or thermal a…
A series of azobenzene chromophore-functionalized polyelectrolytes have been synthesized by a post-azo-coupling reaction. An epoxy-based precursor polymer (CH-AN) was synthesized by the reaction of 1,4-cyclohexanedimethanol diglycidyl ether (CH) with aniline (AN). For comparison purposes, another epoxy-based precursor…
We have developed epoxy-based, water-soluble azo polymers containing ionizable groups in the azobenzene functionality. We describe a novel approach of the noncentrosymmetric self-assembly of azobenzene chromophores in these polymers through a layer-by-layer deposition technique. The polymers in solution function as po…
Plasma polymer films were deposited from methyl methacrylate (MMA) vapor under various plasma conditions and XPS and FTIR used to study the changes to the compositions of the films as they were stored in air for longer than 1 year. The plasma power input per monomer mass unit (W/FM) markedly affected the composition o…
The authors have succeeded in fabricating low-loss tellurite-based Er3+-doped fibre for low noise 1.5 µm broadband EDFAs by developing high-purity TeO2 as a raw material. The background loss of the fibre is reduced to 0.054 dB/m at 1200 nm. A 20 dB signal bandwidth of 83 nm from 1528 to 1611 nm, and a low flat noise f…
We use light-scattering techniques to study the effects of methanol concentration on alkaline, cetyltrimethylammonium bromide (CTAB) water:methanol micellar solutions. We use X-ray diffraction, SEM, TEM, 29 Si NMR, and gas sorption measurements to study the structure, microstructure, and porosity of surfactant-templat…
Poly(L-lactic acid) filaments were prepared by high speed melt spinning at take-up velocities up to 5000 m/min. The crystallinity, birefringence, tensile strength, Young's modulus and yield strength all exhibit maxima at take-up velocities between 2000 and 3000 m/min. The boiling water shrinkage exhibits a minimum in…
Density functional calculations using the B3LYP, BP86, and FT97 functionals with an extended basis set are employed to investigate the mechanisms of H 2 oxidation by FeO + . Three mechanisms are considered, addition−elimination, “rebound”, and oxene-insertion. The oxene-insertion is characterized by high barriers and…
A high-pressure differential scanning calorimetric technique is described for studying polymer plasticization by compressed gases at pressures to 100 atm. The in situ measurements avoid problems due to gas desorption encountered with conventional DSCs, thus providing an accurate way to determine the change in glass tr…
The self-condensing vinyl polymerization of 4-(chloromethyl)styrene using metal-catalyzed living radical polymerization catalyzed by the complex CuCl/2,2′-bipyridyl has been attempted. Given the unequal reactivity of the two potential propagating species in this system, a variety of polymerization conditions were test…
Mesoporous titania and niobia molecular sieves were prepared by a ligand-assisted templating method. For comparison, titania samples were also prepared by simple hydrolysis and condensation of Ti alkoxide in the absence of templating agents. All materials were thoroughly characterized by UV−vis reflectance spectroscop…
Red and yellow soils from tropical regions are generally more mature than their subtropical counterparts. Most of these soils contain kaolin as the dominant clay mineral. Exchangeable aluminium (Al) generally balances permanent negative charges and occupies strongly acidic exchange sites of the soil clay. The objectiv…