Materials Literature
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Limited monomer solubility imposes very intriguing features on poly(p-phenylenebenzobisoxazole) polymerization. Only one type of functional group is detected at oligomer chain ends, and a high-molecular-weight polymer is obtained even when an excess of the monomer with low solubility is used. These remarkable phenomen…
We report an x-ray-scattering study of octahedral tilt ordering in the manganite series ${\mathrm{Pr}}_{1\ensuremath{-}x}{\mathrm{Ca}}_{x}{\mathrm{MnO}}_{3}$ with $x=0.4$ and 0.25 and in ${\mathrm{LaMnO}}_{3}.$ The sensitivity to tilt ordering is achieved by tuning the incident x-ray energy to the ${L}_{I},$ ${L}_{\ma…
We report image analysis of popping bubbles during the collapsing of two-dimensional (2D) and 3D aqueous foams. Although temporal and spatial correlations between successive popping bubbles within avalanches are emphasized, the breaking of a soap film at the air/foam interface seems to be independent of (i) the topolo…
Abstract The instability in water of poly(vinyl alcohol) (PVA)/poly(carboxymethyl cellulose) (CMC) was improved through radiation‐induced grafting with a styrene monomer. The PVA/CMC blend graft copolymer was used as a sorbent for dye wastes normally released from textile factories. The factors that may affect the sor…
Self-dynamics of water molecules has been studied in hydrated tricalcium silicate as functions of temperature, aging, and in the presence of an additive. A dynamical model taking into account the existence of "immobile water" and "glassy water" has been used to analyze quasielastic neutron spectrometer spectra. We ded…
Abstract Thermal analyses of poly(3‐hydroxybutyrate) (PHB), poly(3‐hydroxybutyrate‐ co ‐3‐hydroxyvalerate) [P(HB–HV)], and poly(3‐hydroxybutyrate‐ co ‐3‐hydroxyhexanoate) [P(HB–HHx)] were made with thermogravimetry and differential scanning calorimetry (DSC). In the thermal degradation of PHB, the onset of weight loss…
[reaction: see text] We report here the first heterogenization of a bis(oxazoline) ligand on an inorganic (silica) surface. The activity and enantioselectivity of this new material as a catalyst for the Diels-Alder reaction were checked, and it was shown that under certain conditions enantioselectivities similar to th…
Abstract The molecular structure of the copolyester formed through the interchange reaction in poly(ethylene terephthalate)/poly(butylene terephthalate) blends was investigated with 13 C‐NMR spectroscopy. The molar fractions of heterolinkage triads in the copolyesters were lower than the values calculated by Bernoulli…
The dynamics of interacting F centers resulting in F aggregates and nanocavities is modeled in thermochemically reduced MgO single crystals. We have recently shown that thermal annealing of thermochemically reduced MgO with an exceptionally high F-center concentration $(6\ifmmode\times\else\texttimes\fi{}{10}^{18}{\ma…
The helical structure of the chiral nematic phases induced by chiral dopants in nematic solvents provides a macroscopic image of the molecular chirality of the dopant promoted by the orientational order. Chiral biphenyls are challenging systems because their twisting ability shows a strong dependence on the molecular…
Saccharide functionalization of fourth through sixth generation PAMAM dendrimers is reported. A widely applicable MALDI-TOF MS procedure for the analysis of the degree of dendrimer surface functionalization that is achieved in a reaction is also described.
Glassy states have been observed in hard-spherelike colloidal suspensions; however, some recent work suggests that a stable, one-component hard-sphere glass doesn't exist. A possible resolution of this dilemma is that colloidal glass formation results from a small degree of particle polydispersity. In order to investi…
The basicity of oxide surfaces is often associated with surface lattice oxygen anions. CO 2 is the standard probe molecule for investigating surface basicity, but limited information is available in the surface science literature concerning its interaction with well-defined (single crystal) oxide surfaces. On stoichio…
Abstract In the present study, carbon fiber‐reinforced polylactide (C/PLA) composites with different interfacial conditions were prepared to determine the influence of interfacial adhesion strength (IAS) on in vitro degradation behavior of the C/PLA composites. Pure PLA and untreated and treated C/PLA composite sample…
Abstract Mechanical blends of ethylene–vinyl acetate copolymer and polyaniline doped with dodecyl benzene sulfonic acid (PAni–DBSA) were prepared in a two‐roll mill at 50°C and in a Haake internal mixer at 150°C. The effects of the blend composition and processing conditions on the electrical conductivity and mechanic…
Abstract The effect of diluents on isotactic polypropylene (iPP) membrane formation via thermally induced phase separation was investigated. The diluents were methyl salicylate (MS), diphenyl ether (DPE), and diphenylmethane (DPM). The cloud‐point curve was shifted to a lower temperature in the order iPP–MS, iPP–DPE,…
Abstract A new technology to synthesize trans ‐1,4‐polyisoprene (TPI) with bulk precipitation polymerization in the presence of a supported Ti catalysts was introduced. The termination of polymerization, stabilization of the polymer, and the adjustment of the molecular weight of TPI and its quality index are discussed…
We report new types of heterogeneous hydrogen-oxygen and silicon-oxygen branched chain reactions which have been found to proceed explosively after the filling of pores of hydrogen-terminated porous silicon (Si) by condensed or liquid oxygen in the temperature range of 4.2-90 K. Infrared vibrational absorption spectro…
The use of continuum phase-field models to describe the motion of well-defined interfaces is discussed for a class of phenomena that includes order-disorder transitions, spinodal decomposition and Ostwald ripening, dendritic growth, and the solidification of eutectic alloys. The projection operator method is used to e…
Quantum conductivity of single-wall carbon nanotube Y-junctions is calculated. The current versus voltage characteristics of these junctions show asymmetry and rectification, in agreement with recent experimental results. Furthermore, rectification is found to be independent of the angle between the branches of these…