Materials Literature
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The molecular structure of the polyethylene oxide (PEO) molecular complexes with resorcinol (RES) and 2-methylresorcinol (two allotropic forms α-2MR and β-2MR) have been solved and refined by an X-ray diffraction technique (the “whole-pattern method”). The space group is Pna 2 1 for RES ( a = 10.54 Å, b = 10.18 Å, c =…
An analytical study is presented for the thermocapillary migration of a fluid sphere in a constant applied temperature gradient perpendicular to a planar surface. The Peclet and Reynolds numbers are assumed to be small, so that the appropriate energy and momentum equations of the fluids inside and outside the droplet…
Picosecond third harmonic generation (THG) spectroscopy in the range 0.9−2.4 μm (0.52−1.38 eV) and sum-over-states (SOS) theoretical modeling have been used to investigate the third-order nonlinear optical properties of a series of nine conjugated aromatic polyimines designed to elucidate structure−χ (3) relationships…
The vapor pressures of DyCl 3, DyBr 3, and DyI 3 were measured by the torsion method, and the following selected equations were derived in the covered temperature ranges. DyCl 3: log( p /kPa) = 9.31 ± 0.30 − (12523 ± 300)( K / T ), (924−1214 K). DyBr 3: log( p /kPa) = 11.47 ± 0.30 − (14344 ± 300)( K / T ), (878−1151 K…
A hydrogenation process has been developed to recover carbon black from rubber crumbs prepared from scrap tires. A semi-batch 2 L autoclave was used, with hydrogen continuously bubbled through a slurry of rubber crumbs and a paraffinic dissolution oil under pressures from 300 to 1500 psig and temperatures of about 400…
The methanol-soluble extracts of the roots of Cynanchum wilfordii showed a significant multidrug-resistance-reversing activity, and four known pregnane glycosides were isolated by bioassay-directed fractionation and separation. Their structures were identified as gagaminin 3-O-beta-D-cymaropyranosyl-(1-->4)-beta-D-ole…
Montmorillonite clay fine particles containing alkylammonium or pyridinium guests have been observed to be highly dispersed and aligned in thin films of sol−gel polysilicate networks spin-coated on quartz slide glasses. Polarized UV and visible spectroscopic analyses of the films indicate that the organic guests are a…
Waste polystyrene containing additives was converted into a polymeric flocculant by a chemical modification. Specifically, waste polystyrene and waste high-impact polystyrene (HI-PS) containing rubber components or a coloring agent were sulfonated to produce a water-soluble polymer whose molecular weight ranged from 4…
Some ultrahigh molecular weight polyethylenes have been shown to be highly ductile but only under specific conditions. When the initial starting state is reactor powder, the ductility is presumed to be due to the low initial entanglement. Samples were prepared for such draw by compression molding of reactor powder tha…
Two kinds of FSM-type mesoporous silicas with different OH densities were prepared by calcination and acid treatment and modified with various silylating agents. The density of silanol groups in acid-treated FSM was about 1.5 times as large as that in calcined FSM (2.4 OH groups nm - 2 ), determined by thermogravimetr…
We have synthesized and evaluated five series of polymeric gadolinium chelates which are of interest as potential MRI blood pool contrast agents. The polymers were designed so that important physical properties including molecular weight, relaxivity, metal content, viscosity, and chelate stability could be varied. We…
A series of alkali metal-exchanged zeolites X and Y co-exchanged with small amounts (1 per unit cell) of methyl viologen (MV 2+ ) were prepared. The diffuse reflectance UV−vis spectra of the dried zeolites showed broad absorption bands in the 220−320-nm region. Decomposition of the bands revealed that each absorption…
Atomic force microscopy was used to study the surfaces of oxygen-plasma-treated polypropylene (PP), kraft pulp, filter paper, and wood. The effect of plasma treatment on the adhesion properties between PP film and wood was evaluated by means of a peel test. The highest adhesion to wood resulted from the shortest treat…
ADVERTISEMENT RETURN TO ISSUEPREVNoteNEXTDesign of New Organic Gelators Stabilized by a Host−Guest InteractionKazuhiko Inoue, Yoshiyuki Ono, Yasumasa Kanekiyo, Tsutomu Ishi-i, Kanami Yoshihara, and Seiji ShinkaiView Author Information Chemotransfiguration Project, Japan Science and Technology Corporation (JST), 2432 A…
Ideas developed to describe the simulated glass transition in simple models, like hard spheres, are applied to real materials in which temperature, rather than density, is the important variable. The free energy of a liquid is expressed in terms of the free energy of all the glasses that it samples. The assumption tha…
Platinum nanoparticles were prepared in an aqueous system using high-intensity ultrasound (200 kHz, 6 W cm - 2 ). The particles formed in the presence of a surfactant (sodium dodecyl sulfate, SDS) were stable, homogeneously spherical, and relatively monodispersed with an average 2.6 nm diameter. The rate of formation…
Novel thermosensitive poly(organophosphazenes) bearing methoxy-poly(ethylene glycol) (MPEG) and amino acid esters as substituents have been synthesized, and their lower critical solution temperature (LCST) was investigated. Differential scanning calorimetry (DSC) has shown that some of the polymers exhibit crystallini…
ADVERTISEMENT RETURN TO ISSUEPREVCommunication to the...Communication to the EditorDiscrete Yttrium(III) Complexes as Lactide Polymerization CatalystsBradley M. Chamberlain, Yongping Sun, John R. Hagadorn, Eric W. Hemmesch, Victor G. Young, Maren Pink, Marc A. Hillmyer, and William B. TolmanView Author Information Dep…
A method of preparing liquid crystal devices by phase separation of liquid crystal from its solution in a prepolymer, which results in adjacent layers of liquid crystal and polymer, is described. Liquid crystals in these phase-separated composite films exhibit electro-optical properties not observed in devices prepare…
The kinetics of the sonolytic degradation of aqueous solutions of carbon tetrachloride and hexachloroethane (C 2 Cl 6 ) were investigated at six different frequencies over the range from 20 to 1078 kHz. The rates of degradation of CCl 4 and C 2 Cl 6 were shown to increase with increasing frequency with optimal degrada…