Materials Literature
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Very low molecular weight polyethylene (average MW 700 g/mole) magnetic nanocomposite particles were synthesized by nonsolvent and temperature induced crystallization along with ultrasonication. The particles are further coated with poly dl-lactic acid to functionalize the polyethylene particles for biomedical applica…
C 4 and C 5 cuts from FCC units can be useful in the preparation of oxygenates such as MTBE, ETBE, and TAME. Removal of the nitriles and diolefins present in these feedstocks is required to avoid poisoning of the etherification catalyst. Technological options include water washing and adsorption for nitriles and selec…
Chain extension reaction using water-soluble chain extenders was investigated with varying carbon number of the chain extenders (ethylene diamine, diaminobutane, and 1,6-hexane diamine) and their feed rates in the preparation of polyurethane dispersions using prepolymer method. The chain extension reaction between res…
It is expected that in the new century, to cope with developments of new high temperature technologies , a new generation of high performance refractory ceramics will e-merge and flourish which should include the following (1) oxide and nonoxide composites characterized by a unique combination of high hot strength , h…
Enoyl-CoA hydratase catalyzes the hydration of trans-2-crotonyl-CoA to 3(S)-HB-CoA, 3(S)-hydroxybutyryl-CoA with a stereospecificity (k(S)/k(R)) of 400000 to 1 [Wu, W. J., Feng, Y., He, X., Hofstein, H. S., Raleigh, D. P., and Tonge, P. J. (2000) J. Am. Chem. Soc. 122, 3987-3994]. Replacement of E164, one of the catal…
Abstract The objective of these investigations was to increase the use temperature of novel star‐block polymers consisting of a crosslinked polydivinylbenzene (PDVB) core from which radiate multiple poly(isobutylene‐ b ‐polystyrene) (PIB‐ b ‐PSt) arms, abbreviated by PDVB(PIB‐ b ‐PSt) n . We achieved this objective by…
Abstract We modified poly(epichlorohydrin) (PECH) with biphenyl carboxylic and naphthalene carboxylic acid derivatives which contains propargyloxy moieties. The linear polymers were characterized by NMR and IR spectroscopy, elemental analysis, DSC and TGA. We obtained only one side chain liquid crystalline. A smectic…
We constructed an optical plate-plate shear cell suitable for the study of aqueous suspensions of charged colloidal spheres under low electrolyte concentrations (10(-6) M). The variable gap height was adjusted to 30 microm corresponding to 15-30 interparticle distances. The concentration of 300 microm diameter polysty…
Abstract This study examined the oxygen‐transport properties of poly(ethylene terephthalate‐ co ‐bibenzoate) (PETBB55) crystallized from the melt (melt crystallization) or quenched to glass and subsequently isothermally crystallized by heating above the glass‐transition temperature (cold crystallization). The gauche–t…
Organic/inorganic hybrid solar cells have been constructed from titanium dioxide and zinc phthalocyanine (ZnPc). Only modest photocurrents are observed originating from excitation of the ZnPc. The photocurrent is not stable, but is found to decrease when measured in ambient atmosphere. The combined presence of oxygen,…
We demonstrate markedly enhanced adhesion between oxide ceramics and conducting metals via promoting open-shell electronic structure at the interface, by using a more covalent oxide or doping with early transition metals. Open-shell character suppresses closed-shell repulsions and permits local covalent and/or donor-a…
Abstract The mechanical properties of films prepared from model high‐glass‐transition‐temperature ( T g )/low‐ T g latex blends were investigated with tensile testing and dynamic mechanical analysis. Polystyrene (PS; carboxylated and noncarboxylated) and poly( n ‐butyl methacrylate‐co‐ n ‐butyl acrylate) [P(BMA/BA); n…
Silicone-in-fluorocarbon-in-water double emulsions were prepared by controlling carefully the characteristics of the emulsions composed of silicone, perfluoropoly-ethoxymethoxy difluorohydroxyethyl ether (PFPE–OH) and fluorosurfactant. In the emulsion formulation, PFPE–OH incorporated had a great influence on the drop…
A new synthesis of alcohol-soluble antimony-doped tin dioxide nanoparticles is described. The spectroelectrochemical behavior of nanocrystalline thin film electrodes prepared by dip coating from the colloidal solutions is investigated, and the applicability as an electrochromic device is demonstrated. Coloration resul…
Abstract The effects of reprocessing by extrusion for up to four cycles on the structure and mechanical properties of poly(trimethylene terephthalate) (PTT) were studied. Reprocessing did not change the chemical structure of the polymer but led to both yellowing and molecular weight reduction. Young's modulus and the…
BACKGROUND AND OBJECTIVES: Medical procedures, for example, laser angioplasty and extracorporeal lithotripsy as well as high-energy trauma expose human tissues to shock waves (SWs) that may cause tissue injury. The mechanisms for this injury, often affecting blood vessel walls, are poorly understood. Here we sought to…
The low-temperature liquid-liquid phase separation of the partially miscible hexane-nitrobenzene mixture imbibed in porous glasses of different pore sizes from 7 to 130 nm has been studied using 1H NMR (nuclear magnetic resonance) cryoporometry and pulse field gradient NMR methods. The mixture was quenched below both…
Abstract Damage to poly(vinylidene fluoride) was studied under uniaxial tension testing at different temperatures and strain rates. A satisfactory accuracy was reached with an original procedure for the assessment of the principal strains and volume strain. The semicrystalline polymer exhibited an increase in the volu…
Lead sulfide (PbS) nanocrystals with a particle size of 3.3 ± 0.7 nm have been synthesized in a poly vinyl alcohol (PVA) coating on fused silica glass substrates. The coating was dip-coated from a PVA aqueous solution, in which PbS nanocrystals were precipitated and stabilized in the polymer matrix. Third-order nonlin…
Abstract In the present study, blends of starch with different thermoplastics were prepared by a melt blending technique. The tensile properties and morphology of the blends were measured. It was found that with increasing starch content in starch/ionomer blends, the tensile strength and modulus increase. But for star…