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Chemical Processing (chemical + processing)

Distribution by Scientific Domains
Polymers and Materials Science50%
Chemistry33%

Selected Abstracts

Microbiological evaluation of toxicity of three polycyclic aromatic hydrocarbons and their decomposition products formed by advanced oxidation processes

ENVIRONMENTAL TOXICOLOGY, Issue 3 2003
Teresa Jamroz
Abstract The toxicity of benzo[a]pyrene, chrysene, and fluorene and their decomposition products formed by advanced oxidation processes (AOPs) was investigated using biotests with Escherichia coli and Vibrio fischeri. The polycyclic aromatic hydrocarbons (PAHs) were not highly toxic to either bacterial strain; the toxicity of their degradation products depended on the method of chemical processing. Inhibition of more than 27% was observed with products formed by oxidation of the PAHs, by AOP methods without hydrogen peroxide. Toxicity as high as 100% was observed after the combined action of hydrogen peroxide and other oxidizing agents. © 2003 Wiley Periodicals, Inc. Environ Toxicol 18: 187,191, 2003 [source]

Laser Spinning of Bioactive Glass Nanofibers

ADVANCED FUNCTIONAL MATERIALS, Issue 19 2009
Félix Quintero
Abstract The production of nanofibers of bioactive glass by laser spinning is reported. The technique yields a great quantity of free-standing fibers in the form of a mesh of disordered intertwined fibers. The method does not rely on chemical processing and does not need any chemical additive. It involves melting of a precursor material with tailored composition, which makes it possible to produce nanofibers from materials with which conventional melt drawing techniques cannot be used. Herein, the production of 45S5 Bioglass nanofibers is reported for the first time. The process is very fast (nanofibers of several centimeters are grown in a fraction of a second), without the necessity of post heat treatments, and no devitrification is observed as a result of the laser-spinning process. The morphology, composition, and structure of the nanofibers are characterized and an assessment of their bioactivity is carried out by immersion in simulated body fluid. This technique provides a method for the rapid production of dense glass nanofibers that can be employed as bioactive nanocomposite reinforcement, as a synthetic bone graft to replace missing bone, or to produce 3D structures for use as scaffolds for bone-tissue engineering. [source]

Nanotubular Mesoporous Bimetallic Nanostructures with Enhanced Electrocatalytic Performance

ADVANCED MATERIALS, Issue 21 2009
Caixia Xu
Catalytic functionalization of nanoporous copper generates a novel type of hierarchically hollow bimetallic nanocomposites, which show superior catalytic performance with greatly enhanced antipoisoning effect for methanol electro-oxidation. With the advantages of high catalytic performance, eco-friendly chemical processing, and low fabrication cost, these nanostructures hold great potential for important energy-saving technologies. [source]

Developing chiral surfaces for enantioselective chemical processing

AICHE JOURNAL, Issue 10 2009
David S. Sholl
First page of article [source]

High-pressure NMR characterization of triacetyl-,-cyclodextrin in supercritical carbon dioxide

MAGNETIC RESONANCE IN CHEMISTRY, Issue 2 2009
G. I. Ivanova
Abstract Cyclodextrins are used in many drug formulations since their cavities provide microenvironments where drug molecules can enter and form inclusion complexes for controlled drug delivery. Supercritical carbon dioxide (scCO2) is an alternative to organic solvents and a very attractive medium for the preparation of these inclusion complexes. The potential ability of triacetyl-,-cyclodextrin (TA-,-CD) to form inclusion complexes in addition to its high miscibility in liquid and scCO2 could offer a chance for an economical and environmental friendly chemical processing. In this work, high-pressure NMR studies were performed in order to obtain information on the molecular structure and dynamics of TA-,-CD in scCO2 at 313.15 K and 20 MPa and its ability to form inclusion complexes under these conditions was studied. The influence of scCO2 on a number of NMR spectral parameters, such as chemical shifts, spin-spin coupling constants, nuclear Overhauser effect (NOE) and spin-lattice relaxation (T1) has been studied. We unequivocally show for the first time structural changes of TA-,-CD in scCO2, like acetyl chain orientation and overall shape distortions that can affect its inclusion capability in this medium. The possibility of cavity self-closure is discussed and the results of two inclusion studies that support cavity self-closure, with the angiotensin-converting enzyme inhibitor, captopril, and the nonsteroid anti-inflammatory drug, flufenamic acid, are presented. Copyright © 2008 John Wiley & Sons, Ltd. [source]

Effectual dispersion of carbon nanofibers in polyetherimide composites and their mechanical and tribological properties

POLYMER ENGINEERING & SCIENCE, Issue 10 2010
Bin Li
The use of proliferation of nanotechnology in commercial applications is driving requirements for minimal chemical processing and simple processes in industry. Carbon nanofiber (CNF) products possess very high purity levels without the need of purification processing before use and are in growing demand for this quality. Polyetherimide (PEI) has excellent mechanical and thermal performance, but its high viscosity makes its nanocomposites processing very challenging. In this study, a facile melt-mixing method was used to fabricate PEI nanocomposites with as received and physically treated CNFs. The dispersion of CNFs was characterized by scanning electron microscopy, transmitted optical microscopy, and electrometer with large-area electrodes. The results showed that the facile and powerful melt-mixing method is effective in homogeneously dispersing CNFs in the PEI matrix. The flexural and tribological characteristics were investigated and the formation of spatial networks of CNFs and weak interfacial bonding were considered as competitive factors to enhanced flexural properties. The composites with 1.0 wt% CNFs showed flexural strength and toughness increased by more than 50 and 550%, respectively, but showed very high wear rate comparable with that of pure PEI. The length of the CNFs also exerted great influences on both mechanical and tribological behaviors. POLYM. ENG. SCI., 50:1914,1922, 2010. © 2010 Society of Plastics Engineers [source]