Fourier Transform Infrared Spectroscopy Analysis (fourier + transform_infrared_spectroscopy_analysis)

Distribution by Scientific Domains

Selected Abstracts

Morphology Transformation of Hematite Nanoparticles Through Oriented Aggregation

Lili Wang
Hematite nanoparticles 30,45 nm in width and 15,25 nm in thickness were synthesized through oriented aggregation by a hydrothermal method. X -ray diffraction, transmission electron microscopy, high-resolution TEM, selected area electron diffraction, field emission scanning electron microscopy, and Fourier transform infrared spectroscopy analyses were applied to characterize the nanocrystals. Morphology transformation of these hematite nanoparticles from irregularly shaped to flower like with the assistance of oleic acid was surveyed. Based on these results, possible formation mechanism of the hematite nanoflowers is discussed here. [source]

Solid lipid microparticles produced by spray congealing: Influence of the atomizer on microparticle characteristics and mathematical modeling of the drug release

Nadia Passerini
Abstract The first aim of the work was to evaluate the effect of atomizer design on the properties of solid lipid microparticles produced by spray congealing. Two different air atomizers have been employed: a conventional air pressure nozzle (APN) and a recently developed atomizer (wide pneumatic nozzle, WPN). Milled theophylline and Compritol® 888ATO were used to produce microparticles at drug-to-carrier ratios of 10:90, 20:80, and 30:70 using the two atomizers. The results showed that the application of different nozzles had significant impacts on the morphology, encapsulation efficiency, and drug release behavior of the microparticles. In contrast, the characteristics of the atomizer did not influence the physicochemical properties of the microparticles as differential scanning calorimetry, Hot Stage microscopy, X-ray powder diffraction, and Fourier transform infrared spectroscopy analysis demonstrated. The drug and the lipid carrier presented in their original crystalline forms in both WPN and APN systems. A second objective of this study was to develop a novel mathematical model for describing the dynamic process of drug release from the solid lipid microparticles. For WPN microparticles the model predicted the changes of the drug release behavior with particle size and drug loading, while for APN microparticles the model fitting was not as good as for the WPN systems, confirming the influence of the atomizer on the drug release behavior. © 2009 Wiley-Liss, Inc. and the American Pharmacists Association J Pharm Sci 99:916,931, 2010 [source]

Short chain branching profiles in polyethylene from the Phillips Cr/silica catalyst

Paul J. DesLauriers
Abstract SEC and on-line Fourier transform infrared spectroscopy analysis have been combined to study branching profiles from the Phillips Cr/silica catalyst. For the first time, catalyst and reactor variables have been shown to affect the overall level and distribution of branches in polyethylene copolymers. Branching profiles from various chromium catalysts have been shown to vary from highly concentrated in the low MW end, to uniformly distributed over all of the MW range. Activation temperature and the presence of titania were highly influential. These observations, which have been used to gain insight into the chemistry of Cr/silica, explain much of the catalyst behavior that has for decades been used to optimize polymer properties. Trends in ESCR, impact resistance, and other physical characteristics, which were long attributed to changes in MW distribution, can now be seen to also be due in large part to changes in the branching profile. This knowledge should be of value in designing future resins. © 2007 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 45: 3135,3149, 2007 [source]

The Characterization of Automobile Body Fillers,

Sara C. McNorton M.S.
Abstract:, Body fillers are sometimes encountered with paint evidence from hit-and-run accidents. Little forensic research has been conducted and published on the subject since 1986. The objective of this study was to determine if chemical and physical differences in body fillers from various manufacturers existed and could be identified. Thirty-three samples of light-weight automobile body fillers and spot putties were obtained. The fillers and putties were compared using light microscopy, infrared spectroscopy, scanning electron microscopy with energy dispersive X-ray spectrometry (SEM-EDX), and pyrolysis gas chromatography (pyGC). Results from fourier transform infrared spectroscopy analysis placed the samples into five groups and differentiated six samples. Light microscopy placed the samples into one of five color groups. PyGC placed the samples into three groups and differentiated one sample. SEM-EDX placed the samples into four groups and differentiated 13 samples. Using these analysis methods, 19 of the 33 samples could be discriminated. The best discriminatory tool was found to be SEM-EDX. [source]