Fluorine, organic samples

Berger, U., Barber, J. L., Jahnke, A., Temme, C., Jones, K. C.Analysis of Uuorinated alkyl compounds in air samples from England. In Fluoros An International Symeposium on Fluorinated Organics in the Environment, Toronto, Ontario, Canada, August 18-19, 2005. 

Some typical transmission electron micrographs of these polystyrene lattices are shown (Sample 2 and Sample 3) in Figure 10.6. The effects ofthe amount of stabilizer S is the relative amount of stabilizer) on the particle size is strong the more stabilizer applied, the smaller the particles are. It must be emphasized that this effective stabilization of nanopowders by our fluorinated block copolymers is not restricted to polymerization processes, but can be generalized to the fabrication of all organic nanopowders in media with low cohesion energy density, e.g., to the dispersion of dyes, explosives, or drugs. 

Total decomposition of the sample, the purpose of which is to release fluorine from inorganic or organic matrixes and convert it to fluoride ions, is usually a prerequisite for determining the amount of total fluorine. Commonly used procedures involve oxygen bomb combustion in a closed bomb [176,180], open ashing [181,182], alkali hydroxide or alkali carbonate fusion [151,183-187], pyrohydroly-sis [187-191], acid extraction [192,193] and microwave acid digestion [194-196]. 

Thermal treatment reduced surface carbon on aminopropylsilane-treated fiber, presumably by desorbing adventitious material. Carbon from the organic substituent on the silane desorbed also, since the nitrogen present before thermal treatment was totally absent afterwards. (The wide scan analysis of heat-treated fibers is incomplete because small concentrations of sulfur, fluorine and phosphorus were present on this sample only. They are considered to be artifacts, deposited perhaps from the inner wall of the chromatographic column during ramping, and are not reported). 

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