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APPLICATIONS OF FUSION REACTION GAS CHROMATOGRAPHY AND PYROLYSIS GAS CHROMATOGRAPHY TO THE CHARACTERIZATION OF POLYSILOXANES AND POLY-M - CARBORANYLSILOXANES
Abstract
The technique of alkali fusion reaction gas chromatography has been applied to the analysis and characterization of polycyanoalkylsiloxanes, polyalkoxysiloxanes, and poly-m-carboranylsiloxanes. A reaction system was designed to allow the efficient and quantitative conversion of the organo-functional and silicon-functional groups to products sufficiently volatile for gas chromatographic analysis. Milligram or less quantities of material were reacted at elevated temperatures in a flowing inert atmosphere for periods of 15 minutes or less. Upon completion of the reaction, the cryogenically trapped fusion products were flash volatilized onto the gas chromatograph column for separation and quantitation. A mini volume switching valve allowed the simultaneous occurrence of polymer fusion and product chromatography of a previous fusion. The average percent relative standard deviation was 1.2%. The thermal degradation properties of the poly-m-carboranylsiloxanes were studied by pyrolysis gas chromatography encompassing the ancillary techniques of selective element detection and mass spectroscopy. A gas chromatograph was interfaced with an atmospheric pressure microwave induced and sustained plasma emission detector for boron pyrolyzate analysis and an atmospheric pressure d.c. argon plasma emission echelle spectrometer for silicon pyrolyzate analysis. The use of selective element detection simplified the interpretation of the complex pyrograms and facilitated the mass spectral determination of the pyrolyzate structures. The thermal degradation of the poly-m-carboranylsiloxanes cannot proceed through an intramolecular cyclization pathway due to the steric restraints imposed by the presence of the carborane cage in the siloxane backbone. It was postulated that the m-carboranylsiloxanes depolymerize by an intermolecular pathway; the presence of cyclic siloxane pyrolyzates was shown to be consistent with this pathway.
Subject Area
Analytical chemistry
Recommended Citation
SARTO, LOUIS GEORGE, "APPLICATIONS OF FUSION REACTION GAS CHROMATOGRAPHY AND PYROLYSIS GAS CHROMATOGRAPHY TO THE CHARACTERIZATION OF POLYSILOXANES AND POLY-M - CARBORANYLSILOXANES" (1982). Doctoral Dissertations Available from Proquest. AAI8229603.
https://scholarworks.umass.edu/dissertations/AAI8229603