Characterization of polysiloxanes by high-resolution pyrolysis-gas chromatography-mass spectrometry

Summary

Thermal degradation of various polysiloxanes was studied by pyrolysis-gas chromatography with a fused silica capillary column. The peak identification was carried out by a directly coupled gas chromatography-mass spectrometry system. Generally, polysiloxanes were thermally degraded to cyclic oligomers along with a small amount of the compounds formed through elimination and/or recombination of the pendent substituents. Most of the degradation products including possible stereo- and structural isomers were completely separated in the high-resolution pyrograms which reflect the original stereoregularities and sequence distributions in the polysiloxane chains. Furthermore, relative peak intensities of the characteristic cyclic oligomers observed were successfully interpreted in terms of the compositions of some kinds of siloxane copolymers.