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Characterization of a [(O3/2SiMe)x(OSi(OH)Me)y(OSiMe2)z] Silsesquioxane Copolymer Resin by Mass Spectrometry



R E. Tecklenburg, William E. Wallace, H Chen


Electrospray ionization Fourier transform ion cyclotron resonance (ESI FTICR) mass spectrometry and matrix-assisted laser desorption/ionization time-of-flight (MALDI-TOF) mass spectrometry were applied to a complex silsesquioxane-siloxane copolymer resin. The wide-polydispersity starting material was fractionated into 21 separate fractions in order to facilitate the analysis by mass spectrometry. ESI FTICR exact mass measurements were able to identify the specific oligomers present in the lowest mass fractions and showed that very few unreacted silanol groups remained, that is, topologically-closed structures predominated. MALDI-TOFMS was able to show that gel-permeation chromatography substantially underestimated the molecular masses of the higher mass fractions. Mass autocorrelation was able to show that the silsesquioxane monomer appeared only in even numbers in any given oligomer. This is a natural consequence of the highly condensed nature of the resin.
Rapid Communications in Mass Spectrometry
No. 22


autocorrelation, copolymer, exact mass measurement, mass spectrometry, resin, siloxane, silsesquioxane


Tecklenburg, R. , Wallace, W. and Chen, H. (2001), Characterization of a [(O<sub>3/2</sub>SiMe)<sub>x</sub>(OSi(OH)Me)<sub>y</sub>(OSiMe<sub>2</sub>)z] Silsesquioxane Copolymer Resin by Mass Spectrometry, Rapid Communications in Mass Spectrometry, [online], (Accessed February 25, 2024)
Created October 31, 2001, Updated October 12, 2021