The structure of some olefin-carbon monoxide copolymers and terpolymers has been investigated by analyzing the fraction of lower oligomers remaining in the reaction solvent as solutes. Analyses were conducted by introducing one muL of these diluted solutions into the ion source of a mass spectrometer and recording their desorption chemical ionization mass spectra (DCI-MS). Although some features of the polymer structure might not appear in the low oligomers (i.e. the relative abundance of monomers), the present characterizations highlight the main structural aspects of synthetic interest and provide insight into the reaction mechanism. DCI-MS proves useful in supplying detailed information on terminal groups, nature of monomers, their linkage (alternate versus block copolymers), molecular weight distribution. The presence of unsaturated terminal groups conjugated with a CO monomer can be selectively evidenced by recording the spectra in the negative ion mode, while positive ion spectra provide a non-selective description of (protonated) sample constituents.
Analytical Characterization of Ethylene-Propylene-Carbon Monoxide Copolymers by Desorption Chemical Ionization Mass Spectrometry
VINCENTI, Marco;
1993-01-01
Abstract
The structure of some olefin-carbon monoxide copolymers and terpolymers has been investigated by analyzing the fraction of lower oligomers remaining in the reaction solvent as solutes. Analyses were conducted by introducing one muL of these diluted solutions into the ion source of a mass spectrometer and recording their desorption chemical ionization mass spectra (DCI-MS). Although some features of the polymer structure might not appear in the low oligomers (i.e. the relative abundance of monomers), the present characterizations highlight the main structural aspects of synthetic interest and provide insight into the reaction mechanism. DCI-MS proves useful in supplying detailed information on terminal groups, nature of monomers, their linkage (alternate versus block copolymers), molecular weight distribution. The presence of unsaturated terminal groups conjugated with a CO monomer can be selectively evidenced by recording the spectra in the negative ion mode, while positive ion spectra provide a non-selective description of (protonated) sample constituents.
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