The Identification of High Polymers by Thermal Degradation in the Mass Spectrometer

Abstract

The polymers are thermally degraded in the high vacuum of a mass spectrometer at temperatures between 160–500°C. The mass spectra of the degradation products permit a clear identification on the basis of characteristic ions.

Using the spectra of 25 commercial products — polyethylene, polystyrene, polyvinyl chloride, polyamide etc. — the application of the method in polymer analysis is discussed.

Additives and residual monomers present in the polymer can be fractionally evaporated and separately investigated before thermal degradation.

Copolymers are differentiated from mixtures of the corresponding homopolymers by the occurrence of oligomeric fragment ions such as AAA⁺, AAB⁺ and ABB⁺. In some cases conclusions can be drawn regarding the distribution of monomer sequences in the copolymer, this is discussed using the copolymer vinylidene chloride/vinyl chloride as an example.