The application of coupled techniques in the field of thermogravimetric analysis is well established, particularly for the investigation of the chemistry of thermal decompositions and identification of the evolved species.<br/>However, these techniques have limitations, especially when a large number of molecules are evolved simultaneously. For that reason a more comprehensive TG-GC-MS technique, which involves a separation of the evolving species by GC and identification by MS, became a necessity.<br/>A new TG-GC-MS line will be presented. The system includes an appropriate automated sampling loop that allows either injection of the gas stream in the GC column or releasing it outside the system. All gases evolving from the TGA furnace also flow through the sample loop so their concentration in the loop reflects the exact gas ratio in the furnace. The whole line, including the sampling loop is designed to withstand high temperatures and can be heated up to 350 °C.<br/>Two examples related to decomposition of polymers will illustrate how this technique that can give more in-depth understanding of the degradation of complex substances. The first example is a study of the thermal degradation of a copolymer of ethylene and 1-octene, which is known to result in a complex mixture of alkanes and alkenes. The second experiment shows the evolved gas anaylis of General Purpose PolyStyrene (GPPS) complete degradation. The resukts demonstrated that a presence of small quantities of heavy molecules with high boiling points (e.g. styrene dimer) can be detected in a gas flow rich in other substances.

Innovative TG-GC-MS methods for thermal degradation studies of polymers

251st National Meeting (2016)

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