AbstractA special way of coupling a thermobalance and a quadrupol mass spectrometer proved to be a source of complex information on the structure and degradation of polymers. Two typical examples—polypropylene and polyquinone—were investigated. The most important new findings in the case of polypropylene were connected with the influence of the layer thickness on the thermal stability and the formation of volatile products. New light could be thrown on the mechanism of degradation based on the results. In the case of the new polymer, polyquinone, the effect of the imperfections of structure could be well separated from the basic process of thermal breakd