文摘
Thermogravimetric analysis (TG) is a common technique to characterize the composition of polymers. To obtain more information about the decomposition products (and by this to get more information of the original composition of the original polymer), the TG is frequently coupled to a mass spectrometer (MS) and/or an infrared spectrometer (FTIR). However, TG–MS and TG–FTIR do not permit to identify the decomposition products separately. Especially with decomposition products present in low concentration, their identification by FTIR or MS is virtually impossible. This problem can be avoided by combing gas chromatography (GC) and MS. In this configuration, GC is used to separate different decomposition products that are then unambiguously identified by the MS. In the past, GC/MS coupled to TG offered only few GC injections or poor separation. A novel system includes a heated storage interface. This interface can store up to 16 gas aliquots collected at distinct temperatures during the course of a TG experiment. In this contribution, we present this new approach to combine a TG with a GC/MS. The potential of this novel combination is illustrated on the example of natural rubber samples with less than 10 % SBR content styrene–butadiene rubber (SBR). Using one SBR-specific decomposition product (styrene), quantification of the SBR content is possible. Also, emission profiles of in principle any decomposition product can be obtained and compared with the TG and the DTG curve.