Time-resolved filament pyrolysis

By scanning the temperature in a filament pyrolyser, the technique allows the separation of non-polymeric impurities from a polymer or composite material. Time-resolved filament pyrolysis has a series of useful applications as an analytical tool or even in some structure elucidations. As an example, it can be used [48] to differentiate the existence of more labile groups in a polymer structure. A typical variation of the total ion trace in a time-resolved pyrolysis MS for a composite material is shown in Figure 5.4.3. 

Figure 5.4.3. Total ion trace (TIT) of a time-resolved filament pyrolysis MS for a composite material.

Fast screening techniques, such as temperature-resolved in-source filament pyrolysis and laser-assisted pyrolysis, benefit from the high cycle time and mass accuracy of FUCR-MS [214]. An additional advantage of FUCR-MS in the study of pyrolysis processes is that MS can be readily used for structural identification of desorption and pyrolysis products. 

Other techniques utilize lasers for sample evaporation/pyrolysis and excitation such as laser induced desorption (LID) or laser microprobe mass analysis (LAMMA) (see e g. [1]). Some of the sample introduction procedures in Py-MS enhance the information obtained from Py-MS by the use of time-resolved, temperature-resolved, or modulated molecular beams techniques [10]. In time-resolved procedures, the signal of the MS is recorded in time, and the continuous formation of fragments can be recorded. Temperature-resolved Py-MS allows a separation and ionization of the sample from a platinum/rhodium filament inside the ionization chamber of the mass spectrometer based on a gradual temperature increase [11]. The technique can be used either for polymer or for additives analysis. Attempts to improve selectivity in Py-MS also were done by using a membrane interface between the pyrolyzer and MS [12]. 

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