MSD TIC chromatograms resulting from sequential pyrolysis of acrylate glue at increasing temperatures (450, 550 and 700 °C from bottom to top). [1) benzene; 2) toluene; 3) xylene; 4) styrene; 5) naphthalene; 6) 2-ethyl-1-hexene; 7) butylacrylate; 8) 2-ethylhexanol; 9) acetic acid, 2ethylhexylester; 10) 2-ethylhexylacrylate] At higher temperatures, aromatic compounds are present in increasing concentrations, indicating that secondarypyrolysis reactions are taking place.
Sequential pyrolysis is performed by analyzing identical samples under different pyrolysis conditions, for example increasing the pyrolysis temperature, pyrolysis duration or varying the split ratio.
The sequential pyrolysis procedure can be used for optimizing a pyrolysis method and it may lead to more detailed information on the sample because at lower temperatures there is less formation of secondary pyrolysis products. This means that in order to obtain information from primary pyrolysis of less stable compounds, the process may need to be performed at lower temperatures. If pyrolysis at low temperature does not lead to degradation of the more stable macromolecules in the sample, it must subsequently be performed at higher temperatures in order to get the information needed.
Sequential Pyrolysis features and benefits
- Pyrolysis of multiple identical samples in series under varying conditions
- Provides more in-depth information on unknown samples
- Easy method development
- Set-up of sequential pyrolysis methods by mouse-click using the GERSTEL MAESTRO Software
The Figure shows pyrograms of an acrylate glue obtained by sequential pyrolysis at different temperatures.
At higher temperatures aromatic compounds are present in the pyrograms at increasing concentrations, indicating that secondary pyrolysis reactions forming aromatic compounds, for example benzene, toluene or xylene, are taking place. As a result of this sequential pyrolysis study the best pyrolysis temperature for this sample is 450°C providing the most unadulterated view on the sample.
Unfortunately, the major peaks in the chromatograms show signs of column overloading and peak broadening. In coming experiments, the sample size should be reduced and a polar column phase used instead of the HP5 MS column that was used in this case.