A novel direct coupling of simultaneous thermal analysis (STA) and Fourier transform-infrared (FT-IR) spectroscopy

Abstract

Evolved gas analysis (EGA) from thermal analyzers such as thermogravimetry (TG) or simultaneous thermal analysis (STA) which refers to simultaneous TG-DSC is well established since it greatly enhances the value of TG or TG-DSC results. The sensitive and selective FT-IR technique is in particular useful for the analysis of organic molecules but also for infrared active permanent gases evolved during most decomposition processes. The coupling interface between thermal analyzers and FT-IR spectrometers usually consists of heated adapters and a flexible, heated transfer line. In this work, a novel direct coupling of an STA instrument and an FT-IR spectrometer without a transfer line is presented. A very small FT-IR spectrometer is directly mounted on top of the STA furnace leading to a compact and fully integrated STA-FT-IR coupling system. The possibilities and the value of simultaneous STA-FT-IR measurements are demonstrated for organic, biomass, and ceramic samples in the temperature range between room temperature and about 1,500°C. Various samples from the field of inorganics and organics-especially polymers-were furthermore measured showing the advantages of the direct STA-FT-IR coupling compared to state-of-the-art STA-FT-IR coupling using a heated transfer line: we found that the time delay caused by the volume of the transfer line itself is rather negligible whereas a significantly better correlation between gas detection and TG results was observed in case of some highly condensable decomposition gases. Aspects of quantification of evolved gases are furthermore discussed as well as the known nonlinearity of FT-IR detection at higher gas concentrations.

pH-controlled Release System for Curcumin based on Functionalized Dendritic Mesoporous Silica Nanoparticles

“…Simultaneous Thermal Analysis (STA) coupled with Fourier Transform Infrared spectroscopy (STA-FTIR), is a powerful tool for qualitative analysis of the gases evolved during the desorption or pyrolysis process [64][65][66]. Sensitivity of the FTIR is in the microgram range, while for ST it is 1 ug [67].…”

Identification of polymers by means of DSC, TG, STA and computer-assisted database search

“…The latter is evaluated from the difference between the temperature-time curve during the sample measurement and the temperature-time curve where no sample is measured. Both TG and STA instruments are often coupled to evolved gas analysis techniques such as mass spectrometry (MS) or Fourier transform infrared (FT-IR) spectroscopy in order to enhance the possibilities for a material characterization [9]. Such coupled instruments are, however, not in the scope of this work.…”

Thermal decomposition studies of bio-resourced polyamides by thermogravimetry and evolved gas analysis

“…The coupled methods allow simultaneously not only to characterize the thermal behavior of the material, but also to identify on-line volatile components released during the measurement and thus to get an insight into the mechanism of decomposition. Studies on the thermal degradation of polyamides using TG couplings with IR, QMS, and GC/MS helped to understand their decomposition behavior and to postulate stabilization actions [11][12][13][14][15].…”