Analyzing Ethylene Vinyl Acetate by TG-MS

Thermogravimetric analyzers (TGA) combined with mass spectrometers (MS) are a popular method for studying gases that are evolved during a TGA analysis. This article demonstrates the application of TG-MS technology to measure the components of a gas evolved during the TGA analysis of ethylene vinyl acetate (EVA). EVA is used extensively in the production of solar panels and the foam used in footwear.

Experimental Procedure

A PerkinElmer^® Pyris™ 1 TGA using a standard furnace and alumina pans was used in this experimental study. Iron and nickel were used to calibrate the instrument and all samples were allowed to run under the helium purge. Depending on the sample being tested the rate of heating ranged from 5 to 40°C/min and between individual runs in air the furnace was allowed to burn off. All the samples used in this analysis weighed about 10 to 15mg.

The Pyris 9.0 software was used to perform data analysis and the PerkinElmer Clarus^® 600 C MS was used during the course of TG-MS analysis. In this TG-MS analysis a 0.1mm i.d. fused- silica transfer line, which was deactivated, was directly joined to the MS. This transfer line was then heated to a temperature of 210°C. Finally, the TurboMass™ GC/MS software was used to conduct data analysis.

Results and Discussion

In this experiment both EVA and the components of the gas were analyzed with TGA establish their identity. The thermogram from the TGA of EVA is shown in Figure 1. It shows two weight losses, which correspond to acetic acid and fragments of the polymer backbone respectively.

Figure 1. TGA curve generated from the analysis of EVA samples.

The evolved gas was subjected to MS analysis (Figure 2) which validated the identity of acetic acid with the spectral data shown in Figure 3.

Figure 2. The MS analysis of the evolved gas generated during the TGA of EVA.

Figure 3. Spectral data verifying the identity of the evolved gas from the first transition of the TGA as acetic acid.

Conclusion

TGA analysis helps in measuring a material’s weight loss at certain temperatures. The TGA-MS combination serves as a powerful technique that helps in identifying different species that evolve during thermal analysis.

This information has been sourced, reviewed and adapted from materials provided by PerkinElmer.

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