Detailed Analysis of an Unknown Polymer Using the Py-GC/MS System with Polymer Additives and F-Search Polymer Libraries

Significance of the Topic

Analysis of additives in polymers is key for material performance and safety in sectors such as automotive packaging and electronics

• Enables compliance with restrictive substance regulations
• Improves design of polymer formulations

Objectives and Overview

This study applied evolved gas MS thermal extraction and pyrolysis GC slash MS to identify the base polymer and additives in an unknown rubber sample by comparison with dedicated spectral libraries

• Determine polymer base material using F Search polymer library
• Characterize volatile and pyrolysis products to identify specific additives

Methodology and Instrumentation

A multi shot pyrolyzer EGA PY 3030D configured for EGA MS pyrolysis and thermal extraction and a GCMS QP2020 quadrupole instrument were used

1. Evolved gas MS analysis from 100 to 700 C at 20 C per minute
2. Pyrolysis GC slash MS at 600 C single shot mode
3. Thermal extraction GC slash MS heart cut mode from 100 to 340 C
4. Polymer additives library and F Search polymer library served for qualitative identification

Main Results and Discussion

Evolved gas MS thermogram revealed volatiles up to 340 C and polymer pyrolysates at higher temperature

• F Search polymer library matched styrene butadiene rubber at 97 percent similarity
• Pyrolysis GC slash MS confirmed styrene butadiene rubber match at 96 percent similarity

Thermal extraction GC slash MS in the volatile region identified four major additive peaks

• Peaks A and B identified as di n butylamine and butyl isothiocyanate originating from tributylthiourea antioxidant
• Peak C identified as N phenyl 1 4 benzenediamine pyrolysis product
• Peak D matched p p toluene sulfonylamido diphenylamine antioxidant known as Nocrac TD

Benefits and Practical Applications

The combined approach allows rapid estimation of both polymer base and additive composition without extensive expert interpretation

• Enhances reliability of quality control in polymer production
• Streamlines compliance testing for regulated chemical substances

Future Trends and Applications

Continued expansion of specialized libraries will support detection of emerging additives

• Integration with machine learning algorithms may accelerate spectral matching
• Advances in pyrolysis techniques will improve structural elucidation of complex additives

Conclusion

The use of a dedicated polymer additives library in tandem with a polymer library for evolved gas and pyrolysis MS provides a powerful toolset for detailed analysis of unknown polymer materials and their additive composition

References

• K D Jansson C P Zawodny T P Wampler J Anal Appl Pyrolysis 79 2007 353 361
• A Hosaka K Ito I Watanabe C Watanabe Shimadzu GC slash MS Technical Report No 9