Qualitative Profling of Co-polymer Polyethylene Terephthalate through Multifunctional Pyrolyzer-GC/MS by various Thermal Treatment Techniques

Significance of the Topic

Polyethylene terephthalate is widely used in packaging. Co polymer variants improve mechanical and barrier properties but complicate compositional analysis. Accurate identification of co monomer units and additives supports quality control recycling and regulatory compliance. Multifunctional pyrolyzer GC/MS techniques offer rapid and detailed qualitative profiling of complex polymer mixtures.

Study Objectives and Overview

• Integrate evolved gas analysis thermal desorption standard pyrolysis and reactive pyrolysis on a single platform
• Establish a workflow to distinguish different co PET samples
• Identify additives residual monomers and co monomer units

Methodology and Instrumentation

A workflow based on four thermal treatment techniques was implemented

• Evolved gas analysis GC/MS to map decomposition profile and define treatment temperatures
• Thermal desorption GC/MS for volatile additives and residual monomers
• Standard pyrolysis GC/MS at high temperature to generate backbone fragments
• Reactive pyrolysis GC/MS with tetramethylammonium hydroxide for methylation derivatization and selective hydrolysis

Used instrumentation

• Shimadzu GCMS QP2020 single quadrupole mass spectrometer
• Frontier Lab AS 1020E PY 3030D multi functional pyrolyzer
• Ultra alloy UAD TM 2.5N and ultra alloy 5HT GC columns

Main Results and Discussion

EGA revealed broad decomposition of co PET between 370 and 540 °C with a low temperature hump in one sample indicating additives

TD GC/MS of sample B released plasticizers including 1 3 isobenzofurandione and 2 2 4 trimethyl 1 3 pentanediol diisobutyrate confirming additive presence

Standard pyrolysis GC/MS generated common products benzene biphenyl vinyl benzoate and benzoic acid but failed to differentiate co polymer compositions

Reactive pyrolysis GC/MS produced methylated monomer and co monomer derivatives such as methylated ethylene glycol terephthalic acid neopentyl glycol 1 4 butanediol 1 6 hexanediol and 3 methyl 1 5 pentanediol enabling unambiguous sample discrimination

Repeatability studies yielded relative standard deviation below four percent for all key pyrolysates confirming method robustness

Benefits and Practical Applications

• Comprehensive profiling of polymer backbone and additives in a single analysis system
• Rapid qualitative identification of co monomer composition for quality assurance
• Supporting recycling and polymer authentication workflows

Future Trends and Potential Applications

Advances may include high resolution mass analysis coupling with chemometric data processing automated sampling and real time pyrolysis monitoring These developments will further enhance polymer profiling sensitivity and throughput

Conclusion

The integrated multifunctional pyrolyzer GC/MS workflow combining EGA TD standard and reactive pyrolysis provides a powerful and robust approach to qualitatively profile co polymer polyethylene terephthalate samples It enables clear identification of additives monomers and co monomer units essential for polymer analysis applications

References

• Awaja F Pavel D Recycling of PET European Polymer Journal 2005 41 1453 1477
• Brems A Baeyens J Vandecasteele C Dewil R Polymeric Cracking of Waste Polyethylene Terephthalate to Chemicals and Energy Journal of Air and Waste Management Association 2011 61 721 731
• Moldoveanu S Analytical Pyrolysis of Synthetic Organic Polymers Elsevier 2005