Analysis of Base Material and Additives in Tire Rubber

Importance of the Topic

Automotive tire wear generates particles that combine rubber and road debris forming microplastics known as TRWP. These particles contain various additives including sulfur vulcanization accelerators that pose environmental hazards. Characterizing the base polymers and additives in tire rubber is essential for improving wear resistance and reducing microplastic pollution.

Objectives and Study Overview

This study aims to qualitatively identify the polymer base and sulfur containing additives in tire rubber. A combined approach using pyrolysis gas chromatograph mass spectrometer and flame photometric detector splitter enables simultaneous qualitative and selective analysis, following ISO TS 21396 pyrolysis GC MS protocol.

Applied Methodology

The analysis employs two stages. First evolved gas analysis by mass spectrometry heats samples from ambient to 700 C to generate thermograms and average mass spectra for polymer identification. Second thermal desorption GC MS with FPD detector splitting isolates and quantifies sulfur compounds. Sample preparation requires minimal handling by directly loading fragments into a pyrolyzer cup with fiberglass wool to prevent movement.

Instrumentation Used

• Multi shot pyrolyzer unit with auto shot sampler
• GC MS system model GCMS QP2020 NX
• Flame photometric detector model FPD 2030
• SMI flow device two way splitter with APC controller
• Columns UA DTM for EGA and SH Rtx 5SilMS for TD GC MS

Main Results and Discussion

EGA thermogram peaks between 370 and 500 C matched styrene butadiene rubber as the base polymer. A shoulder between 240 and 370 C indicated additive desorption. TD GC MS FPD splitting revealed four sulfur compounds including benzothiazole derivatives. MS library searches yielded similarity scores above 80 enabling confident identification of benzothiazole, 2 methylmercapto benzothiazole, 2 benzothiazolinone and 2 2 bibenzothiazole.

Benefits and Practical Applications

The combined FPD and MS approach allows high sensitivity detection of sulfur additives while providing qualitative mass spectral data in a single run. LabSolutions software simplifies complex splitter configuration. The method supports tire research and development, quality control in manufacturing, and environmental monitoring of TRWP.

Future Trends and Potential Applications

Advancements may include automated high throughput pyrolysis methods, expanded spectral libraries for diverse additives, integration with other selective detectors, and real time monitoring of tire wear in situ. These improvements will enhance understanding of microplastic release and accelerate sustainable tire design.

Conclusion

The integration of pyrolysis GC MS and FPD detector splitting presents a robust workflow for simultaneous identification of polymer matrices and sulfur based additives in tire rubber. This efficient approach reduces analysis time and enhances data quality for both research and industrial applications.

References

1 ISO TS 21396 2017 Rubber determination of mass concentration of tire and road wear particles TRWP in soil and sediments pyrolysis GC MS method