Probing mobility constrains in polymers using 1H double quantum time domain NMR as a method to investigate thermal, chemical or environmental degradation effects.

We will discuss the application of 1H double quantum time domain NMR ( 1H DQTDNMR) to probe distribution of mobility constraints resulting from degradation of polymers. 1H DQTDNMR allows detecting the build-up of double quantum coherences, which can be associated to the density of points with some movement restriction in the sample. Applying this technic at temperatures where a solid phase is absent, the double quantum coherences can be associated to chain crosslinking or entanglement [1]. We will discuss the most common processing procedures, the limitations and advantages of the method considering the different polymer systems, for example elastomers, polymer melts and polymer composites. Finally, we will show examples on how this type of method can help to characterize the degradation process in constructing polymer such as polyamides.

Acknowledgements: PETROBRAS, CNPQ (grant 308760/2022-0) and FAPESP.

[1] Munaro, A. P., da Cunha, G. P., Filgueiras, J. G., Pinto, J. M., Munaro, M., de Azevedo, E. R., & Akcelrud, L. C. (2019). Ageing and structural changes in PDMS rubber investigated by time domain NMR. Polymer Degradation and Stability, 166. https://doi.org/10.1016/j.polymdegradstab.2019.06.008