Effect of terbium(III) species on the structure and physical properties of polyurethane (TPU)

Herein, a study is presented, addressed to understand the influence of the terbium (III) species contained in a thermoplastic polyurethane (TPU) matrix. The studied terbium (III) species were terbium (III) nitrate, Tb(NO)·5HO, and a terbium (III) complex, [TbL (NO)](NO) (HO), where L is a macrocyclic ligand derived from 2,6-pyridinedicarboxyaldehyde and ethylenediamine. SEM-EDXS showed that in both films the terbium (III) species were homogeneously distributed in the polymer matrix. The film doped with the nitrate salt displayed different physical properties, in comparison to the pristine TPU and the film containing the terbium (III) complex. Both TPU/Tb films, exhibiting a green color emission, with a G/B ratio being temperature independent. By comparison of the emission of both films containing terbium (III) species, the TPU/Tb complex film presented a more intense luminescence due to the antenna effect. TPU doped with the nitrate salt showed weak emission, indicating the lack of sensitizing groups.
H.A.B. and P.F. thank to the projects ANID FONDECYT Iniciación 11200437 and ANID FONDECYT Iniciación 11200919, respectively, for the financial support. E.S., A.V. and D.V. thank Financiamiento Basal, AFB 180001 Project (CEDENNA). E.S., A.V., D.V. and P.F. acknowledge financial support from FONDECYT 1200033 Project. The authors also acknowledge the support from Brazilian agencies, CNPq and FAPEG and the State Research Agency of Spain (AEI) for a research contract (PID2019-107501RB-I00)