Inserting variable functional groups into a polymer backbone offers the possibility to carefully adjust the material properties of the polymer for tailored applications [1]. However, well-known controlled radical polymerization methods do not allow for the incorporation of all functional groups [2,3]. On the contrary, a promising strategy that introduces new value-added properties without destroying the parent backbone is the upcycling via direct chemical functionalization of commodity polymers, as it is depicted on Fig. 1 [4,5]. Accordingly, herein, new strategies for the upcycling of commercially available polydienes (particularly 1,4- polybutadienes) are explored. The first method targets a metal-free, novel electrophilic cascade reaction to decorate alkene functionalities within a lateral polymer chain with pendant bromine and amino-ether derivatives. The introduced pendant bromine groups serve as an intermediate to afford other chemical functionalities, thus opening vast possibilities for polymer post- functionalization. In this regard, the introduction of nitrogen functionality (i.e., via the amino-ether unit) without the use of intrinsically hazardous organic azide would be of great interest to the manufacturing sector. An alternative facile and atom-economical method is the metal-free chemo selective hydroamination of the commercially available unsaturated polymers. The resulting materials have tunable thermal and surface wetting properties as a function of both amine moiety and grafting density. By employing the aforementioned methods, we demonstrate viable solutions for the direct upcycling of polybutadienes along paving the way towards the future development of post-polymerization modifications on more complex elastomers (e.g., styrene-butadiene-styrene) and surface modifications of vulcanized rubbers.

References

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5. J. T. Offenloch, J. Willenbacher, P. Tzvetkova, C. Heiler, H. Mutlu, C. Barner-Kowollik Chem. Commun. 2017, 53, 775.

Acknowledgments

J. J. and H. M. acknowledges the University of Haute-Alsace (UHA) for the financial support from the French National Research Agency (ANR) with the reference “ANR-22-CPJ1-0077-01”. H.M acknowledges also the CNRS for a junior professorship contract. J.H. and H. M. acknowledge financial support from the Karlsruhe Institute of Technology, in addition to the Federal Ministry of Education and Research (BMBF) and the Baden-Württemberg Ministry of Science as part of the Excellence Strategy of the German Federal and State Governments.