An insight into the anionic ring-opening polymerization with tetrabutylammonium azide for the generation of pure cyclic poly(glycidyl phenyl ether)

We evaluate the use of tetrabutylammonium azide (NNBu) as an anionic ring-opening polymerization initiator for synthesizing azide-terminated linear poly(glycidyl phenyl ether) and then generating monocyclic structures with high purity. In particular, we perform a detailed study on the end-group fidelity of polymers obtained by initiation with NNBu in the presence and absence of trisisobutylaluminum (iBuAl) and evaluate the purity of the cyclic structures obtained via copper-catalyzed alkyne-azide cycloaddition >click> reaction. We demonstrate that in contrast to the polymerization initiated by NNBu alone, the polymerization performed in the presence of iBuAl allows the formation of polymers with high end-group fidelity (azide groups at the α-position) for M < 20 kDa. The cyclic purity is evaluated by SEC with triple detection and dielectric spectroscopy. The latter technique, although not conventional for such a purpose, is shown to be very convenient to ensure cyclic purity in polymers showing an end-to-end dielectric relaxation mode.We gratefully acknowledge support from MINECO (MAT2015-63704-P) and Basque Government (IT-654-13).Peer Reviewe