LAUSR

We investigated how the reactivity of epoxide and oxetane monomers in photoinitiated cationic polymerization is strongly influenced by their ability to form intramolecular hydrogen-bonding complexes with the Bronsted acids produced by the photoinitiator. In this paper, we highlight the importance of the thermal stability of the hydrogen-bonded complexes of the protonated monomers. We observed that the glycidyl ether structural motif (and its oxetane analog) is key for the formation of the complexes. Using temperature-controlled Fourier transform infrared (FTIR) with in situ ultraviolet irradiation, we performed a series of real-time FTIR experiments which support the hypothesis that the induction period is due to the thermal stability of the hydrogen-bonded complex. In particular, we focused on the photoinitiated cationic polymerization of bis(1-ethyl(3-oxetanil)methyl) ether (“di-oxetane”, DOX) for the thermal stability study because it exhibits a prolonged induction period. Furthermore, it was possible ...