Azodioxides as Inhibitors and Retarders in

摘要

Inhibitors are an important component of UV-curable adhesives. Active-center chain addition polymerizations are generally strongly exothermic. Inhibitors are used to control the reactivity of monomers avoiding runaway conditions. In addition, they also extend storage lifetimes and make purification and transportation possible. Azodioxides are used as free-radical inhibitors, not only due to their inherent inhibition/ retardation characteristics, but also because they possess the unique property to be thermally reversible between azodioxide and dinitroso structures. The azodioxide structure can sequester a hydronium ion formed from a photoacid generator (PAG), which can be subsequently released during thermal isomerization of the azodioxide to the dinitroso form.