Photoinitiation of Ionic Polymerizations

At present, there is growing interest in industrial applications of photopolymerizations which refers mainly to surface coating processes proceeding via free radical mechanisms [1]. However, acrylate-and methacrylate-based formulations which are largely employed for this purpose exhibit disadvantages due to shrinkage and incomplete monomer conversion. It is hoped to overcome these problems with the aid of formulations containing substances of different chemical nature such as compounds containing epoxide groups. However, the latter can be polymerized only cationically and, therefore, the photoinitiation of cationic polymerizations has recently been the subject of intense investigations at various places in the world [2,3].