Investigation of the Process In Photopolymerisation By TR-ESR And CIDNP Spectroscopy

Photo-polymerisation is a frequently utilized technology, which has found widespread use in the
coating, printing and electronics industry 1] 21. The fast acceptance of radiation curing in many
commercially important applications is due to remarkable advantages in terms of economy, ecology and product quality compared to thermal curing processes.

The photoinitiator is a key compound in all light curable formulations and is responsible for the transformation of light into chemical energy. The introduction of new raw materials and light sources, the development of novel applications as well as new legal regulations continuously impose new requirements on photoinitiators. Hence, the development of photoinitiators with properties which meet industrial needs is a continuous challenge.

Irradiation of the photoinitiator generally produces reactive species, e.g. radicals, which are able to induce a polymerization reaction (Scheme 1).