Fast photopolymerization of acrylate coatings: Achievements and problems

Coatings chemists often prepare (meth)acrylate coatings which meet their needs. However, analysis of kinetics of photopolymerization (UV-cure) is usually based on a classical scheme of the chain free radical polymerizations. That set of reactions with respective rate constants is valid only up till few percent of conversion of double bonds. Multiple studies of photopolymerization are focused not on reactions at large degree of polymerization but on selection of new photoinitiators. In the present paper we focused on fundamentals of photopolymerization rather than on multitude of applications, different formulations, sources of light, etc., and we try to avoid repetition of widely discussed in the literature issues. A special attention is devoted to cage effect during photodissociation of initiators. An increase of cage effect value with a degree of polymerization increase affects overall efficiency of photoinitiator at large conversions. IUPAC terms and notions are suggested.