A photoinitiated polymerisation reaction is defined by the author of this Rapra Review Report as a chain reaction in which the initiation step is produced by a photochemical event. This clearly differs from photocrosslinking, where every chain propagating step requires the absorption of light, although photoinitiated polymerisation of a multifunctional monomer will still lead to the production of a crosslinked network. Photoinitiated polymerisation reactions all fall into two categories: radical and ionic.

The main applications of photoinitiated polymerisation occur in the field of radiation curing (particularly UV curing). The benefits of such applications may include rapid curing, the elimination of pollution and solvents encountered in thermal drying technologies, versatility, enhanced product durability, low energy requirements, low temperature operation and small space requirements. Radiation curing may be encountered in many industries and product areas, including paints, coatings and varnishes, adhesives, graphic arts applications, photoresists for microelectronics, three dimensional modelling (stereolithography), dental and medical applications and direct laser imaging. This Rapra Review Report contains a review of the state of the art in photoinitiated polymerisation by Professor Jean-Pierre Fouassier, in which he makes reference to more than 500 key papers from the recent literature. This is published together with an indexed section containing bibliographic references and abstracts to the cited articles.

The review is divided into two main parts. The first part is devoted to a basic description of the different photoinitiation processes encountered. In the second part photopolymerisation reactions are presented and discussed. The main existing and potential applications of light curing technologies both in traditional industrial areas and in newly emerging high tech sectors are identified.