Decisive Reaction Steps at Initial Stages of Photoinitiated Radical Polymerizations

摘要

Radical polymerization has been the focus of interest in terms of synthetic, technological, and mechanistic aspects. Many photoinitiating systems have been investigated, in which magnetic resonance methodologies were used as an exceedingly convenient tool to analyze the primary products. More recent developments in radical polymerization involve "living procedures",which result in a rather uniform molecular-weight distribution. Reversible addition/elimination steps are decisive for living radical polymerization procedures. Reversible steps in "classical" radical polymerizations have been established in the case of depolyme-rizations (decompositions)and during chain growth (also characterized by the ceiling temperature). Another important feature of photoinitiated radical polymerizations is the formation of benzaldehyde derivatives even at early stages of the polymerization.