Abstract: In this paper p-substituted diphenyl disulfides (DS) were used as initiators for photo-polymerization. The polymerization rates (R_r) of vinyl monomers increase in the order AN > MM A > St. Acrylonitrile is the most efficient one. The influence of DS structure, concentration of monomer and DS, and the nature of solvents are also studied. The steady and transient electron spectra measured indicate that the intermolecular complex in the ground state and in excited state are formed between DS and M in this system. The excited com-plex exhibits relative long lifetime and facilitates the radical photogeneration of DS. The mechanism of the primary photochemical process of DS was discussed.

Key words: Photopolymerization, initiation systems, aromatic disulfides