Synthesis and characterization of a double photochromic initiator for cationic polymerization

A novel cationic photoinitiator carrying two photochromophoric groups was synthesized and characterized, and its photoinitiation activity was demonstrated. A novel cationic photoinitiator namely, 2-benzyl-2-(N,N-dimethyl-2-oxo-2-phenylethyl) ammonium hexafluoroantimonate-1-(4-morpholinophenyl)-butane-1-one (BDMPP+SbF6-), carrying two photochromophoric groups was synthesized and characterized. Theoretical absorption characteristics of the salt were studied and compared with those obtained experimentally. Photoinitiation activity of this salt was demonstrated by polymerization of various monomers at λ=350nm. Upon irradiation by UV light, cationic species formed from homolytic dissociation followed by electron transfer or directly by heterolytic scission initiate cationic polymerization.