{HEAD ~ at least one photosensitizer} which is effective to promote {TAIL ~ free radical polymerization} through bimolecular photochemical reactions of the energy donor type, the hydrogen abstraction type, or by formation of a donor acceptor complex with monomers or additives leading to ionic or radical species; and 
{ HEAD ~ at least one photosensitizer } which is effective to promote { TAIL ~ free radical polymerization } through bimolecular photochemical reactions of the energy donor type , the hydrogen abstraction type , or by formation of a donor acceptor complex with monomers or additives leading to ionic or radical species ; and
HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH REL REL REL REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH