Effect on photopolymerization of the structure of amine coinitiators contained in novel polymeric benzophenone photoinitiators

By the polycondensation of TDI with DATBP or AATBP, and different coinitiator amines, six novel thio-containing polymeric photoinitiators that contain a coinitiator amine and a side-chain or in-chain benzophenone (PUSBA or PUIBA) have been synthesized. FT-IR, H-1 NMR, and GPC analyses confirm the structures of all polymers. The UV-vis spectra indicate that the structure of the coinitiator amines has no significant influence on the maximal absorption. ESR spectra indicate that the polymeric photoinitiators that contain PDEA moieties can generate free radicals most efficiently. Three types of monomer with different functionality, EA, PPGDA, and TMPTA, are chosen to be initiated by these polymeric photoinitiators. The results show that the structure of the coinitiator amines has an important effect on the photopolymerization. For the PUSBA photoinitiators, the photoinitiator that contains N-phenyldiethanolamine as the coinitiator amine is the most efficient for EA, and that with N-butyldiethanolamine is the most efficient for both PPGDA and TMPTA. As for the PUIBA photoinitiators, that containing N-phenyldiethanolamine as the coinitiator amine is the most efficient for the polymerization of the three monomers.