A highly efficient polyurethane-type polymeric photoinitiator containing in-chain benzophenone and coinitiator amine for photopolymerization of PU prepolymers

A novel polyurethane-type polymeric photoinitiator (PUIOA) was synthesized through polycondensation of a novel diamine AAPBP, TDI and MDEA. The BP and coinitiator amine structures were successfully introduced into the backbones of PUIOA. A polymeric photoinitiator without the coinitiator amine in the polymer chain (PUIO) was also synthesized for comparison. FT-IR, H-1 NMR and GPC analyses confirmed the structures of polymeric photoiniiators. The UV-vis spectra of PUIOA and PUIO are similar to the parent AAPBP, and both exhibit high red-shifted, maximal absorption as compared with BP. ESR spectra indicate that PUIOA can generate free radicalsmost efficiently. Photopolymerization of the Polyurethane prepolymer, initiated by PUIOA, PUIO/MDEA, AAPBP/MDEA and BP/MDEA, was studied by photo-DSC. The results show that PUIOA is the most efficient photoinitiator for PU prepolymer.