Benzylidene piperidones as photosensitizers for visible light photopolymerization

Abstract

Benzylidene piperidones (CZ-PD, TPA-PD, and PTZ-PD) with conjugated structure were synthesized by the aldol condensation of aromatic aldehyde and N-benzyl piperidone. These D-π-A-π-D dyes showed good visible light absorption and photosensitizing properties to iodonium salts in visible light-emitting diode (LED) photopolymerization. The photophysical properties of the synthesized structure were investigated via UV–vis spectroscopy and density functional theory (DFT) calculation. The mechanisms of structure-sensitized iodonium salts were explored through steady-state photolysis experiments. Polymerization experiments proved that these dyes with iodonium salt were an effective photoinitiating system for radical photopolymerization under visible LED light source and showed the ability to initiate deep curing.