Two hydrogen donor-containing naphthalimide benzyl thioether photoinitiators for LED photopolymerization

This work reports two hydrogen donor-containing naphthalimide benzyl thioether photoinitiators (NBT-HD1 and NBT-HD2), combining characters of one-component and two-component photoinitiators, for LED photopolymerization. They have good absorptions at emission wavelengths of LED and their epsilon max are more than or close to 1 x 104 M-1 cm-1. Both photoinitiators can generate radicals having initiating ability through not only the cleavage of C-S bonds, but also intermolecular hydrogen abstractions themselves under 405 nm LED irradiation. NBT-HD2 with acryloyl group presents an excellent capability of reducing oxygen inhibition. Moreover, NBT-HD1 or NBT-HD2/iodonium salt can trigger the cationic photopolymerization of the epoxide under 405 nm LED irradiation. More significantly, NBT-HD2 with acryloyl group exhibits a prominent migration stability in the polymer film and has broad application prospects in the field of food packaging and biomaterials.

Automated summary

This study introduces two novel photoinitiators for LED photopolymerization, with good absorption and initiating ability. Among them, NBT-HD2 with acryloyl group shows excellent capability in reducing oxygen inhibition and outstanding migration stability in polymer film.