Hybrid organic-inorganic macromolecular photoinitiator system for visible-light photopolymerization

Abstract

Hybrid organic–inorganic macrophotoinitiator bearing pendant tertiary amine groups (OI-AH) was prepared by hydrolytic condensation of a silane containing amino groups. The macromolecular amino-functionalized photoinitiator was used in combination with camphorquinone (CQ) for visible-light photo-polymerization. The OI-AH was incorporated into methacrylate resins at loadings between 1 and 10 wt.%. The photodecomposition of the CQ/OI-AH in methacrylate monomers under visible light irradiation (λ = 470 nm) was examined. The photolysis products of CQ/OI-AH were transparent at the irradiating wavelengths; consequently, the consumption of the CQ is accompanied by increased light intensity in the underlying lays. The clean and rapid photobleaching of CQ in combination with OI-AH makes this photoinitiator system very attractive for polymerization of thick sections. The evolution of monomer conversion versus irradiation time showed that the OI-AH is an efficient co-initiator of CQ because a fast reaction and high conversion of methacrylate groups result after 60 s irradiation with a LED source of 140 mW.