Nitro‐Carbazole Based Oxime Esters as Dual Photo/Thermal Initiators for 3D Printing and Composite Preparation

A series of Type I photoinitiators (PIs) based on a nitrocarbazole scaffold are developed and examined for the first time as visible light photopolymerization. Three oxime esters (OXE-M, OXE-V, OXE-P) varying by terminal groups (acetyl, acryloyl benzoyl) attached via ester group originally prepared. As result this, three PIs exhibit excellent photoinitiation abilities in presence acrylate monomers upon [email protected] 405 nm irradiation. Markedly, OXE-M exhibits better performance than benchmark phosphine-oxide (diphenyl(2,4,6-trimethylbenzoyl)phosphine oxide TPO). Chemical mechanisms supporting polymerization process with these investigated steady state photolysis, molecular orbital calculations real-time Fourier transformed infrared spectroscopy. After cleavage N─O bond decarboxylation, free radicals generated to initiate radical efficiently. Free photopolymerization is applied direct laser write 3D printing. Interestingly, thermal initiation behaviors can be used dual photo initiators. The highly opaque feature carbon fibers makes it difficult penetration, so photo/thermal curing here prepare fiber composites.