Photochemical Study of a New Bimolecular Photoinitiating System for Vat Photopolymerization 3D Printing Techniques under Visible Light

Catalysts

Patryk Szymaszek¹  Paweł Fiedor¹  Maciej Pilch¹  Joanna Ortyl¹  Anna Chachaj-Brekiesz²  Mariusz Galek³ 

[1] Faculty of Chemical Engineering and Technology, Cracow University of Technology, Warszawska 24, 31-155 Cracow, Poland;Faculty of Chemistry, Jagiellonian University, Gronostajowa 2, 30-387 Cracow, Poland;Photo HiTech Ltd., Bobrzyńskiego 14, 30-348 Cracow, Poland;

关键词: photopolymerization;    photo-redox initiating system;    3d printing;    additive manufacturing;    digital light processing;    stereolithography;    photosensitizers;    photo-reduction;    photo-oxidation;   

DOI  :  10.3390/catal10030284

来源: DOAJ

【 摘 要 】

In this work, we presented a new bimolecular photoinitiating system based on 2-amino-4,6-diphenylpyridine-3-carbonitrile derivatives as visible photosensitizers of diphenyliodonium salt. Real-time FTIR and photo-DSC photopolymerization experiments with a cycloaliphatic epoxide and vinyl monomers showed surprisingly good reactivity of the bimolecular photoinitiating systems under UV-A, as well as under visible light sources. Steady-state photolysis, fluorescence experiments, theoretical calculations of molecular orbitals, and electrochemical analysis demonstrated photo-redox behavior as well as the ability to form initiating species via photo-reduction or photo-oxidation pathways, respectively. Therefore, the 2-amino-4,6-diphenylpyridine-3-carbonitrile derivatives were also investigated as a type II free-radical photoinitiator with amine. It was confirmed that the 2-amino-4,6-diphenylpyridine-3-carbonitrile derivatives, in combination with different types of additives, e.g., amine as a co-initiator or the presence of onium salt, can act as bimolecular photoinitiating systems for cationic, free-radical, and thiol-ene photopolymerization processes by hydrogen abstraction and/or electron transfer reactions stimulated by either near-UV or visible light irradiation. Finally, the 2-amino-4,6-diphenylpyridine-3-carbonitrile derivatives were selected for 3D printing rapid prototyping experiments. Test objects were successfully printed using purely cationic photosensitive resin, created on a 3D printer with a visible LED light source.

【 授权许可】

Unknown