/pdf/recent-advances-on-benzylidene-ketones-as-photoinitiators-of-1m9twtev.pdf

Recent Advances on Benzylidene Ketones as Photoinitiators of Polymerization

http://manuscript.elsevier.com/S0014305722000155/pdf/S0014305722000155.pdf

How to overcome the light penetration issue in photopolymerization? An example for the preparation of high content iron-containing opaque composites and application in 3D printing

/pdf/recent-advances-on-benzylidene-cyclopentanones-as-visible-2e6ywo3d.pdf

Recent Advances on Benzylidene Cyclopentanones as Visible light Photoinitiators of Polymerization

In both organic and polymer synthesis, photochemistry of Charge Transfer Complexes (CTCs) is considered as a powerful approach to expand visible-light-driven radical chemistry reaction. We report herein on the development of a class of useful CTCs using pyridinium salts as efficient electron acceptors (combined with N, N, 3, 5-tetramethylaniline, TMA) to achieve a multi-wavelength (375-560 nm) metal-free LED photopolymerization process under mild conditions (open to air, without monomer purification and inhibitor removal). The UV-vis absorption spectra and molecular modeling simultaneously verified its potential blue-green absorbing wavelength range. Also, their good thermal initiation behavior at relatively low temperature makes it easier to achieve thick samples and/or polymerization in the shadow region in practice. More importantly, with excellent photoinitiating capability, the formulation was successfully applied to direct laser write (DLW) and high-resolution 3D printing, yielding series of objects with well-defined structures, such as letters, ring, solid square and chess piece. These new pyridinium salt acceptors further extend the applicability to visible photopolymerizable resins and additive-containing formulations for efficient surface and deep curing. This article is protected by copyright. All rights reserved.

Charge Transfer Complexes (CTCs) with Pyridinium Salts: Towards Efficient Dual Photochemical/Thermal Initiators and 3D Printing Applications.

In this study, photoinitiated cationic polymerization of epoxy resins by photoinduced electron transfer reactions using four new chromophoric dyes, namely (3E)-1,1′-bis(2-ethylhexyl)-6,6′-dipyren-1-yl-3,3′-biindole-2,2′(1H,1′H)-dione (ISOIV), (3′E)-1,1′′′-diethyl-1′,1′′-bis(2-ethylhexyl)-1H,1′′′H-5,6′:3′,3′′:6′′,5′′′-quaterindole-2′,2′′(1′H,1′′H)-dione (ISOV), (3E)-6,6′-bis(9-ethyl-9H-carbazole-3-yl)-1-[(2R)-2-ethylhexyl]-1′-[(2S)-2-ethylhexyl]-3,3′-biindole-2,2′(1H,1′H)-dione (ISOVIII) and 3,3′-(6-bromokinoksalin-2,3-diyl)bis(9-ethyl-9H-carbazole) (TPDC6), and diphenyliodonium hexafluorophosphate (Ph2I+PF6−; DPI) under sunlight is reported. Upon irradiation, photoexcited dye forms an exciplex with DPI. Electron transfer reactions within the exciplex result in the formation of ionic species capable of initiating ring-opening polymerization of an epoxy resin. It is shown that among the investigated dyes, ISOVIII and TPDC6 exhibited higher initiation efficiency in accordance with their stronger electron-donating nature due to the presence of carbazole groups. © 2021 Society of Industrial Chemistry. 

Highly conjugated isoindigo and quinoxaline dyes as sunlight photosensitizers for onium salt‐photoinitiated cationic polymerization of epoxy resins

Imidazole based dual photo/thermal initiators for highly efficient radical polymerization under air with a metal-free approach

Synergistic Approach of Type I Hybrid Complexes for highly efficient Metal-based Initiating Strategies: Toward low energy-consuming polymerization for Thermoplastic Composite Implementation

Marie Le Dot

Papers

How to overcome the light penetration issue in photopolymerization? An example for the preparation of high content iron-containing opaque composites and application in 3D printing

Imidazole based dual photo/thermal initiators for highly efficient radical polymerization under air with a metal-free approach

Synergistic Approach of Type I Hybrid Complexes for highly efficient Metal-based Initiating Strategies: Toward low energy-consuming polymerization for Thermoplastic Composite Implementation