One‐component, double‐chromophoric thioxanthone photoinitiators for free radical polymerization

Abstract

Two one‐component, double‐chromophoric thioxanthone photoinitiators, namely TX‐EDA and TX‐DETA were synthesized by the reaction of thioxanthone aldehyde (TX‐A) with ethylenediamine (EDA) and diethylenetriamine (DETA), respectively via a facile Schiff base reaction. Both photoinitiators were characterized by spectral analysis and photobleaching studies. DFT calculations are employed to reveal the contribution of the different orbitals to the excitation of the initiators. The double‐chromophoric nature of the initiators gives rise to an increased absorption in the near UV region when compared with the pristine TX‐A. Photoinitiated polymerization of various vinyl monomers with TX‐EDA and TX‐DETA has been investigated in the presence and absence of a co‐initiator and compared for formulations consisting of precursor TX‐A. In addition, real‐time FTIR spectroscopic studies were performed in methyl methacrylate polymerization with both initiators. The higher efficiency observed with TX‐DETA may be attributed to the additional hydrogen donating sites adjacent to nitrogen atoms. © 2017 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2017, 55, 3475–3482

1-(2-Naphthyl)-2-(1-pyrrolidinyl)ethanone as a Photoinitiator for Methyl Methacrylate Polymerization

“…These initiators produce the initiating radicals by reacting with co-initiators like thiols, amines, ethers and alcohols. Type 1 initiators require high energy for bond cleavage and they need to use high-energy light sources that have short wavelengths [14][15][16][17].…”

Thioxanthone: a powerful photocatalyst for organic reactions

“…[50][51][52] Finally, there is also a third group of molecules that provide basically a combination of the two above discussed mechanisms, where intermolecular and intramolecular HAT can be performed by molecules 32 and 34 (scheme 9) to promote the propagation route or interaction with oxygen, like molecule 33 (Scheme 9), forming radical oxygen species that can abstract hydrogen from the monomers. [53][54][55] All the above three categories of photoinitiators were developed because the use of an external co-initiator can often lead to various undesired pathways.…”

Caesium for Perovskite Solar Cells: An Overview

“…[207] The modified PSCs exhibited reproducible PCE values with little hysteresis in the J-V curves, achieving efficiencies up to 19.5 and 20.6 %f or the Cs 2 CO 3modified and CsI-doped cells, respectively.T he dream for PSCs remains that of approaching as table and reproducible technology because it has also been important for DSSCs [208][209][210][211][212][213][214][215][216][217][218][219][220][221] and other energy-relatedd evices. [222][223][224][225][226][227][228][229][230][231] Caesium-Doped Perovskites in Emerging Technologies Enhanced optical absorption, long carrierd iffusion length and high carrierm obility of perovskite materials can also be exploitedi no ther applications than standard solar cells. Moreover,t he integration of PSCs with energy storages ystems [232][233][234][235][236][237][238][239][240] represent as trong research platform for future years.…”

“…The modified PSCs exhibited reproducible PCE values with little hysteresis in the J‐V curves, achieving efficiencies up to 19.5 and 20.6 % for the Cs 2 CO 3 ‐modified and CsI‐doped cells, respectively. The dream for PSCs remains that of approaching a stable and reproducible technology because it has also been important for DSSCs and other energy‐related devices …”