“Mono” and “bifunctional” aromatic esterificated benzophenone photoinitiators for free radical polymerization

Abstract

Aromatic esterificated benzophenone derivatives, benzoic acid 4-benzoyl-phenyl ester (BPBz) and bis-benzoic acid 4-benzoyl-phenyl ester (BisBPBz) were simply synthesized and characterized. The triplet states of the photoinitiators were determined by laser flash photolysis and phosphorescence spectroscopy. The photodecomposition of the initiators was performed by UV light; the increase in the absorption spectra was attributed to the decreasing number of ester groups which led to an increase in ketone groups according to the Photo-Fries rearrangement of aromatic esters. The photoinitiation capabilities for methyl methacrylate (MMA) polymerizations were investigated under air and nitrogen atmospheres. Esterfunctional benzophenone photoinitiators were found to be more effective than benzophenone (BP) in the presence of a co-initiator for photoinduced free radical polymerization of MMA. The kinetics of photopolymerization for different formulations which consist of multifunctional acrylates was also studied using the Real-Time Fourier Transform infrared spectroscopy (RT-FTIR) method. The film properties of these formulations were investigated after curing of films by Mini-UVCure equipment.

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

“…Polymerization reactions are extensively performed in various commercial areas such as coatings, 3D curing, imaging materials, photoresists, halographic recordings and nanoscale micromechanics [1][2][3][4][5][6]. The development of the photocuring industry depends on improvement of photoinitiating systems that have the standards required for industrial fabrication.…”

Benzophenone derivatives as novel organosoluble visible light Type II photoinitiators for UV and LED photoinitiating systems

“…On the other hand, the ketyl radical is relatively stable. [22,23] Although, the BP has utilized for FRP in the past decades. There are still some disadvantages and limit the application of BP based photoinitiator package in stateof-the-art FRP applications.…”

Naphthoylenebenzimidazolone dyes as one‐component photoinitiators

“…In the last decade many papers have described the synthesis of initiators. Only thioxanthone [3][4][5][6][7][8][9], benzophenone [10][11][12][13][14][15][16], erythrosine B [17], and, more recently, naphthoquinone [18] and benz[cd]indol-2(1H)-one [19] linked with appropriate groups have been applied as chromophores to obtain one-component initiator systems. There are two different ways to create initiators sensitive to visible radiation.…”

“…Such initiators are both photosensitiser and coinitiator, and their excited state is responsible for the generation of initiating radicals (Scheme 2). Only thioxanthone [3][4][5][6][7][8][9], benzophenone [10][11][12][13][14][15][16], erythrosine B [17], and, more recently, naphthoquinone [18] and benz[cd]indol-2(1H)-one [19] linked with appropriate groups have been applied as chromophores to obtain one-component initiator systems.…”