Irgacure photoinitiators

Irgacure Photoinitiators are products of the CIBA-GEIGY Corporation. 

The photoinitiator selected for this study was 1-benzoyl cyclohexanol (Irgacure 184 from Ciba Geigy), a compound known for its high initiation efficiency and the weak coloration of its photoproducts. The multifunctional monomer was an epoxy-diacrylate derivative of bis-phenol A (Ebecryl 605 from UCB). A reactive diluent, tripropyleneglycol diacrylate, had to be introduced in equal amounts, in order to lower the viscosity of the formulation to about 0.3 Pa.s. 

Photoinitiators. Photoinitiators used include Darocur 1173 and Darocur 4265 which are 2-hydroxy-2-methyl-1-phenyl-1-propanone Irgacure 907, which is 2-methyl-1-... 

Observations The commercial Norrish Type I photoinitiator Irgacure -819, bis(2,4,6-... 

A TNT explosive was determined in the gas phase using an MIP-QCM chemosensor [127]. The MIP preparation procedure involved dissolution of an appropriate amount of the TNT template, MAA monomer, EGDMA cross-linker and Irgacure 369 [2-benzyl-2-dimethylamino-l-(4-morpholinophenyl)-butanone-l] photoinitiator... 

In another report, transparent channels (of width 500-200 pm and depth 50-180 pm) were filled with a photopolymerizable liquid mixture consisting of acrylic acid and 2-hydroxyl methacrylate (1 4 molar ratio), ethylene glycol dimethacrylate (1 wt%), and a photoinitiator (3 wt% Irgacure 651 or 2,2-dimethoxy-2-phenylacetophenone). Polymerization was completed in less than 20 s to produce the hydrogel structures [221]. 

Processing of the crosslinkable materials (mixtures) starts with the same techniques as before and additional curing with UV irradiation at 90°C employing 1-2.5% photoinitiator (Irgacure 907). 

Onium salts are also reduced by photoinitiators such as hydroxy cyclohexyl phenyl ketone (IRGACURE 184), which efficiently form easily oxidizable free radicals as is shown in Figure 9. 

Viscosities were measured using a Brookfield viscometer with a Thermosel attachment. Stress-strain properties were determined on 3-10 mil films of the homopolymerized oligomer using an Instron Tensile Tester. The films were obtained from warm resin containing 4 pph photoinitiator, Irgacure 184. 

Materials. The photopolymerizable resin was made of 3 main compounds (i) a photoinitiator that generates free radicals upon exposure to UV radiation (ii) a prepolymer end-cap with acrylate groups (iii) a reactive acrylic diluent to lower the viscosity of the resin. For most experiments, the selected photoinitiator was a,a dimethoxyphenylacetqihenone, DMPA (Irgacure 651 from Qba-Geigy), because of its high initiation efficiency. 

The performance of a new photoinitiator, diphenoxybenzophenone (DPB), has been evaluated and compared to benzophenone (BZP) and Irgacure 651. DPB was synthetized by phosgenation at 9QPC of diphenyletiier in the presence of AICI3. A small amount of a tertiary amine, methyldiethanolamine (MDEA), had to be introduce in the formulation since, like for BZP, the radical production upon photolysis proceeds by hydrogen transfer from the donor molecule to the excited state of DPB. 

The rate constant for the propagation reaction was determined by the pulsed laser method.In order to avoid interference with the excitation of the monomer, a photoinitiator, which absorbs up to ca. 410 nm was selected, among others 2-benzyl-2-dimethylamino-l-(4-morpholinophenyl)bu-tanone-1 (Irgacure 369, Ciba). Using 2,2-dimethoxy-2-phenylacetophe-none as photoinitiator, the propagation rate constants were not accessible for temperatures exceeding 20°C. 

Figure 7. front propagating in a solution of 1,6 hexanediol diacrylate (40%) and DMSO (60%) with ultrafine silica gel, 6.7% w/v. Ammonium persulfate was the thermal initiator and Irgacure 184 the photoinitiator. Courtesy of... 

Novikova et al., reported that some pentaaza-1,4-dienes can photo initiate polymerization. Thus, l,5-Bis(4-methoxyphenyl)-3-methyl-l,4-pentazadiene, l,5-diphenyl-3-(2-hydroxyethyl)-l,4-pentaza-diene, and 1,5-diphenyl-3-methyl-l,4-pentazadiene were used as photoinitiators of radical polymerization of hexanediol diacrylate and of methyl methacrylate. Photoinitiation abilities of these compounds were compared with those of a commercial photoinitiator, Irgacure 1700. The pentaazodienes showed a high initiation capacity. Also, the activation energy of the polymerization in the presenee of the pentaazodiene compounds was lower than that for Irgacure 1700. 

Phenylglycine derivatives were found to act as co-synergists for the iron-arene complexes when used in conjunction with dyes and amines. It should be pointed out, however, that at this time the exact identity of the photo generated species that do the initiation is still uncertain. A commercially available photoinitiator of this type is Irgacure 261, (ri -2,4-cyclopentadienyl)-l,2,3,4,5,6--[(1-methyl ethyl)-benzene]ironhexafluorophosphate " ... 

Scott et a/., carried out Fourier transform infrared and electron spin resonance spectroscopic investigations of the photopolymerization of vinyl ester resins These consisted of studying reaction kinetics during photopolymerization of bis glycol methacrylate/styrene blends using commercial photoinitiators, Irgacure 819 and Lucirin TPO ... 

Glycidyl methacrylate was the basis of a photocomposition IRGACURE-651 was used as photoinitiator at different concentrations. 

IRGACURE 651 photoinitiator 2,2-dimethoxy-1,2-diphenyl ethane-l-on (photoinitiator)... 

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