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Photoinitiator benzil ketals

The chromophore in this type of photoinitiator is frequently an aromatic carbonyl. The benzoyl radical is the major initiating species, while the other fragment may also contribute to the initiation, in some cases. The most efficient type I initiators are benzoin ether derivatives, benzil ketals, hydroxyl-alkylphenones, a-aminoketones, and acylphosphine oxides. Substituents on the aromatic carbonyl influence the absorption. [Pg.67]

II), benzil (III), and benzil ketals (IV). These and related compounds are extensively used as photoinitiators in commercial practice, usually in combination with hydrogen donors. [Pg.465]

Photoinitiation System. In most cases the curing is initiated by free radicals generated by UV light and photoinitiators. The free radicals can be formed from photocleavage or hydrogen abstraction mechanisms. Benzoin ethers, benzil ketals, and acetophenone derivatives are typical photoinitia,tors. [Pg.368]

Table 2.3. Some Benzil Ketals and Acetophenone Based Photoinitiators ... Table 2.3. Some Benzil Ketals and Acetophenone Based Photoinitiators ...
Those that undergo intramolecular bond cleavage, known as homo-lytic fragmentation type or Type 1 photoinitiators (a-cleavage type). Examples are benzoin ethers, substituted acetophenone derivatives, acyloxime esters, benzil ketals, and cyclic benzoin and benzils. Representative examples are shown in Figure 5.15. [Pg.266]

In a second study we have compared the performance of three commercial photolnltlators for surface cure in a commercial urethane acrylate formulation. The following photoinitiators were utilized in this study HCPK - alpha-hydroxy-alpha-cyclohexylphenylketone (Structure II), BDMK - benzil-dimethyl-ketal (Structure III), and AAP (Structure IV). The extinction spectra of these initiators are in Figure 8. [Pg.37]

Chem. Descrip. Benzil dimethyl ketal CAS 2465042-8 EINECS/ELINCS 246-386-6 Uses Photoinitiator for photopolymerization of polyester and acrylate UV-curable systems, adhesives, printing inks, surf, mount applies., photoresists, clear coatings on plastic/metal, and fillers/topcoats tor wood coatings... [Pg.111]

Benzil dialkyl ketals are also very efficient photoinitiators. They too are believed to decompose by the Norrish Type I cleavage ... [Pg.447]

In a typical procedure for photochemical, radical thiol-ene and thiol-yne reactions (Yu et al., 2009), a mixture of PNIPAm-S-ALMA or PNIPAm-S-PROPA (0.2 g), 100% excess of target thiol (based on the molarity of ene or yne ), benzil dimethyl ketal (Irganure 651) photoinitiator (15.0 mg) in an appropriate volume of THF is exposed to UV light (A = 350 nm) for 2 h. The sample is dialyzed against methanol. It should be noted that the thiol-ene and thiol-yne reactions yield mono and bis end-functionalized PNIPAm homopolymers, respectively (see Scheme P12.15.1). [Pg.714]


See other pages where Photoinitiator benzil ketals is mentioned: [Pg.61]    [Pg.213]    [Pg.101]    [Pg.312]    [Pg.172]    [Pg.30]    [Pg.180]    [Pg.505]    [Pg.1387]    [Pg.924]   
See also in sourсe #XX -- [ Pg.213 ]




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