Macromolecular photoinitiators

Chart 10.2 Chemical structures of photosensitive moieties contained in typical macromolecular photoinitiators. 

Some of the most important benefits connected with the macromolecular architecture of polymeric photoinitiators can be summarized as follows. 

PCMS) 1 8 mol/mol mixture has also been checked (Table 16). Indeed, the above mixture is found to show a slightly lower activity with respect to PABOK, thus suggesting that polymeric photoinitiators based on photosensitive moieties undergoing homolytic fragmentation may also display an activity synergism, provided that different photoreactive groups are anchored to the same macromolecular chain. 

Case Study 6.38 Macromolecular chemistry - photoinitiated polymerization of methacrylate... 

Diaryliodonium salts are industrially employed as photoinitiators in cationic polymerizations [8-10]. They have been employed as Lewis acids [11], as oxidants (via formation of phenyl radicals) [12, 13], and in the area of macromolecular chemistry [14, 15]. Furthermore, diaryliodonium salts show biological activity in various applications, usually because of their ability to act as radical initiators [3, 16]. Diphenyleneiodonium chloride (DPI) is a cyclic diaryliodonium salt which has found numerous biological applications, often as a NADPH oxidase inhibitor ([17] see also [20 0] in [18]). The applications outlined above do not involve arylations and are hence not covered in this chapter. 

CRI 01] Crivello J.V., Hua Y., Gomurashvili Z., Monomeric and polymeric carbazole photosensitizers for photoinitiated cationic polymerization , Macromolecular Chemistry and Physics, vol. 202, pp. 2133-2141, 2001. 

YAG 94] Yagci Y., Schnabel W., Direct and sensitized photoinitiated cationic polymerization using pyridinium salts , Macromolecular Symposia, vol. 85, no. l,pp. 115-127, 1994. 

KAH 08a] Kahveci M.U., Tasdelen M.A., Cook W.D. et al, Photoinitiated cationic polymerization of mono and diviityl ethers in aqueous medium using ytterbium triflate as lewis acid , Macromolecular Chemistry and Physics, vol. 209, pp. 1881-1886,2008. 

TAS 06a] Tasdelen M.A., Kiskan B., Yagci Y., Photoinitiated free radical polymerization using benzoxazines as hydrogen donors , Macromolecular Rapid Communications, vol. 27, pp. 1539-1544,2006. 

YAG 92b] YaGci Y., Schnabel W., New aspects on the photoinitiated free radical promoted cationic polymerization , Makromolekulare Chemie, Macromolecular Symposia, vol. 60, pp. 133-143,1992. 

Very active is the area of macromolecular chemistiy, with applications that range from new photoinitiators to new polymerization mechanisms (RAFT, reversible addition-fragmentation), useful for obtaining advanced microparticle design. ... 

In particular, above said may be applied also to photoinitiated radical (co)polymerization of mono- and polyfimctional monomers. Two diamet-rically-opposite concepts are used to deseribe the kinetics of photoinitiated (co)polymeiization. The first one is the concept of diffusion-controlled reactions, based on the assumption about the diffusion control of elementary acts of macromolecular chain propagation and decay [14]. The second concept is the radieal polymerization model, based on the notion of mi-... 

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