Photoactivated copolymerization

The free-radical reaction may be equally initiated by photoactivated sulfur dioxide (3S02)442 (equation 79). On the other hand, polysulfones are obtained by radical copolymerization of appropriate olefins with sulfur dioxide443-449, and similarly, uptake of sulfur dioxide by a radical-pair formed by nitrogen extrusion from an azo compound yields the corresponding sulfone450 (equation 80). Correspondingly, alkylbenzenes, dibenzoyl peroxide, and sulfur dioxide yield sulfones under thermal conditions451... 

Photoactivated Copolymerization. Although polymerization and copolymerization generally involve the addition of a monomer to a reactive chain end, the ground state charge transfer complex generated by the interaction of an electron donor monomer and a strong electron acceptor monomer, acts as a single unit and, upon excitation of the complex, both monomers enter the chain. 

As shown in Table II, the photoactivated copolymerization of styrene and methyl methacrylate in the presence of AlEt yields equimolar, alternating copolymers when the initial monomer charge contains excess styrene. However, when the comonomers are present in equimolar ratio, the copolymer is rich in methyl methacrylate. ... 

Table VI. Photoactivated Copolymerization of Butadiene and Acrylonitrile in Presence of AlCl and EtAlCl ...

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