Methyl methacrylate group transfer polymerisation

Mixtures of photoinitiators have been actively studied. Michler s Ketone and benzoyl peroxide have been shown to effectively induce the photopolymerisation of methyl methacrylate through the formation of an initial complex shown in scheme 3 7, Although the exact initiating radical does not appear to be ascertained it is almost certainly the arylalkylamino radical from the Michler s Ketone. In the interaction of benzil and thioxanthone with triethylamine in the photoinduced polymerisation of acrylic monomers their is a competition between reverse electron transfer and ketyl radical formation . As the carbonyl concentration increases the bimolecular termination rates due to radical recombination increases. The same workers also studied the same system but replaced the ketone initiators with pyrene . Their inability to identify pyrene end groups indicated that the active initiating species arise from a complex between the pyrene and the triethylamine. 

The polymers were synthesised from boc-protected amine monomers and alkyl or benzyl methacrylate monomers. The polymerisation was performed by applying AIBN, as a radical initiator, and methyl 3-mercaptopropionate, as a chain transfer agent, in acetonitrile. The treatment of boc-protected polymers with TFA produced amphiphilic random copolymers with cationic ammoninm groups in the side chains. 

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