Ring-opening polymerization of heterocyclic monomers

Here is an example of the polymerization of epoxides To a CH2CI2 solution of Ic (1 mmol) under dry nitrogen are added 400 equivalents of epoxyethane (11, R=H) at room temperature ([lc]o = 16.7 mM), whereupon the polymerization immediately starts with heat evolution and is 

This means that every molecule of Ic produces one polymer molecule, a phenomenon typical of living polymerization. Likewise, Ic can also bring about living polymerization of substituted epoxides such as 1,2-epoxypropane (11. R = Me) and 1,2-epoxy butane (11, R = Et) to give polyethers with narrow MWD.-  

Although alkali metal alcoholates are known to initiate living anionic polymerization of epoxyethane (11, R = H), use of these conventional initiators for the polymerization of substituted epoxides results in the concomitant occurrence of side reactions with respect to the substituents.- With 11 (R = Me) as a monomer, a proton transfer from the methyl group of 11 (R = Me) to the growing alcoholate species occurs, to give a polymer having a hydroxyl ter- 

By virtue of the clear initiation mechanism, well-dehned end-functionaUzed polyethers can be synthesized. For example, use of an aluminum porphyrin having a 4-vinylphenolate ligand at the axial position as initiator for the polymerization of 1,2-epoxypropane (11, R = Me) allows formation of a tailored polyether with a polymerizable (styryl) end group (27).  

In relation to the polymerization of epoxides. Amass et al. have reported that Ic, at a high temperature such as 60 C, can also bring about anionic polymerization of 

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Pencek, S., Kubisa, P. and Matyjaszewski, K. Cationic Ring-Opening Polymerization of Heterocyclic Monomers. Vol. 37, pp. 1 —149. 

Penczek S, Cypryk M, Duda A, Kubisa P, Slomkowski S (2007) Living ring-opening polymerizations of heterocyclic monomers. Prog Polym Sci 32 247-282... 

Living Ring-Opening Polymerization of Heterocyclic Monomers with Aluminum Porphyrin-Organoaluminum Compound Systems... 

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