Ring-opening polymerization cyclic amine

Goethals, E. J., Cyclic Amines, Chap. 10 in Ring-Opening Polymerization, Vol. 2, K. J. Ivin and... 

Although the pKa or H0 values for several acids are known [10,11], the definition of strong acid is somewhat arbitrary, because the position of equilibrium (13) depends on the basicity of heterocyclic monomer. Because this basicity varies from rather low (e.g., cyclic acetals) to rather high (e.g., cyclic amines) no universal rule describing the behavior of particular protonic acids in ring-opening polymerization exists. 

The results show that the presence of bulky substituent on a polymer chain may effectively inhibit the termination proceeding by this mechanism. The results presented at this point may be summarized as follows chain transfer to polymer is a general feature of cationic ring-opening polymerization although for different systems the contribution of this reaction may vary only in some systems this process results in termination (These systems involve, e.g., cyclic amines (3- and 4-membered) and cyclic sulfides (3- and 4-membered) and the contribution of the reaction is reduced for substituted chains. 

The problem of water in ionic ring-opening polymerization is much less critical than in vinyl polymerization, because, if present, water in the former system has to compete with relatively nucleophilic monomer present in large excess. Thus, certain polymerizations (e.g., polymerization of cyclic amine-conidine) can be conducted even in alcohols as solvents. 

Onium Ions. Trialkyloxonium ions (R O A ) became the conventional initiators for the cationic ring-opening polymerization of all classes of heterocycles (cyclic acetals, ethers, sulfides, lactones, phosphates, and amines). They are prepared by two methods developed by Meerwin (38) and Olah (39). Another more general and convenient synthesis method was recently developed by Penczek et aL (40) ... 

Living cationic ring-opening polymerization (CROP) techniques represent important methods for the polymerization of a wide variety of heterocyclic monomers, such as cyclic ethers, cyclic amines, and cyclic imino ethers [7, 84-87]. The main differences between carbocationic polymerization of vinyl monomers and CROP of heterocyclic monomers arise from the nucleophilic heteroatoms... 

G.D. Jones, Chapt. 14 in The Chemistry of Cationic Polymerization (P.H. Plesch, ed.), Peigamon Press, Oxford, 1963 EJ. Goedials, Cyclic Amines, C ap. 10 in Ring-Opening Polymerizations, 1. 2 (KJ. Ivin and T. Saegusa, eds.), Elsevier, London, 1984. 

Murayama, M., Sanda, F., Endo, T., 1998. Anionic ring-opening polymerization of a cyclic carbonate having a norbomene stmcture with amine initiators. Macromolecules 31, 919-923. 

Problem 10.5 Like cyclic ethers, cyclic amines can be polymerized by ionic ring-opening method. Thus poly(ethyleneimine) can be prepared by the ring-opening polymerization of aziridine (see Table 10.1) with initiation by protonic acids followed by nucleophilic attack of the monomer. Account for the fact that the process gives rise to a branched polyamine and suggest a method by which the branching could be avoided to obtain a linear polyamine. 

The ring-opening polymerization of cyclic carbonates with polyfunctional amines forms poly (hydroxy 1-urethanes). The most traditional syntheses of cyclic carbonates use phosgene chemistry, which involves environmental hazard issues [100]. 

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