Monomers ionic type

Table 4-7= Copolymerization parameters of Sn(IV)-containing ionic-type monomers. 

Salts of unsaturated carboxylic acids such as acrylates or methacrylates are most important among the ionic-type monomers. As a general method of synthesis, the reaction of (hydro)oxides, (hydro)carbonates of metals as well as their alkyl(aryl) derivatives with unsaturated carboxylic acids is carried out [4]. Co(II), Ni(II), Zn(II) and Cu(II) acrylates exhibit the diacrylate structure 36 with one or two additionally coordinated solvent molecules such as water [182,183]. 

Ionic polymerizations are remarkable in the variety of polymer steric structures that are produced by variation of the solvent or the counter ion. The long lived nature of the active chain ends in the anionic polymerization of diene and styrene type monomers lends itself to studies of their structure and properties which might have relevance to the structure of the polymer produced when these chain ends add further monomer. One of the tools that, may be used in the characterization of these ion pairs is the NMR spectrometer. However, it should always be appreciated that, the conditions in the NMR tube are frequently far removed from those in the actual polymerization. Furthermore NMR observes the equilibrium form on a long time scale, and this is not necessarily that form present at the moment of polymerization. 

Nitroxides have been used to prepare numerous block copolymers. Initially, using the TEMPO moiety, only styrene-based monomers could be incorporated into copolymers, but with the use of new nitroxides like DEPN and BPPN, the list has expanded to include acrylate-type monomers, as well as dienes, something that previously could only be accomplished through ionic mechanisms. Unfortunately, chain extension of either St or diene-based macroinitiator with an acry-... 

From our point of view [8], the most effective classification is based on the type of bond between the metal and the organic part of the monomer molecule. On this principle, MCMs can be classed into the following major types monomers with a covalent, ionic, donor-acceptor, chelate and Ji-bound metal (Fig. 4-1). 

Copolymerization of ionic-type MCMs, alkali and alkaline earth metal salts, with various comonomers has been studied quite well. A detailed review of the basic studies has been given in a monograph [4] and they will not be analyzed in this book. Studies of the mechanism of copolymerization of such types of MCM were carried out in the case of organotin and -lead monomers. The widest recognition among these MCMs used as comonomers has been gained by trimethyl-, tributyl-, and triphenyltin methacrylates (Table 4-7) [4 and references therein]. 

Metal complexes bound to a polymer support most frequently induce ionic polymerization of olefins, dienes and acetylenes, and less commonly radical polymerization of vinyl-type monomers, acting at all reaction stages initiation, chain propagation and termination. Active sites for the addition of monomer molecules to the growing polymer chain can in many cases be regenerated yielding new polymer chains (catalysis via a polymer chain). 

Proteins are heteropolymers, and therefore application of the simple analysis given above for mixing homopolymers with diblock copolymers would seem to be a stretch for proteins. Yet, one of the simplest models for proteins divides the twenty natural amino acids into twocate-gories hydrophobic (H) and ionic/polar (P). The attraction between H-typ>e monomers models the tendency of hydrophobic polymers in water to collapse in order to minimize their exposed surface area, but also to minimize their interactions with P-type monomers. The minimiza-... 

In the OZO polymerization, depending upon the counteranion, the covalent-type species by X = I showed a reduced fep (about one-hundredth) compared with the ionic-type species by TsO , because the propagation is a dipole (covalent-type species)-dipole (monomer) reaction, formation of an oxazoli-nium ion is a rate-determining step (Scheme 6). 

Muldoon MJ, Gordon CM (2004) Synthesis of gel-type polymer beads fiom ionic liquid monomers. J Polym Sci A Polym Chem 42 3865-3869... 

Mixed pentahalides are more readily isolated and are of at least three types ionic, tetrameric, and less stable molecular trigonal-bipyramidal monomers. Thus, chlorination of a mixture of ASF3/ASCI3 with CI2, or fluor-ination of AsCU with CIF3 (p. 828) gives [AsCl4]" [AsF6] [mp 130°(d)] whose X-ray... 

The thermal (or photochemical) decomposition of the azo group gives rise to a radically initiated polymerization. The reactive site F, the transformation site, however, can, depending on its chemical nature, initiate a condensation or addition type reaction. It can also start radical or ionic polymerizations. F may also terminate a polymerization or even enable the azo initiator to act as a monomer in chain polymerizations. 

Furthermore, the reaction scheme implies that the molecular weight distribution is Poisson-like — i.e. very narrow — as it had been shown earlier on theoretical basis by Flory 8), Gold 9), and Szwarc l0>. Even though two (or more) types of active species add monomer at very different rates, the polydispersity remains narrow, provided solvation/desolvation and ionic dissociation/association processes are fast U). 

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