Template polymerization discussion

Further discussion on the effects of the reaction media and Lewis acids on lacticily appears in Section 7.2. Attempts to control laciicily by template polymerization and by enzyme mediated polymerization are described in Section 7.3. Devising effective means for achieving stereochemical control over propagation in radical polymerization remains an important challenge in the field. 

The reaction of adenosine 5 -phosphoric imidazolide with adenosine analogues on a polyuridylic acid template is discussed in reference [158]. Another polymerization of oligoadenylates (pA)4 and (pA)6 on a polyuridylic acid template in an aqueous system... 

In the case of template processes, this mechanism must be completed by terms accounting for interaction between template, monomer, and polymer. This subject is discussed in more detail in Chapter 8. Intermolecular forces lead to absorption of the monomer on the template or, if interaction between monomer and template is too weak, oligoradicals form complexes with the template. Taking into account these differences in interaction, this case of template polymerization can be divided into two types. In Type I, monomer is preadsorbed by, or complexed with, template macromolecules. Initiation, propagation and perhaps mostly termination take place on the template. The mechanism can be represented by the scheme given in Figure 2.7. 

As discussed in Chapter 5, copolymers with unconventional distribution of units can be obtained by copolymerization in the presence of proper template. Synthesis of polymers with defined tacticity can be realized by template polymerization or copolymerization. In spite of the fact that many interesting potential applications seems to be possible neither template polymerization as a method of synthesis nor the products obtained in this process have been applied on an industrial scale until now. 

When beads are synthesized by polymerization from a homogeneous mixture, a pre-polymerization mixture, composed of functional monomer(s), cross-linker(s), initiator and template dissolved in a solvent, is prepared. This procedure is similar to that of bulk polymerization discussed above. The pre-polymerization mixture is, however, in this case further diluted with solvent so that polymer beads are formed rather than a monolithic polymer. In a sense, it seems more logical to use the term polymerization medium rather than porogen when referring to the solvent in a homogeneous polymerization. 

The most artides published in sdentific journals, many reviews, and chapters of encydopedias deal with template polymerization proceeding at least part of its lifetime in a one-phase system. In this chapter, the term matrix or template polymerization will be used mainly to refer to one-phase systems. Only at the end of this chapter will some examples of polymerization proceeding in a confined space be discussed. 

A specific class of template polymerization is connerted with polymerization of monomers included into cydodextrin (CD). This type of polymerization leads in between dassical template polymerization and polymerization in confined space, which will be discussed at the end of this chapter. From the other side, this type of polymerization is similar to polymerization of multimonomers described previously. 

Copolymerization of acrylamide with MAA in the presence of poly(alkylammonium chloride) as a template was described by Liu and co-workers. Microstructure of copolymer obtained by template polymerization, containing also phenoxy acrylate, was examined by NMR spectroscopy. Copolymerization was carried out in aqueous solutions with different pH. Dependence of hydrogen bonds between acrylamide blocks and MAA blocks on pH value of the solution was discussed in detail. 

It was shown that the template can influence the kinetic, molecular weight, molecular weight distribution, and chemical stmcture of the polymer formed. Special types of products obtained in template polymerization such as interpolymer complexes, ladder-type polymers, and copolymers seem to be interesting materials. Potential applications of such materials have been discussed. Polymerization processes dealing with most general understandings of the term template, particularly dealing with polymerization in confined space were also discussed. 

Mathematical description of the polymerization of biological macromolecules on templates, based on simple models, has been published by Simhaet al Two types of reaction were discussed. The first type of reaction was initiated by polymerization of two monomers on each template. The reaction proceeded throughout the addition of monomer to the growing ends or by the coupling of the growing chains. In the second type of re-... 

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