Poly methyl methacrylate as Template

Many radical polymerization systems were examined hy Challa at a/. A number of papers were devoted to polymerization of methyl methacrylate, MM, in the presence of poly(methyl methacrylate). The role of tacticity of template was stressed. Isotactic PMM forms stereocomplex with syndiotactic PMM. Polymerizations of MM in the presence of isotactic PMM were carried out and the product (template + daughter polymer) was analyzed by NMR. When MM is polymerized in the polar solvent in the presence 

Polymerization of MM in the presence of syndiotactic PMM was also reported. In this case, PMM of mostly isotactic structure was produced. Interaction between growing chains and the template is rather weak. The template influence is not as pronounced as in the case of isotactic template. Matsuzaki at al used deuterated syndiotactic PMM as template for polymerization of MM. The measurements of tacticity by NMR were 

According to Tan and Challa, this result is caused by a template with too low a molecular weight and the influence of deuterium substitution. Critical length (minimum number of units necessary for template effect), estimated for isotactic PMM at 10-20 monomer units, is roughly 600 in the case of high molecular syndiotactic PMM. 

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