Polymer compounds main chain structure

Diacetylene compounds with two nonconjugated acetylene groups, especially ol,oj-diynes may undergo various types of polymerization to provide polymers with different main chain structures. 

Strictly speaking, the term polyester ought to refer to a chemical compound containing many ester groups in each molecule. In practice, however, it usually refers to polymeric materials containing ester groups as major structural components of the main chains of the macromolecules of which the polymer is composed, and this is the sense in which it is used here. The term is not now usually applied to polymers that contain ester groups attached to the main chain either directly, as in cellulose triacetate, poly(vinyl acetate) or poly(methyl acrylate), or within short side-chains. 

The polymers can be oxidized by differential pulse polarography. Their oxidation is metal-centered and leads to Ru(III) compounds. The potential is located aroimd -1-1.26 V (SCE). It can be stated that the polymers which contain the triphenylamine structure imits in the main chain show, as expected, an additional peak caused by the amine nitrogen. Substitution at the triphenylamine by electron-donating substituents lowers these potentials to 1.05 V (25), whereas acceptor substituents cause an increase of the oxidation potential (23). 

Grafted Polymers. Due to the special chain structure ABS terpoly-mers have been widely modified by grafting vinyl monomers onto the main chain. We emphasize that the method how ABS itself is obtained is addressed sometimes as grafting styrene and acrylonitrile onto a butadiene rubber. Here we focus on grafting reactions on the ABS itself. Some examples of ABS grafted polymers are shown in Table 8.7. The pending acid functionalities may be allowed to react with amines and other compounds (45). 

In contrast to these lyotropic mesogenic materials, which require the presence of a solvent in order to produce a mesophase, thermotropic mesogens are those compounds which exhibit a mesophase in the melt state at temperatures above the crystalline solid state and before the formation of an isotropic melt Mesophase-forming polymers may possess either one of the two basic structures shown in Fig. 1 the polymer may either contain the mesogenic group (the part of the polymer molecule which is responsible for liquid crystallinity) directly in the main chain, or the mesogen may be present as a pendant group in the side chain. 

The reaction of optically active, helicene derivative 121 first with o-phenylenediamine and then with Ni(OAc)2 led to a helical polymer (Mn 7000) (122) having a unique ladder-type structure with Schiff base moieties immersed in the main chain (Figure 15) 206 -phg polymer showed red-shifted absorptions with respect to nickel salophene, the parent compound for the polymer, supporting the formation of a long conjugation system. Intense CD bands were reported for the polymer. 

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