Thermotropic polymers comb-shaped

Another key direction in the field of mesophase polymers is the synthesis and study of functional thermotropic LC systems based on side-chain (comb-shaped) macromolecules containing long aliphatic branching —(CH2)n—CH3 (n = 4-21) in each main-chain monomer unit (Figure 9). 

Subsequently, this approach was verified and developed in numerous works performed in many laboratories across the world and has became a commonly accepted method for S)mth-esis of thermotropic LC polymers with side mesogenic groups, or comb-shaped LC polymers. " ... 

The study of the molecular organization of lyotropic and some thermotropic comb-shaped polymers was of primary importance in understanding the mechanism of formation of intramolecular orientational order [9] these concepts subsequently served as the basis for notions on ordering of liquid-crystal polymers on the molecular level. 

The possibility of synthesizing a large number of comb-shaped thermotropic polymers with a different structure of the main chain [31-35], different mesogenic fragments [36-41], and a different type of connection to the main chain provides broad opportunities for their investigation [1, 2, 19, 31, 43-50]. The presence of chemical groups which cause the formation of the liquid-crystalline phase in their side chains, while the main chain of the molecule can be flexible, is a basic structural feature of these comb-sh )ed mesogenic macromolecules. 

It follows from the data in Table 3.2 and Fig. 3.3 that the rigidity of the main chain increases with an increase in the length of the side chains for both the previously studied comb-shaped macromolecules and for the macromolecules of thermotropic polymers with mesogenic fragments in the side chains. The ob-... 

The high intramolecular ordering of the thermotropic mesogenic polymer is also reflected in the strong effect of the solvent on the size of the molecules—the value of the intrinsic viscosity [ti]— in different solvents with presCTvation of the molecular weight of the sample [58]. The intrinsic viscosities [t ] (at 21 C) of mesogenic comb-shaped polymers of the polymethacrylate series in different solvents are reported below ... 

Soviet specialists have made a basic contribution to the creation and evolution of Ais field, particularly in the study of lyotropic systems as the basis for high-strength fibers and the first thermotropic liquid-crystal polymers which were created from comb-shaped macromolecules. 

Prior to discussing LC elastomers, we will consider in Sect. 2 in some detail the conformations and chain anisotropy of their polymer counterparts because the polymer backbone generates the shape anisotropy and elastic response of the elastomer network. In this context, note that two different classes of thermotropic LC polymers exist main-chain and side-chain (comb-like), as depicted in Fig. 1). In side-chain LC polymers, the pendant mesogenic groups are linked to a linear polymer backbone... 

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