Macro molecular chain, configuration

P. J. Flory Spatial configuration of macro molecular chains, The 1974 Nobel Lecture, Brit. Polymer J. 8, 1-10 (1976). 

So, it is seen that stereoisomers are considered differently in macro-molecular chemistry to what they are in low-molar-mass chemistry. In macromolecular chemistry, one begins at one end of the main chain and considers the configuration of each main chain atom relative to the preceding... 

The X-ray diffraction pattern of low molecular paraffin crystals shows interesting changes when the temperature is raised, indicating that, before the melting point is reached, the lateral spacings of the chains become less differentiated and it is assumed that the chains then become free to rotate around their long axes. In macro-molecular hydrocarbons the crystallites disappear beyond a certain temperature and the chains then coil up to form randomly kinked configurations. This is accompanied by the contraction of the macroscopic object if it was initially anisotropic. 

In view of the presence of the free volume Vf, the macro-molecular polymeric chains still retain a certain degree of freedom of motion that allows for some configurational changes under loads. These changes may be viewed as occurring against viscous resistance and are therefore time dependent. 

Polymer products synthesized in laboratories and in industry represent a set of individual chemical compounds whose number is practically infinite. Macro-molecules of such products can differ in their degree of polymerization, tactici-ty, number of branchings and the lengths that connect their polymer chains, as well as in other characteristics which describe the configuration of the macromolecule. In the case of copolymers their macromolecules are known to also vary in composition and the character of the alternation of monomeric units of different types. As a rule, it is impossible to provide an exhaustive quantitative description of such a polymer system, i.e. to indicate concentrations of all individual compounds with a particular chemical (primary) structure. However, for many practical purposes it is often enough to define a polymer specimen only in terms of partial distributions of molecules for some of their main characteristics (such as, for instance, molecular weight or composition) avoiding completely a... 

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