In the last two chapters of the book on Thermal Analysis of Polymeric Materials the link between microscopic and macroscopic description of macromolecules will be discussed with a number of examples based on the thermal analysis techniques which are described in the prior chapters. Chapter 6 deals with single-component systems, Chap. 7 with multiple-component systems. It is shown in Sect. 6.2, as suggested throughout the book, that practically all partially crystalline polymers represent nonequilibrium systems, and that thermodynamics can establish the equilibrium limits for the description. It was found, however, more recently, that equilibrium thermodynamics may be applied to local areas, often small enough to be called nanophases ^[1]. These local subsystems are arrested and cannot establish global equilibrium.

Amorphous polymers are easier to treat as equilibrium systems as long as they consist of single components above their glass transition temperature and are without extensive surface that introduce significant local stresses, as shown in Sect. 6.3. For macromolecules, in general, the meaning of the term component was relaxed to account for the fact that macromolecules are sufficiently large, so that small changes in their length do not affect their properties significantly, i.e., all macromolecules in a distribution are considered to be one component. Note, that this is not true for distributions that contain oligomers, defined in Sect. 3.1 as molecules below 1,000 atoms in size. Similarly, decoupled segments of a polymer chain may change the accounting for components, as is shown in Sect. 6.2. Section 6.1 is a review...