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Abstract: The perfection, reorganization, and isotropization of the mesophase of isotactic polypropylene were investigated by fast scanning calorimetry (FSC). The analysis was made at different heating rates, to evaluate the isotropization temperature of the initially grown mesophase and of mesophase which has been perfected or even reorganized into crystals. Mesophase formation is paralleled by formation of a rigid–amorphous fraction which was about twice the mesophase content. While the isotropization temperature of the initially grown mesophase is controlled by the temperature of its formation, the isotropization temperature of perfected or reorganized mesophase was independent on the condition of prior formation. Absence of exothermic heat flow during heating suggests that the mesophase converted gradually into crystals due to the fast heating rate. The discussion of data includes new ideas about nucleation, growth, and perfection of the mesophase, involving nanophase to microphase and rigid–amorphous fraction to mesophase transitions. [Copyright &y& Elsevier]

Abstract: A number of discussion points are raised concerning the nonequilibrium melting and crystallization as described in the paper by Sommer and Reiter.1 [Copyright &y& Elsevier]

Abstract: The influence of the surface on the thermodynamics of the melting and glass transition of films and fibers is negligible as long as the dimension of the phase is macroscopic, i.e., is more than 1μm in all directions. The influence of the surface on microphases was discovered at the beginning of the 20th century, and is presently developing into the central topic for the description of hard and soft nanophase materials. The central issues of the thermal analysis of films and fibers, thus, are: the assessment of small sample masses, the evaluation of the nature of the surface, the treatment of irreversible phase structures, and the use of fast measurements to avoid reorganization of the metastable material without loss of precision. A short history of the roots of calorimetry of such small systems is used to arrive at a thermodynamic description of linear macromolecules in the amorphous state and, when partially crystallized, in the macroscopic, globally metastable structure which consists of multiple nanophases. [Copyright &y& Elsevier]

Linear, flexible macromolecules are long recognized as phase structures limited to micrometer and nanometer dimensions with covalent bonds crossing the interfaces. This special, usually non-equilibrium structure leads to unique properties and a multitude of changes for different thermal and mechanical histories. Analyses that enable the study of these properties are temperature-modulated calorimetry and related techniques which allow the separation of equilibrium and non-equilibrium responses. Research on these topics is reviewed and combined to a model for the nanophases. The new approach to the complex nanophase systems yields a better understanding of the relationship between structure and thermodynamic properties. Special emphasis is placed on the size and surface effects on the glass and melting transitions, the development of rigid-amorphous phases, and the reversible melting within the globally metastable structure. [Copyright &y& Elsevier]