Thermal properties, polymeric materials overview

In this chapter an overview of conceptually different fracture theories is presented which have in common that they do not make explicite reference to the characteristic properties of the molecular chains, their configurational and super-molecular order and their thermal and mechanical interaction. This will be seen to apply to the classical failure criteria and general continuum mechanical models. Rate process fracture theories take into consideration the viscoelastic behavior of polymeric materials but do not derive their fracture criteria from detailed morphological analysis. These basic theories are invaluable, however, to elucidate statistical, non-morphological, or continuum mechanical aspects of the fracture process. 

This chapter is devoted to the properties of polymeric gel-forming liquids. Particulate gels are discussed in Chapter 7. The structure of a polymeric gel is sketched in Fig. 5-1. Since this book is devoted to materials that are in some sense liquid, or at least liquefiable, we shall not say much about hard, irreversible, chemical gels such as cured epoxies or vulcanized rubber, but shall focus instead on chemical pre-gels and thermally reversible physical gels, both of which can be considered borderline fluids. This chapter is confined to a brief overview. Much more detail can be found in Winter and Mours (1997), and volume 101 of the Faraday Discussions. ... 

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