Morphological Structure, and Melting of Polymer Blends

CRYSTALLIZATION, MORPHOLOGICAL STRUCTURE, AND MELTING OF POLYMER BLENDS 

When the melt of a crystalline polymer is cooled to a temperature between the glass-transition and the equilibrium melting point, the thermodynamic requirement for crystallization is fulfilled. 

Eor the discussion of the crystallization and melting behavior in immiscible polymer blends, a division into 3 main classes is proposed. 

A completely different behavior is reported for blends in which the crystallizable phase is dispersed. Fractionated crystallization of the dispersed droplets, associated with different degrees of undercooling and types of nuclei is the rule. The most important reason is a lack of primary heterogeneous nuclei within each crystallizable droplet. An important consequence of fractionated crystallization may be a drastic reduction in the degree of crystallinity. 

When two crystallizable components are blended, a more complex behavior due to the influence of both phases on each other is expected. In general, the discussion for matrix crystallization and droplet crystallization can be combined. However, crystallization of one of the phases can sometimes directly induce crystallization in the second phase. As a consequence, the discussion of blends of this type has been subdivided with respect to the physical state of the second phase during crystallization. The special case of coincident crystallization , in which the two phases crystallize at the same time, is discussed. Finally, the effect of compatibilization of crystalline/crystalline polymer blends is briefly reviewed. 

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Crystallization, Morphological Structure, and Melting of Polymer Blends... 

This chapter, related to the crystallization, morphological structure and melting of polymer blends has been divided into two main parts. The first part (section 3.1) deals with the crystallization kinetics, semicrystalline morphology and melting behavior of miscible polymer blends. The crystallization, morphological strucmre and melting properties of immiscible polymer blends are described in the second part of this chapter (section 3.4). 

G. Groeninckx, M. Vanneste and V. Everaert Crystallization, Morphological Structure and Melting of Polymer Blends , in Polymer Blends Handbook, L.A. Utracki, Ed., Kluwer Academic Publishers, Dordrecht, The Netherlands (in press). 

Groeninckx G, Vanneste M, Everaert V. Crystallization, morphological structure and melting of polymer blends. In Utracki LA, editor. Polymer blends handbook, vol. 1. Dordrecht Kluwer Academic Publishers 2002. p. 203-94 [chapter 3],... 

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