Fractionated crystallization incompatible polymer blends

The crystallization of the minor component in incompatible polymer blends starts sometimes at distinctly larger undercoolings than in the pure polymer, and proceeds in several separated steps. After a short survey on the history of the effect in the available literature, the several types and the origin of this "fractionated crystallization" as observed in some selected systems are described. The information on the blend which can be deduced from the effect is discussed, and the consequences for the blend processing and properties are investigated. 

This survey on the literature indicates that only few data are available on the droplet crystallization phenomena in incompatible polymer blends. Moreover, these observations are partly not completely explained, and, where explained, these explanations are partly not satisfying or contradictory. In the next chapter, therefore, experimental results for some selected systems as investigated by the authors are presented with the aim to show all faces and properties of fractionated crystallization in detail, and to contribute to a better understanding of the origin of the effect. 

Frensch H, Harnischfeger P, Jungnickel BJ. Fractionated crystallization in incompatible polymer blends. In Utracky L, Weiss R, editors. Multiphase Polymers Blends and lonomers. Toronto ACS Symp Series 395 1989. 

Erensch, H., Hamischfeger, E, Jungnickel, B.J. Fractionated crystallization in incompatible polymer blends. In Multiphase Polymers, Blends, lonomers and Interpenetrating Networks, Utracki, L.A., Weiss, R.A., eds. ACS Symp. Series 395. Washingthon, DC, 1989. 

---