Die steife amorphe Phase in teilkristallinen Polymeren
Rigid amorphous fraction in semi-crystalline polymers
Semi-crystalline, linear polymers contain crystalline and amorphous phases. These phases, usually, are interconnected by macromolecules. The molecules continue from the crystalline to the amorphous phase, are decoupled at the interface, but can transmit stress from one phase to the other. The thickness and the properties of the interface between crystals and surrounding amorphous structure are primarily controlled by the structure of the crystal surface, and the resulting conformational strain within the phase-crossing molecules. Molecule segments of the amorphous phase may be constraint/immobilized, due to the coupling of the crystalline and amorphous phases by covalent bonds.
At present, we study the effect of the specific surface area and surface fine-structure of crystals on the fraction of immobilized amorphous phase. In detail, we generate crystals of different size and perfection by variation of the pathway of crystallization, and monitor the rigid amorphous fraction by analysis of the glass transition using calorimetry. This research is considered as continuation of our former analysis of the surface-structure of polymer crystals in semi-crystalline preparations, using the degree-of-reversible-melting as a probe. Thus, we consider both reversible melting and existence of rigid amorphous fraction in semi-crystalline polymers, to be related to the linkage of crystalline and amorphous phases.
Selected publications
R. Androsch, B. Wunderlich
Analysis of the Degree of Reversibility of Crystallization and Melting in Poly(ethylene-co-1-octene)
Macromolecules 33, 9076-9089 (2000).
R. Androsch, B. Wunderlich
Specific Reversible Melting of Polymers
J. Polym. Sci., Polym. Phys. 41, 2039-2051 (2003).
R. Androsch, B. Wunderlich
The Link Between Rigid Amorphous Fraction and Crystal Perfection in Cold-Crystallized Poly(ethylene terephthalate)
Polymer 46, 12556-12566 (2005).
R. Androsch, H.-J. Radusch, S.S. Funari
Crystallization, Glass Transition and Morphology of (R)-3-hydroxybutyrate Oligomers
European Polymer Journal 43, 4961-4974 (2007).
