Crystalline plasticity in isotactic polypropylene below and above the glass transition
temperature
G. Polt, F. Spieckermann, H. Wilhelm, Ch. Fischer, E. Schafler, S. Bernstorff, M. Zehetbauer
Vol. 9., No.10., Pages 894-900, 2015
DOI: 10.3144/expresspolymlett.2015.81
DOI: 10.3144/expresspolymlett.2015.81
Corresponding author: G. Polt 
GRAPHICAL ABSTRACT
ABSTRACT
In-situ X-ray diffraction was applied to isotactic polypropylene with a high volume fraction of α-phase (α-iPP) while it has been compressed at temperatures below and above its glass transition temperature Tg. The diffraction patterns were evaluated by the Multi-reflection X-ray Profile Analysis (MXPA) method, revealing microstructural parameters such as the density of dislocations and the size of coherently scattering domains (CSD-size). A significant difference in the development of the dislocation density was found compared to compression at temperatures above Tg, pointing at a different plastic deformation mechanism at these temperatures. Based on the individual evolutions of the dislocation density and CSD-size observed as a function of compressive strain, suggestions for the deformation mechanisms occurring below and above Tg are made.
