July 2- 7, 2017
Xenocs will be attending EPF2017 in Lyon, France.
- Come &Â meet us on booth # 9 !
- EPF Scientific Lunchtime Session organized by Xenocs :
Tuesday July 4,Â 1-2 pm,Â Gratte-Ciel 1&2
Download the flyer of this session
â€œ Nanoscale x-ray characterizationÂ of polymers in the laboratoryâ€
Synopsis : This scientific session will review the progress in characterization of polymeric or macromolecular systems such as films, solutions, surfactants or finely divided organic polymer materials, using small and wide angle x-ray scattering.
Chairman : Pierre Panine, Xenocs
Confirmed invited speakers :
Anthony J. Ryan
OBE, Professor of Physical Chemistry, Department of chemistry, University of Sheffield, UK
â€œWhat can't you do on a Xeuss?â€
Abstract :Â Having a SAXS/WAXS beam-line in the basement of you laboratory means you can do lots of things you had previously needed a synchrotron for. We will give examples of structures formed by reaction induced self-assembly of polymers and colloids, flow induced crystallisation, and by watching paint dry.
- Â Bart Goderis
Associate professor Faculty of Science, Head of Polymer Chemistry and Materials, KU Leuven, Heverlee,Â Belgium
â€œOn the temperature dependent morphology of Polyamide 11: The topology of crystalline, mesomorphic, rigid amorphousÂ and mobile amorphous fractions.â€
- Goderis1, D. Baeten1, O. Verkinderen1, P. Adriaensens2, V.B.F. Mathot1, P. Van Puyvelde3
1Polymer Chemistry and Materials, KU Leuven, Heverlee, Belgium
2Applied and Analytical Chemistry, UHasselt, Diepenbeek, Belgium
3Soft Matter, Rheology and Technology, KU Leuven, Heverlee, Belgium
A two-phase model consisting of alternating amorphous and crystalline layers is often used to describe the morphology of semi-crystalline polymers. However, this simple model â€“ at least in the case of polyamide 11 - does not allow rationalizing the outcome of different techniques which are sensitive to particular features of the semicrystalline morphology.
Several authorsargued for the existence of a rigid amorphous fraction (RAF), which is material with a higher density and lower mobility than the liquid like amorphous fraction but without the order of the crystalline. Although the existence of this RAF seems beyond dispute, there clearly is no consensus on its topology. Based on a combination of temperature dependent WAXD, SAXS, solid state NMR and density measurements a new morphological model is proposed for PA11, which consists of alternating solid and mobile (liquid) amorphous layers. The solid layers are in turn composed of crystalline and rigid amorphous patches with the density of the latter being intermediate between that of mobile amorphous and crystalline matter.
In a next stage, this morphological model, based on using laboratory X-ray equipment, was used to interpret time resolved synchrotron SAXS and WAXD data, collected during the isothermal crystallization of PA11 at different degrees of supercooling. The sample holder was a fast scanning chip calorimeter, which allowed for an accurate temperature control, also at very high degrees of supercooling. WAXD data revealed that mesomorphic material was produced in less than a second at high supercooling, whereas at very low supercooling crystals were obtained. The crystalline to mesomorphic ratio was found to increase gradually with increasing crystallization temperature. Analysis of the SAXS data supported the existence of a crystallization temperature dependent semicrystalline morphology composed of alternating solid and liquid-like layers with the solid layers made from crystalline, mesomorphic and rigid amorphous patches. Moreover, the crystalline or mesomorphic patches alternate with rigid amorphous patches in neighboring solid layers. The relation between details of this peculiar morphology and the crystallization rate as a function of the crystallization temperature will be discussed.
- Â Peter HÃ¸ghÃ¸j
Xenocs CEO, Grenoble, France