Title:

Abstract:

The thermodynamic properties of polymers depend on the chemical nature of the monomers, the molecular weight distribution function, the degree of branching and the degree of crystallinity. For designing novel resource efficient synthesis, manufacturing and recycling processes the knowledge of the impact of polymer characteristics on thermodynamic properties under respective processing conditions is of crucial relevance. Recently, a theoretical framework was developed [1,2], which takes these issues into account. This theoretical approach is based on the Lattice Cluster Theory (LCT) originally developed by Freed and Coworkers [3]. Within the LCT the Helmholtz energy can be obtained by double series expansion in inverse coordination number and in interaction energy taking into account the molecular architecture. The degree of crystallinity can be incorporated using an approach suggested by Flory [4].

With this contribution, we demonstrate the developed framework for predicting and tailoring polymer fractionation processes and for predicting gas solubility in semicrystalline polymers.  In polymer fractionation, we focus our attention on the crystallization based fractionation. For fractionating polymers based on crystallizing polymer out of solution, major influence factors are molecular architecture, the degree of crystallinity and the solvent interaction of the polymer. We show, how the developed theory can be applied to different polymer solvent systems to predict polymer crystallization, dependent on these respective influence factors.

As a second example, we present the prediction of gas solubility in polymers. In the case, where crystalline and amorphous areas are present within the polymer, crystallites must be taken into account as additional internal physical constraints covering the effect of an internal pressure induced sorption behaviour change of the amorphous phase [5]. The combination of mechanics and thermodynamics allows the prediction of the arising internal phase pressure and it’s influence on the gas solubility  [6]. Results for gas solubility predictions for different polymer-solute systems will be presented for different pressure and temperature ranges. Results are compared with experimental data from the literature [8].

Biography:

Michael Fischlschweiger is full professor at Clausthal University of Technology. He is heading the Chair of Technical Thermodynamics and Energy Efficient Material Treatment at the Institute for Energy Process Engineering and Fuel Technology. He holds a BSc and MSc in Polymer Engineering & Science and a PhD in Materials Mechanics and Numerical Mathematics from the University of Leoben, Austria. The doctoral theses was conducted jointly between the Centre des Matériaux (MINES ParisTech) and the University of Leoben. Additionally, he holds a PhD in Thermodynamics from Technical University of Berlin. His major research focus is on theoretical and experimental thermodynamics for developing resource efficient materials, processes and products.