(345f) Simulation of Chain-Length Differentiated Properties in High-Pressure High-Temperature Ter-Polymerization

For the design of polymer materials, the properties of the macromolecular ensemble, more precisely their application properties, are the demanding driving force. These properties are determined by the microscopic polymer structure, which is controlled by process conditions in combination with the reaction kinetics. This is a complex interaction. For this reason, with a limited number of monomers an extremely broad variety of polymeric materials can be designed. This points out the large potential of creativity both, a polymer chemist and a process engineers, can use to design new products.

It is essential to have a detailed knowledge about the kinetics of the elementary polymerization steps. These are summarized and conserved in a kinetic model. Such well designed kinetic models help to reach the ultimate goal of a computer-assisted product design. For this it is essential that the predictive potential of such models is significant.

The current state of the art will be demonstrated on the base of technical co- and ter-polymerizations. The materials of interest are cold flow improvers for fuels. The figure shows exemplarily for a ter-polymer the state of the art in terms of quality of description that can be achieved for the molecular weight distribution as well as for the chain-length differentiated incorporation of co-monomer. The red line and data points indicate experimental results while the other represent individual simulation results. For modelling the simulation tool PREDICI that utilizes the hp-Galerkin method on combination with the concept of boundary density functions.

On the experimental side the interest will be directed to the calibration of the size-exclusion chromatography and reproducibility of molecular weight determination inspecting results of independent labs. The comparison of different setups as well as coupling with infrared- and mass-spectroscopy will be discussed.

Furthermore, it will be demonstrated how the simulation well help to get deeper insight into the microscopic structure of the co-polymers. Especially, quantities are of interest for which there exist no methods of experimental determination such as sequence-length distributions.

The authors acknowledge the intense collaboration with the Deutsche Kunststoff Institut Darmstadt, especially Dr. H. Pasch and Dr. R. Brüll, and with Prof. Chr. Barner-Kowollik, KIT in academia and with I. Garcia Castro, BASF SE, in industry.