Kinetic Modeling and Optimization of Polymerization Reactions

Specialty polymers often involve polycondensation mechanisms. Our goal is to identify the kinetics and to develop optimization strategies for achieving desired polymer properties while minimizing by-product formation. The tasks typically involved in the analysis of acid-alcohol based polycondensation reactions are:

• What are the kinetics of the polycondensation reactions?
• What is the optimal alcohol to acid ratios to ensure desired molecular weights?
• What is the optimum pressure profile and pressure transition points to ensure desired polymer properties?

In this work, we illustrate our approach to answer these questions. Polycondensation systems are usually characterized by reversible reactions that require the removal of water or alcohol, usually by pressure reduction, to drive the growth in molecular weights and polymer properties. Furthermore, by-product formation reactions need to be minimized to the extent possible. Accurate kinetic model development is a crucial first step in order to optimize these systems.

For a single phase acid-alcohol polymerization, equi-molar ratios are ideal to achieve high molecular weights. However, for multiphase systems, this is not the case, since the alcohol is distributed between the phases, and therefore, some excess of alcohol is needed. The optimum alcohol excess depends on reactor conditions such as the temperature and pressure profiles, which presents an interesting dynamic optimization problem.

We will present our approach to develop the kinetic model and strategies for reactor optimization. In solving the problem for a variety of projects, we have developed a systematic tool that delivers substantial productivity in the processes of estimation, simulation and reaction optimization. Project execution is improved by having a common framework for experimental data storage, kinetic estimation and reactor optimization. Results for the polycondensation kinetic estimation and optimization will be shown along with explanation of the generalized infrastructure we have built to analyze reaction systems.