Chapman sees ripple effect of his fluid theory at recent conference

Chapman sees ripple effect of his fluid theory at recent conference

BY JADE BOYD
Rice News staff

Chemical Engineering Professor Walter Chapman had the rare honor of attending a conference in December that was dedicated entirely to an area of study he helped establish over the past 15 years.

Chapman first described Statistical Associating Fluid Theory (SAFT) in 1988, and the approach has since been adopted by dozens of academic and industrial research groups worldwide.

SAFT is a set of equations that allows chemists, chemical engineers, physicists and others to make very precise predictions about the behavior of liquid solutions of solvents and polymers. Polymers are large molecules made up of long chains of smaller molecules called monomers. Monomers — like ethylene, for example — typically contain just a few carbon and hydrogen atoms. Polymers, on the other hand, can contain thousands of monomers, each connected to the other by chemical bonds between the individual monomers.

SAFT lets researchers calculate macroscopic properties — like the temperature and pressure at which a tank full of liquid will change from one liquid phase to another — based solely on the molecular forces between the monomers in the chain.

Polymers are of central importance to the chemical industry because they are a primary product used in plastics, foams, synthetic fibers and films. Prior to the development of SAFT, finding the optimal conditions for processing specific types of polymers involved a great deal of expensive experimentation. Like a chef trying out a new recipe, chemical engineers would vary ingredients, temperatures and pressures to see what method worked best.

With SAFT, companies have been able to optimize many processes, Chapman said. This can lead to significant savings in energy and raw materials since optimized processes waste less heat and produce fewer by-products.

The SAFT03 Symposium, held in Barcelona Dec. 12, explored the latest work underway around the world to further develop SAFT. About 40 scientists attended. Among the most gratifying new work is that of physicists and engineers who are using SAFT to conduct basic rather than applied research.

”I came away with a greater appreciation of how far you can stretch the theory, and I hope others did too,” Chapman said. ”Applications of SAFT now range from polymer processing to predicting molecular structure and properties of fluids in nanomaterials.”