Three-Dimensional Chemical Analysis and Molecular Dynamics Simulations: Application to Flame Retardants in Polymers

Louisiana State University, Baton Rouge LA

Investigators

Abstract

Professors Leslie G. Butler and Randall W. Hall of the Louisiana State University and Agricultural and Mechanical College are supported by the Analytical and Surface Chemistry Program in the Division of Chemistry for conducting three- dimensional chemical analysis and molecular simulations with applications to flame retardants in polymers. The application of three-dimensional imaging methods to chemistry is new, thus, methods for image analysis will be developed. Images will be acquired with synchrotron X-ray tomography in a mode that yields elemental concentrations throughout a 2 millimeters cube at a resolution of 3 micrometers. As sample ages, it is expected that good flame retardants dissolve into the polymer and bad flame retardants form internal domains and surface blooms. The diffusion rates, activation energies, and diffusion mechanisms will be measured experimentally and compared with theoretical simulations. Three-dimensional imaging offers new views of chemistry in solids, like the diffusion of molecules through glassy polymers. Computer simulations of glasses can describe the structure and dynamics of glasses and thus diffusion of molecules through a glass. A practical example is the slow (years) diffusion of flame retardants through polymers. Sometimes, the dusty feel on old CRTs and printer cases is caused by the precipitation of flame retardants and is informally called "blooming". A common example of blooming is the diffusion and surface precipitation of cocoa butter on the surface of old chocolate. A web-based tutorial will be created to introduce the students to basic sciences and the three dimensional image analysis aspects of this research.