Chemical analysis of polymer blends via synchrotron X-ray tomography

Material properties of industrial polymer blends are of great importance. X-ray tomography has been used to obtain spatial chemical information about various polymer blends. The spatial images are acquired with synchrotron X-ray tomography because of its rapidity, good spatial resolution, large field-of-view, and elemental sensitivity. The spatial absorption data acquired from X-ray tomography experiments is converted to spatial chemical information via a linear least squares fit of multi-spectral X-ray absorption data. A fiberglass-reinforced polymer blend with a new-generation flame retardant is studied with multi-energy synchrotron X-ray tomography to assess the blend homogeneity. Relative to other composite materials, this sample is difficult to image due to low x-ray contrast between the fiberglass reinforcement and the polymer blend. To investigate chemical composition surrounding the glass fibers, new procedures were developed to find and mark the fiberglass, then assess the flame retardant distribution near the fiber. Another polymer blending experiment using three-dimensional chemical analysis techniques to look at a polymer additive problem called blooming was done. To investigate the chemical process of blooming, new procedures are developed to assess the flame retardant distribution as a function of annealing time in the sample. With the spatial chemical distribution we fit the concentrations to a diffusion equation to each time step in the annealing process. Finally the diffusion properties of a polymer blend composed of hexabromobenzene and o-terphenyl was studied. The diffusion properties were compared with computer simulations of the blend

Burning issues in tomography analysis

Researchers are using 3D multispectral imaging methods such as synchrotron X-ray tomography to assess the effectiveness of blending polystyrene with flame retardants to make them safer. The ability to image materials with a wide range of X-ray energies yields 3D elemental maps. These maps measure chemical homogeneity and with time-dependent imaging, diffusion and transport properties. The beamlines are mostly automated and can be enhanced with sample changers. Experienced users and staff scientist will manually adjust optics, slits, monochromators, interferometers, scintillators, and detectors for maximum performance. Users need secure, remote access to imaging equipment, and beamlines need protection from unauthorized users