Many industrial polymer applications involve composites of a polymer with some hard filler. Systems with filler offer numerous advantages over virgin polymer. Typically the filler is a low cost material that reduces the overall cost of the piece and also adds strength and toughness.

Fillers have long been in use for many years to improve polymer properties, however a fundamental understanding of the system is lacking. The interactions of polymer chains with the filler particles is not well understood. We aim to explore these interactions by studying the diffusion of a tracer chain of dPS, deuterated polystyrene, though a matrix of PS and silica filler. As would be expected we found that the diffusion coefficient slowed as the amount of filler in the system was increased. We plan to develop a model to explain this polymer motion. Below is a plot of the diffusion coef. for tracer film of 336k dPS moving through PS with various amounts of silicon particle filler:

Forward Angle Recoil Spectrometry, Fres, is employed to elicite the depth concentration profile of the diffusing species, dPS. A typical Fres spectum is shown below. Here a 200 A layer of 336k dPS diffuses into a thick layer, 30 microns of the filled polystyrene. Preliminary results have shown that indead the diffusion is reduced by the addition of increasing amounts of filler.