Interaction between UV radiation and filled polytetrafluoroethylene (PTFE). II. A multiple scattering analysis

The second part of the series, this article analyzes the way UV light propagates through pure and filled PTFE. We investigated the diffusiveness of the semicrystalline matrix as well as the effect of scattering and absorbing fillers (CaF₂ and TiO₂) on the attenuation. The UV-visible absorption curves have been determined by spectrophotometry. A theoretical calculation based on a four-flux multiple scattering approach allowed us to satisfactorily reproduce the experimental results, highlighting the respective importance of the coherent and the diffuse fields. In light of this model, we discuss the influence of multiple scattering on the extent of degradation when PTFE is exposed to a high energy UV radiation. This approach provides of a comprehensive view of the damaging effect of UV light on PTFE, showing a good agreement with the experimental results of the previous article. © 1998 John Wiley & Sons, Inc. J Polym Sci B: Polym Phys 36: 2069–2083, 1998