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 diffusive ness of the semicrystalline matrix as well as the effect of scattering and absorbing fillers (CaF2 and TiO2) on the attenuation. The UV-visi ble absorption curves have been determined by spectrophotometry. A the oretical calculation based on a four-flux multiple scattering approach allowed us to satisfactorily reproduce the experimental results, high lighting the respective importance of the coherent and the diffuse fie lds. In light of this model, we discuss the influence of multiple scat tering on the extent of degradation when PTFE is exposed to a high ene rgy UV radiation. This approach provides of a comprehensive view of th e damaging effect of UV light on PTFE, showing a good agreement with t he experimental results of the previous article. (C) 1998 John Wiley & Sons, Inc. J Polym Sci B: Polym Phys 36:2069-2083, 1998.