MEASURING THE DIFFUSIVITY OF ADDITIVES IN POLYMER FILMS USING IN SITU FTIR-ATR SPECTROSCOPY

摘要

In many polymer-film applications, additives migrate from the bulk of a film to the film surfaces. For these cases, it is more realistic to measure the additive diffusivity in a diffusion-out mode rather than using a mass-sorption (diffusion-in) experiment. This is particularly true for additives that are solids at the testing temperature. This research focuses on the evaluation of additive diffusivity in a diffusion-out mode via in situ FTIR-ATR spectroscopy, which has the advantage of requiring only small samples of thin films. The technique will be described, including methods to obtain reproducible contacting pressure between a film sample and an ATR crystal and to perform in situ experiments at elevated temperatures. Diffusivity results are presented for the migration of an erucamide slip agent in LLDPE films.