Raman microscopic studies of the distribution of the fungicide fluorfolpetin plasticised PVC films

We have used Raman microscopy (in confocal mode to carry out depth profilin g) to study the distribution and redistribution (by leaching) of the fungic ide, Fluorfolpet, FF (5%) in PVC polymer films placticised using various le vels of dioctylphthalate [DOP]. Molecular distribution maps both in X-, Y- and Z-directions have been used to demonstrate that, although DOP is not lo st on leaching, there was a quantifiable loss of the FF, selectively from t he film surface. The loss varied between a few and 25% and reached a maximu m at similar to 25% DOP content of the film. This maximum at 20-25% DOP als o occurred for the difference in bulk and surface concentrations of DOP. Th is is considered to be related to a combination of molecular mobilities in the film, driven by the plasticisation (T-g) effects of DOP, and the mutual solubilities of the additives in water and PVC. (C) 2000 Elsevier Science Ltd. All rights reserved.