Viscoelastic study of oil diffusion in molten PP and EPDM copolymer

In the second part, the transport of the plasticizer in the polymer matrices is followed during viscoelastic testing. The molecular weight of PP in shown to have no influence on the diffusion kinetics, whereas diffusion appears faster in EPDM. The implementation of a model relying on a Fickian description of diffusion leads to satisfactory agreement with experiments for PP only, and allows for the calculation of the oil/polymer mutual diffusion coefficient. Again, a poor quality of fit is achieved with EPDM, suggesting that elastic diffusion is enhanced with this polymer.