Segmental and terminal dynamics in miscible polymer mixtures: Tests of the Lodge-McLeish model

The Lodge-McLeish model of miscible blend dynamics is compared to literature data for the segmental or terminal dynamics of components in six different miscible polymer mixtures. In most cases, the model successfully fits the experimental data for a given component with a parameter phi(self), which is independent of temperature and composition. In most cases, the fitted value of phi(self) is close to the model prediction, providing some support for the assumption that the Kuhn length is the relevant length scale for dynamics in miscible polymer mixtures. In other cases, the model either fits the data with phi(self) values much different than those expected based on the Kuhn length, or fails to fit the experimental data for any value of phi(self). Using the Fox equation as input to the Lodge-McLeish model provides a better description of the experimental data than using the measured mixture T-g values. (C) 2003 American Institute of Physics.