TUBE RENEWAL EFFECTS IN BINARY POLYMER MIXTURES

The effects of tube renewal on the diffusion of deuterated polystyrene (d-PS) into binary mixtures of polystyrene (PS) and poly(vinyl methyl ether) (PVME) were examined by using elastic recoil detection (ERD). The molecular weight and volume fraction, phi, of PVME were kept constant in each mixture while the molecular weight of PS was allowed to vary. The contribution of tube renewal to the diffusivity of the d-PS chains was smaller in these mixtures than observed for the diffusion of d-PS into PS hosts. A model based on the work of Klein and Graessley was developed to describe these observations. The relaxation times of the PVME chains in the mixtures were extracted from the data. This information, together with the relaxation times of the d-PS chains, was used to calculate the temperature dependence of the viscosity. The calculated values are in surprisingly good agreement with independent viscosity measurements.