|Title||LOCAL POLYMER AND SOLVENT DYNAMICS IN AROCLOR SOLUTIONS - IMPLICATIONS FOR SOLVENT MODIFICATION|
|Publication Type||Journal Article|
|Year of Publication||1992|
|Authors||Gisser, D. J., and M. D. Ediger|
|Type of Article||Article|
|Keywords||DEPENDENCE, DILUTE-SOLUTION, FRICTION, MAGNETIC-RELAXATION, MOLECULAR-MOTION, NMR RELAXATION, POLYBUTADIENE, POLYISOPRENE, POLYSTYRENE, VISCOSITY|
The high-frequency limiting viscosity of polybutadiene/Aroclor 1248 solutions is known to be less than that of neat Aroclor. This effect has been attributed to polymer-induced modifications of solvent relaxation. We have performed C-13 NMR relaxation experiments to examine simultaneously the rotational dynamics of both components of these solutions. Local segmental motions of polybutadiene are more rapid than solvent rotation. This is unlike the behavior in low-viscosity solvents. With decreasing temperature, solvent rotation slows much more dramatically than do polybutadiene dynamics. Polyisoprene/Aroclor solutions show similar behavior. Polystyrene local dynamics in Aroclor are slower than Aroclor reorientations and have a stronger temperature dependence. The relative time scales for polymer and solvent motion are shown to be an important factor in interpreting solvent modification studies from other laboratories.