A NUCLEAR-MAGNETIC-RESONANCE STUDY OF MOLECULAR ANISOTROPY IN STRAINED NETWORKS AND NETWORK BLENDS

The splitting of the nuclear magnetic resonance line, seen in strained networks, is shown to originate from the anisotropic screening of the excluded volume interaction by density fluctuations. In a blend conce ntration fluctuations also contribute to the screening and are greatly enhanced if the phase separation point is approached. The effect on t he line shape has been calculated and is shown to be sensitive to the thermodynamics of the phase separation.