Investigating miscible polymer blend dynamics with optical and mechanical rheometry

A method to identify component contributions to the rheology of miscible polymer blends is proposed based on complementary infrared polarimetry and mechanical rheometry. With such measurements the blend dynamic modulus, G^*(ω), is shown to be separable into the individual contributions experienced by each of the blend components. The method relies on converting the observables of dynamic infrared 1,3 dichroism and birefringence experiments to those of dynamic shear stress experiments through the use of constitutive relations and the application of the stress-optic rule. Measures are introduced to account for local orientational correlations since such coupling effects are known to influence optical anisotropies but not the state of stress.