@article{oai:nagoya.repo.nii.ac.jp:00030619, author = {Noda, Ichiro and Takahashi, Yoshiaki}, issue = {2}, journal = {Memoirs of the School of Engineering, Nagoya University}, month = {Mar}, note = {Viscoelastic properties and structures of polymer blends were studied in the homogeneous and inhomogeneous regions, and in the vicinity of phase separation. In the homogeneous region, the zero-shear viscosity, the steady state compliance and the plateau modulus are very similar to those of polymer solutions, when the composition of high molecular weight component and the molecular weight of major component are low. In the inhomogeneous region, the stresses and domain sizes in steady states and the stresses in transient states in the step-up and step-down measurements agree with the scaling relations in the theory of Doi and Ohta, while the dynamic moduli in the dynamic measurements with pre-shear agree with the theory of Palierne, but not with the theory of Doi and Ohta, when the viscosity ratios of droplet to matrix is small. However, the dynamic moduli were consistent with stresses at the initial stage in the step-down measurements. The difference in the viscoelastic behaviors is caused by the difference in the change of domain structures by shear flow. When the viscosity ratio is large, however, the agreement between the experimental and theoretical results is worse because the domain structures are not well regulated by shear flow. In the vicinity of phase separation, the shear viscosity and compliance at the shallow quench conditions are enhanced at low shear rates, but they become almost the same as those in the homogeneous region at shear rates higher than the critical shear rates, implying the shear-induced homogenization. At the deep quench conditions the steady stress is consistent with the theory of Doi and Ohta, implying no shear-induced homogenization.}, pages = {109--154}, title = {Viscoelastic properties and structures of polymer blends}, volume = {49}, year = {1998} }