6本の枝をもつ星形ポリスチレンとその濃厚溶液の粘弾性的性質

抄録

The viscoelastic properties of star-shaped polystyrenes having six branches and their solutions were measured and compared with those of four-branch and linear polystyrenes. The dependence of the rheological parameters, such as zero-shear viscosity η₀ and steady-state compliance J_e⁰, on the molecular weight and concentration were discussed. At a constant molecular weight, η₀ decreases with increasing number of branches in the polymer molecule. Molecular weight dependence of η₀ for branched polystyrenes having a constant molecular weight of branch, is very similar to that for comb-shaped and randomly branched polystyrenes. J_e⁰ clearly depends on the molecular weight even in the entanglement region, and the critical concentration evaluated from J_e⁰ is two times higher than that from η₀ for branched polystyrenes.