Complex viscosity of star-branched macromolecules from analytical general rigid bead-rod theory

Abstract

The complex viscosity of planar star-branched polymers has been derived from general rigid bead-rod theory, but only for singly-beaded arms. Here, we explore the respective roles of branch functionality, arm length, and nonplanar arrangements, analytically from general rigid bead-rod theory. For nonplanar, we include polyhedral, both regular and irregular. Further, for all structures, we compare with and without the central bead. We fit the theory to complex viscosity measurements on polybutadiene solutions, one quadrafunctional star-branched, the other unbranched, of the same molecular weight (Mw= 200 000 g=gmol). We learn that when general rigid bead-rod theory is applied toquadrafunctional polybutadiene, a slightly irregular center-beaded tetrahedron of interior angle 134 is required (with 1 360 000 g/gmol per bead) to describe its complex viscosity behavior. © 2021 Author(s).