Rheological characteristics of hyperbranched polyesters

When the effects of physical aging below T-g are erased, the rheological response of a series of aliphatic hyperbranched polyesters is Newtonian and the melt viscosity scales roughly linearly with M-w at high M-w, indicating entanglement to be absent. The rheological behavior is also highly sensitive to the nature of the terminal groups, suggesting the overall behavior to be close to that of an assembly of compact core-shell "particles". There are therefore strong parallels between the physical behavior of the hyperbranched polyesters in question and that of their ideal dendrimer analogues.